Porsche 928 Drivetrain FAQ
Replacing Transaxle Fluid
In a message dated: 4/19/99
>Mark E. Rosenfield wrote:
>I get my hands on my 89 S-4 for the first time.
Congrats!
>…I am looking for information on changing the transaxle fluid.
You need a 17mm hex drain plug socket and a suction gun. Plews Tools makes both for ~$7 and ~$10 respectively.
1) Raise the back end of the car to provide working room.
2) Remove the FILL plug first. If you remove the drain plugs but can’t open the fill plug, you’re hosed.
3) Place catch pans under the front and rear drain holes and remove the plugs.
4) After draining the old fluid, replace the front and rear drain plugs and torque to 14-17lb/ft.
5) Fill the suction gun with 75W90 gear oil and fill the transaxle with 4qts of oil.
Red Line is a very good synthetic that offers a different oil depending on whether the car has a limited slip. For no limited slip, use 75W90NS; for limited slip units, use 75W90. Swepco is a good brand of dino-oil lube.
The whole job takes about 25 minutes.
—
Jim Stadter
’83 928 S 5-speed (U.S. spec)
’88 928 S4 5-speed
Hill Country Region PCA (Austin)
In a response dated: 4/19/99
If you don’t have a sucking device as I did not! I opened the battery cover, inserted a funnel into a piece of 1/2 inch hose about 10 inches long, snuck it between the battery box and the body right into the upper hole of the differential cover and filled it that way. Leave the pan under the differential so it can tell you when it is full! Don’t forget the car needs to be level else you will over fill it.
Mark Grasser
1978 928 5-speed
Guards red/black/tan sheepskins
928 OC Charter Member
In a response dated: 4/19/99
>Mark Grasser wrote:
> If you don’t have a sucking device as I did not! I opened the battery
> cover, inserted a funnel into a piece of 1/2 inch hose about 10 inches
> long, snuck it between the battery box and the body right into the upper
> hole of the differential cover and filled it that way.
I don’t have any openings between the body and the battery box that would facilitate doing this. Perhaps your trick only applies to earlier cars with the bolt-on battery boxes?
> Don’t forget the car needs to be level else you will over fill it.
Good point.
—
Jim Stadter
’83 928 S 5-speed (U.S. spec)
’88 928 S4 5-speed
Hill Country Region PCA (Austin)
In a response dated: 4/19/99
Jim,
You can still fill without the vacuum pump and it’s less work. Buy about three feet of 3/8″ hose and a funnel that friction fits into it. 3/8″ hose friction fits between the battery box and the gas tank. One end in the fill hole in the transaxle the other end behind the car higher than the fill hole. I lean a 1 x 6 up against the back of the car and nail the funnel to it just above the hatch opening. Pour the bottles of oil in slowly and put a pan under the fill hole so you know when you have it totally filled. Don’t forget the front plug when draining. Make sure the car is level. A torpedo level on the door sill works pretty good.
Good luck!
Jay F. Kempf
Gear Oil Capacity
In a question dated: 4/17/00
Hi all,
Just a quick question please:
I own a 1983 European S 5-speed, and have just finished changing its gear oil. Since it is stated in the sales brochure that the gear oil capacity is 3.8 liters (1 gallon), that was the amount I have bought – 4 liters. The problem is when I pumped all the 4 liters in it (through the upper plug on the rear diff cover), it still didn’t overflow. Have I missed something? Is there supposed to be more than 4 liters of oil in my transaxle?…
Looking forward to reply as I have to drive the car home, and wouldn’t like to destroy my box…
Thanks in advance
Boris
In a response dated 4/17/00
take an allen wrench and stick the bent end in the hole to measure the level. My pinkie finger is usually small enough to do the same thing and I can’t loose it. (I’m sure I left myself open for something, what I don’t know) If it is within a half inch or so I am sure you’ll be fine. just buy some more and add it later.
Mark [Grasser]
Rebuild or Replace
In a message dated: 5/27/00
Raise your hand if your synchros protest each shift…OK, that’s about 90% of ya’:). Herewith a “nudge” that’ll get you enjoying the lower gears again.
Mid-season last year saw my 4th gear refuse to participate (wouldn’t engage). This, plus the obligatory graunches associated with the ZF synchros in 1st, 2nd and 3rd, made the winter project decision easy…the box needs a rebuild.
Talked to the local shops who supposedly know what the insides of a 928 transaxle look like and found their estimates much too vague. Since the gang at 928 International had been so helpful when creating my “Stuttgart hybrid”, who better to ask about a rebuild.
To my delight, they offer an exchange program. Not only would I not have to wait for my box to come back, they could install an LSD in the “new” box.
Done deal…especially thanks to my dear wife’s suggestion that a transaxle seemed the appropriate gift for our 25th anniversary! Gotta love that girl!!
So, if you’re on the fence about what to do for your transaxle, this is a not very subtle endorsement of the plan offered by 928 International. You get a rebuilt unit with the work done by people who know what they’re doing. While you’re at it, get rid of the 2.20 ratio and order the 2.75 w/ LSD. They’ll be happy to oblige:).
See some of you at Watkins Glen on the 15th and hopefully a bunch more at Hallet and/or Wichita in July!
Best regards,
David Lloyd
Farmington, CT
’79 Euro, “Stuttgart-hybrid” track car
928 OC Trackmaster
Transaxle Leak
In a message dated: 8/29/00
Over a year ago I removed my transaxle and took it to the local independent Porsche shop for syncro replacement. It was expensive, but they did a great job of the internal work. In combination with a complete clutch job, the car shifts great. However, ever since the work was done it has always leaked badly from the top cover. I removed the box and found that the top cover gasket was not sealed. Assuming this was the problem, I glued down the gasket and re-installed the box. It still leaked. I carefully measured the amount of oil in it and it still leaked.
Now, a year later I am getting really fed up the the leak and removed the box one more time. I took it back to the shop and they finally opened it up 4 weeks after I took it there (I was on holidays for 2 of the weeks). Today the owner calls me and tells me he has no idea why it is leaking from the vent and asks me to follow up on my own with my net resources. This shop calls themselves Calgary’s Porsche experts!
After getting the call, I sent an urgent note to Mark Anderson at 928Intl inquiring as to what the problem could be. In less than 10 minutes Mark sends me a reply with the solution; an incorrect gasket was installed which leaves the cover vent open to the oil splash. The correct gasket goes half way across the top of the box acting as a baffle which prevents the oil splash from hitting the vent. New gasket is on order and I am hoping to get the box back in a few days. I will let the list know what happens, but I am sure the problem will be solved.
Mark. Thanks again to you and 928 International for the great service you provide to all 928 owners. I only wish you were closer to Calgary.
Dean Cockshutt
’83 Euro 928S
SECTION 2: Shifting
In a question dated: 5/21/99
I jumped off Poschefans last year when I put my ’81 928 to bed for the winter. It took me a while to find all of you again. It is good to see that a list is still going strong for the 928.
My 928 came out of hibernation well initially. I had a “slow” power window regulator on the right side. I had to do some trim and speaker repair to that door and when I had removed the panel I could see that the nylon idler wheel for the power window had split. PO must have known about this because the stops had been reset to allow the window to travel up further. A dangerous situation when you consider that the window could have popped out of the track and fallen. After my local dealer swore up and down that no replacement wheel was available and that I was looking at an entire regulator assembly, Dave Roberts provided me with a new wheel and pin for a couple of bucks. I was not surprised that these arrived in Porsche part bags, the local dealer is an idiot. In the mean time I had a brass wheel machined (when I thought nothing was available) but decided not to use it as I was concerned about rattle. The window did rattle before the repair but is fine now. Just a hint for anybody attempting this repair; don’t forget to clamp the window glass in the closed position. This is easily accomplished by opening up a hose clamp and then fastening it around the tubed track so the window cannot fall.
I have another, more serious, problem. I had the Shark out yesterday and I could feel my shifter going “soft”. At one point when I shifted up to 2nd my hand almost struck the radio. Following that, I had no gears and ended up, embarrassingly, pushing the car through a busy, and angry, intersection.
It is not a mystery. I had the car towed and quickly spotted the problem. There is a rod that goes forward from the shifter and anchors at the front of the tourque tube (on top of the tube unfortunately). This rod had a ball socket assembly on the end (much like a miniature tie rod end). The socket has become dislocated from the ball. I have removed the heat shields, catalytic converter and cross bridge member. I can see it, touch it and I’m confident that I can get a wrench on the rod to remove the old socket half of the joint which is removeable with a wrench. The problem is I can’t see how the stud part is attached to the torque tube. It doesn’t appear to be machined for a wrench. Even if it were, I don’t know how I would get a tool on it. The only thing I can think of is it may be accessible somehow through the site hole for the shaft coupler that is just below it. Failing this I would have to remove the entire tube assembly? Tell me it ain’t so!
I have put in a call to Dave Roberts but I know how busy he is so he may not be able to get back to me. Can anyone else help? I am not going any further until I know at least a bit more.
Joe PENDLETON
’81 928 Pewter
In a response dated: 5/21/99
Dear Joe:
We are living parallel lives as this happened to me on Monday. The shop I took the car to was able to replace the socket connector in about an hour.
You do not have to remove the ball, just the socket. The socket is screwed into the shifter linkage shaft and held in place by a lock nut. Count the number of exposed threads, loosen the nut, then unscrew the connector. Install the new one in reverse order. Make sure to maintain the same number of exposed threads. The hard part will be getting the socket over and onto the ball. The mechanic was able to do it on the first try with the help of a large screw driver that looks more like a pry-bar. Once it’s on, tightening the locknut.
Good luck and merry motoring, Ed.
In a response dated: 5/21/99
Joe,
You don’t need to replace the stud that is fixed on the torque tube. Just replace the ball cup on the end of the shift rod. There’s a nylon insert in the cup which has worn out and allowed the cup to come off the stud.
Ed’s mechanic _somehow_ managed to fix this problem on Ed’s car recently in just under an hour. Aside from the fact that he had a lift, I am still clueless on how he could have done this so quickly since it took me waaayyy longer. On my ’83, there is a bearing welded on top of the torque tube through which the front guide rod runs. This bearing prevents you from moving the guide rod sideways very far to ease access to the ball cup. I’m suspecting that later models may have elminated this bearing and therefore allow more lateral motion of the guide tube.
Ed – since your mechanic does this in less than an hour, I think this would be a great demonstration for the Frenzy. I’d even chip in a few extra dollars to help pay for an hour of his time.
—
Jim Stadter
’83 928 S 5-speed (U.S. spec)
’88 928 S4 5-speed
Hill Country Region PCA (Austin)
In a response dated: 5/21/99
Dear Jim:
You’d be on if the event were to take place at Intersport! I’ll ask Charlie if he would like to show you how it’s done, but he would have to do so with the permission of the folks at ASG. Don’t cout on him being there. Knowing Charlie, he’ll be out flying his model planes.
I suspect that Ray at ASG could also do it in record time if he wanted to. I’ll see if he will take you up on the challenge. BTW, he’s going to show us how he does a “liftless” alignment.
Merry motoring, Ed.
P.S. You are correct, there was no bearing on the GT shifter linkage, which may be why it was relatively easier to install the socket.
Difficulties with Shifter
In a question dated: 9/1/00
My 84s clutch if fairly new about 3000 miles and grabs smoothly and does not slip at all. The problem is sometimes I stop at lights and the shifter is pretty tough to pull out of gear? And the same goes for placing the car into gear, with the clutch pedal all the way to the floor at a dead stop the car sometimes grinds first as if the clutch was not fully engaged. Any tips troubleshooting? -Brandon
Response
In a message dated: 9/1/00
There are two likely possibilities: The clutch hydraulic system needs bleeding. The trick to getting the clutch completely bled is to do the normal bleeding procedure, then remove the bolts holding the slave cylinder to the clutch housing (do not remove the line) and push the clutch rod all the way to the bottom of the cylinder. Reattach and rebleed. The central disc (sic) is dragging. There are three adjustable stops that position the central disc, and these must be adjusted. The procedure is in the Factory Shop Manual, but a verbal description probably wouldn’t make the procedure clear enough for you to follow – it’s hard enough to understand with the pictures.
Wally Plumley
928 Specialists
Upshifts
In a message dated: 8/20/99
There is a relatively easy way to eliminate opinion (informed or otherwise) from both this discussion and the infamous rear end ratio discussion.
The best way to determine the most effective shift points, assuming that you have all of the needed data, is to make a graph. Take the torque curve of the engine, multiply the values of that curve by (first gear transmission gear ratio times rear end ratio) and plot the resultant curve on a graph, showing rear wheel torque on the vertical axis and rear wheel speed on the horizontal axis. Repeat the process using (engine torque) times (second gear ratio) times (rear end ratio), and plot this curve on the same graph. Repeat, substituting third gear, fourth gear and fifth gear ratios, and adding those curves to the graph. Don’t forget that there is a laygear ratio involved! There are pairs of gears on each end of the shaft on all of the intermediate gears, and the ratio on the laygear shaft is different for different years. Just look in the overall gear ratio column in the spec book, not the simple gear ratio column. If you don’t use the correct ratio, all of the intermediate curves will be too low in relation to fifth gear, which has no laygear ratio.
The most effective shift points occur where the curves cross. You just come down the top line on the graph! This visually illustrates that the best acceleration occurs with the max area under the curve.
Now, just for grins, repeat the process with a different rear end ratio, putting the curves on the same graph. Do you still want to spend the big bucks for that 3.08?
Wally Plumley
928 Specialists
Hard Shifting When Cold
In a message dated: 8/26/99
One of our friends from below the equator sent in a question about hard shifting when the transmission is cold. Most of us don’t have that problem at the moment, but will have soon.
My MY86 5-speed has the traditional hard shifting when cold syndrome. A lot of pondering and a little experimentation has suggested an odd possibility that I would like to throw out for consideration.
When it is cold, the first shift is very difficult. I did a little experimenting, and discovered that it doesn’t matter at all whether or not the engine is running. To me, this appears to eliminate the most likely suspect, the syncros. If the syncros were ineffective when cold,
shifting would be hard with the engine running, but easy with it not running.
I now suspect that the problem is caused by a shaft moving into a blind hole filled with gear lube. When the lube is cold, leakage around the shaft is very slow, so the shift is hard. After the lube is pushed out, shifting is easy, even when cold. When the lube is warm, it leaks out by the shaft more easily, so shifting isn’t as hard.
Some of the special gear oil are more of a multi-viscosity type, so they don’t get as thick (viscous) with cold as do the conventional gear oils, so the first cold shift isn’t as much of a problem.
Comments?
Wally Plumley
928 Specialists
2nd Gear Syncro
In a question dated: 11/24/00
My 2nd gear syncro is getting worse- especially in cool weather when I downshift from 3rd to 2nd. My mechanic replaced the the gear oil and added some stuff called Syncro-Shift , no difference. My question is do you think it is worth the trouble to change to Red
Line synthetic- would there be any noticable improvement?
Thanks,
Steve
’83 928s 5 speed
In a response dated: 11/24/00
Steve,
The 2nd gear syncro is toast. I was just through a similar experience, changed fluids, redline, synth, etc, no change. Now that the new syncros are in, life is good. It ain’t that easy, well, the syncros are cheap but
to get the tranny out you need to: remove wheels, brakes, axles, torque tube, shifter coupling, rear cross member – a few hours for me… While you are in there, you should probably do all of the syncros and ensure the gears are ok.
Dean
’88 S4
’79 Euro
SECTION 3: Clutch
Question:
In a message dated: 9/22/00
Hi, I just purchased my first 928 and am without a manual presently. The car is in great shape and only has 50,000 (actual) miles on it. The previous owner put a new clutch (or set) in it last year and then parked it, where it sat till I bought it. The problem is that the clutch doens’t seem to disengage all the way, preventing downshift at any rpm. I don’t have a problem shifting up. I have adjusted the foot pedal to eliminate all but about 3/8 – 1/2 ” of free play. Could this be related to the positioning of the “center” disk? If so, is access to this through the plate that the starter is bolted to? Thanks, Todd Densmore Tdensmore@equityins.com 1979 928
Response(s)
In a message dated: 9/22/00
Very probably. Yes. This adjustment is one of those things that is very difficult to describe verbally. The manual has photos and verbiage, and it still isn’t too clear. Perhaps some day one of us will get the time to do an illustrated article for the Owners Club. Wally
Response(s)
In a message dated: 9/22/00
Todd, The 79 is a bit of a beast compared to other European or Japanese cars, other Porsches and later 928s. Heavy clutch pedal forces and long, high force throws are normal. It is also a bit prone to synchro and hydraulic system wear. I would bleed the system first. I would maybe look at reducing the freeplay in the pedal second. I then look at either changing the tranny fluid to synthetic or adjusting the clutch intermediate plate next. In concert with all that I would work on my shifting with rpm matching. They respond nicely to this. I would guess that you have aging synchros. If that is the case all of the above will make it quite a bit better.
Jay K.
1979 US 5 speed silbermettalishe
21 years young.
PS Welcome to the old buggers club –
Clutch Adjustments II
Question:
In a message dated: 10/23/00
Rennlisters: How does one go about adjusting the clutch from under the dash? What kinds of adjustments are there? Peter Walker 79 4 1/2 spd mit Ansa exhaust
Response(s)
10/23/00
The 928 clutch being of a hydraulic design has no “adjustment” the fluid enters the system as needed to maintain the relationship from clutch master cylinder to slave cylinder. There is some minor adjustment of the pedal position that can be made at the pedal. The clevis is threaded internally and after it is disconnected from the pedal may be turned in or out. This should not be necessary. If you are having difficulty getting the clutch to release completely it is not an adjustment problem but some other issue; bad pilot bearing, bad release bearing, broken ball pivot, miss- adjusted intermediate plate or possible air trapped in the system. —–
Response(s)
10/23/00
There are two adjustments: push rod length; and assist spring. The push rod adjustment isn’t quite as critical as the one on the brake pedal, but should be checked if there is a clutch problem.
1) Loosen the locking nut.
2) Adjust the push rod until it slips freely onto the pin.
3) Lengthen the rod by one turn to preload the cylinder.
4) Tighten locknut, install clip.
The Assist Spring reduces the pedal pressure needed to operate the clutch.
1) Carefully inspect the coil spring located above the clutch pedal – just above your left knee. It may be broken – if so, replace it. You will be pleased at the difference in clutch feel.
2) Measure the distance between the center of the assist spring rod pivot point and the end of the spring under the washer at the adjusting wing nut (uh-oh!). This should be 43 mm up to MY91, and 21 mm for MY92 and up. Adjust by turning the wing nut.
Wally Plumley
928 Specialists
Blue Hose Failure
Question:
In a message dated: 9/9/00
My 79′ has just displayed signs of the “blue hose blow out” of the clutch master fluid line. Can anyone please offer up the best method to attack this one? Thanks in advance, Richard
Response(s)
In a message dated: 9/10/00
Richard, Failure of the dreaded blue hose will produce almost no clutch symptoms other than leakage and loss of fluid at the brake fluid reservoir. If you are having clutch hydraulic symptoms you probably are having problems elsewhere. The dreaded pressure hose under the car is more ominous. That’s the one that did Greg S. in at Hallet and a bunch of others when they least expected it. Everything below the dreaded blue hose is under pressure and can effect clutch operation. You need to check the clutch hydraulic system out and if you are loosing fluid the brake circuit as well. As Dave Lloyd said the brake master/booster is tricky to get out to service the clutch master but there are some tricks to take the pain out. Many have suffered so that you don’t have to. Check the clutch hydraulics and report back and we’ll go from there. Give us some detailed symptoms and we can help you pinpoint it. Good Luck! Jay Kempf
Cutting a Hole for Servicing
Question
In a message dated: 9/11/00
Ok, so now I need to change the blue-hose-of-death (clutch fluid supply) line on my 79′. Somehow I think I would have so much more fun if I got out a high speed rotary cutting tool, climbed under the wheel well and cut a nice big access port. I could easily fabricate an on off coverplate. Could change out the clutch cylinder at a later date w/o removal of the brake components. Whats wrong with the cut and gut approach to this very difficult to access area of the car?? Thanks, Richard
Response(s)
9/11/00
I have seen several 928s with ” magic windows ” cut in the fender well for access to the clutch master cylinder . I assumed that some master mechanic had taken a short cut , literally . The panel in question is structural as it ties together the lower frame rail and the upper triangle support. I do not know how much it is needed, how much it would be compromised by a “service panel ” . It does look like rodent engineering and would make me question how much creative design was done in other places.
Jim Bailey
928 International
jim@928intl.com
79 928 5spd
80 928 5spd
68 911 5spd
Response
9/11/00
Guys, The dreaded clutch master job is not hard it just has pitfalls for the inexperienced. There are even two well know tricks how to get it in and out without messing with the brake booster. For just a blue hose job it should be real possible to get it off and then on the barbed hose fitting. A small mirror and a flashlight would assess the situation. If that doesn’t work you can remove one bolt on the firewall side and then insert a coat hanger hook to hold the master cylinder while removing the other. Then when the other is out you can slightly withdraw the clutch MC to get at the hose connection. It is connected to a hard line that heads down the inner wheel arch wall so it shouldn’t be moved much but then again it shouldn’t take much. Point is there are lot’s of tricks and options. This hould be doable. Cutting holes is not necessary and not a good idea in a shear web near a stressed area like the inner fender or firewall. Jay Kempf
Clutch Release
Question
In a message dated: 9/27/00
Good Morning Everyone, last night while driving home in my new 83′ 928S, I depressed the clutch only to find out that the clutch did not release…. Please tell me that the clutch did not go out, and this requires only a simple adjustment?? I do have a certified 928 mechanic in the area that I am going to bring it to… Any suggestion? Julian
Response(s)
In a message dated: 9/27/00
Sounds like either the clutch master or slave cylinder has bit the dust. Any brake/clutch fluid found under the car? Maybe the supply hose from the brake master cylinder reservoir to the clutch master cylinder is gone. Pretty common problem. Sorry, probably not a simple adjustment! Adam S. ’89 Black 5sp. ’00 Audi S4
Response(s)
In a message dated: 9/27/00
If it’s the same thing that happened to mine last Friday, you have blown out the flex hydraulic hose. Not a nice feeling sitting there with no clutch, I’m not anxious to repeat it. Guy DuHamel 81 5spd
Clutch-Bleeding
3/17/2000
The clutch master cylinder in my S4 started leaking, worked just fine, but leaked fluid onto the footrest. I took it to my dealer and they replaced the clutch MC. When I picked it up later everything was fine (except wallet). The next morning the clutch pedal had excessive free travel, about 30% of the travel was free play. There was just enough travel to release the clutch so I drove it expecting the automatic adjuster to take over. After about 40 or so clutch cycles the free play was gone and everything was as it should be. Next morning the same thing and, after repeated cycles, it was normal. I know I can take it back to the dealer but I’d like to avoid the inconvenience. Looking in the book doesn’t give me a clue as to how the automatic adjuster works. Can anyone give me some insight on what’s happening here? Why is the adjustment changing overnight? Should I readjust the pushrod by the book when the free play is at its max? (the amount of exposed threads on the pushrod looks about right)
John Kunkel
Response(s)
3/17/2000
John,
The automatic adjuster is just the hydraulic circuit. The symptoms you describe are classic “Bad bleed job” symptoms. There is an air bubble caught in the system somewhere. This is affected by temperature and pumping the pedal for short periods. Sometimes they work themselves out and the pedal ends up rock hard and you have to unadjust the lack of freeplay to get normal action. The best way to fix it is to take it back to the garage that did it and have them put the darned thing back up on the lift and do this:
1. Unbolt the slave cylinder still attached to the plumbing.
2. Making sure the fuid does not over flow the rewervoir depress the pushrod on the slave cylinder a few times waiting between cycles for the fluid to equalize.
3. Bolt it back up and finish the bleed job.
The two places where air collects in the clutch hydraulic system are in the top of the master and in the top of the slave cylinders. The slave bubble comes out when bleeding. All other bubbles in the system end up in teh top of the master cylinder. Because it is tilted it is hard to get that one out and that’s why you need the fancy procedure. I have successfully removed the snapring from the front of the clutch master and bled the cylinder through the front by the pedal. Very evffective although slightly messy and you need to stand on your head down by the pedals. NO for the faint of heart.
I think you should go back to the guy that did the job and get him to finish what he started. He should not charge you anything…
Good luck!
Jay K.
Clutch – Vibration
Question
In a message dated: 9/23/99
Hi,
My 86.5 5 speed has a vibration over 3000 rpm and can be felt on the clutch pedal and gear lever. I was told that the clutch fork bush needs replacing and the transmittion needs to be removed to access the bush. My question is do you need to drop the transmittion at access the bush and will this stop the vibration.
Thanks
Chris
Response 9/23/99
Chris,
That’s not even close to the right cause for those symptoms! When you let out the clutch the whole pressure plate assembly turns with the crankshaft so the central shaft assembly and throw out bearing as well as the guide tube are taken out of play. Also, 3000 RPM vibrations are famous in 928’s. That *%^& long drive shaft running at engine revs was a dynamic nightmare for the development engineers. They made it real good by carefully positioning the bearings in the torque tube to eliminate natural frequencies. The tranny and motor mount durometers and positions are also a factor so if they aren’t up to factory specs then the natural frequencies show back up. Annoying but true.
Moral: your symptoms point most likely to bad motor mounts, or bad torque tube bearings.
Definitely don’t need to remove the tranny.
Who told you this stuff?
Jay K.
Clutch Replacement
In a post dated: 4/28/2000
How did you determine that it needs a clutch?
Throwout bearing noise is not really related to the clutch, per se. That is, a throwout bearing may go bad before the friction material is worn off the disks (you have two clutch disks), as may a pilot bearing (the bearing in the end of the crankshaft that supports the end of the clutch shaft.)
In addition, there is a plastic cup between the clutch throwout bearing arm and the ball stud that supports it on the bellhousing that wears out and causes a rattling noise that goes away when you press the plutch pedal.
A 928 clutch is more complex than that found in most cars. It is unlikely that your shop can do the job correctly unless they have the factory shop manuals.
I would suggest a complete clutch job, including replacing the clutch disks and prssure plates, the throwout bearing, the pilot bearing and clutch arm cup, and checking the flywheel surface and the guide tube for scarring.
You are looking at $450 – 600 in parts. The ’78 – ’79 require a different package from the ’80 – ’86 models.
Call David at 770.928.4777 if you want to get the parts from us.
Wally Plumley
928 Specialists
In a response dated: 4/28/2000
THANK you, Wally I know my shop has done clutch replacements before – because my “928 guy” used to race them and they worked on nothing but standards…..
However – I sort of wanted to get the “second opinion” first, so to speak.
So, my thanks, once again…..Dr. PLumly
John H.
SECTION 4: Torque Tube
Torque Tube Replacement Procedure
In a message dated: 3/11/00
Ame,
My symptoms were first a random rattling noise at slow idle and also just
as the engine was switched off. After about a thousand miles or so a typical
bearing noise also developed. Listening under the car, the noise seemed to
come out of the openings in the torque converter housing. Using a
stethoscope, it sounded like it was in the central part of the tube.
The basic steps for torque tube replacement with an automatic
transmission are:
1. Disconnect battery ground strap.
2. Remove rear wheels.
3. Disconnect multi-pin plugs in the front of the spare tire wheel well and
pull the wires through from below.
4. Disconnect oxygen sensor in fuse panel and remove complete exhaust
assembly and heat shields. This would be a good time to replace the oxygen
sensor.
5. Drain ATF and remove reservoir.
6. Disconnect axle shafts at transmission end and suspend in a horizontal
position with wire or chain.
7. Remove the two bolts that mount the transmission to the rear suspension
crossmember. Mark the position of the transaxle with respect to the cross
member so that it can be reassembled in the same position. This will affect
the rear wheel alignment.
8. Suspend the rear of the transaxle from the stabilizer bar using light
chain with hooks or a cargo strap with a tightening ratchet.
9. Mark position of toe eccentric and rear suspension cross member for
reinstallation, remove the brake calipers and suspend with wires, and then
remove entire rear axle assembly. One list member left the trailing arms
connected at the front pivot, (toe eccentric), and just swung the suspension
assembly down out of the way.
10. Remove clamp bolt completely from the rear of the drive shaft.
11. Disconnect selector lever cable from the transmission lever and unbolt
cable housing from the case. Disconnect parking brake cable from the lever
next to the driver’s seat and pull out from rear.
12. Remove feed lines for ATF cooler and plug holes in case and ends of line
fittings
13. Pull off vacuum hose on modulating pressure box.
14. Disconnect control pressure cable on transmission by pushing small
locking bar of guide away from transmission and twisting guide in a
counterclockwise direction. Use cable housing to pull operating rod up and
disconnect from the cable.
15. Remove front and rear reinforcement plates from under the tube.
16. Lift transmission slightly and disconnect holding chain, (strap).
17. Remove cross brace over front of engine to prevent interference with the
oil filler.
18. Lower transmission only far enough that central tube/transmission
mounting bolts and control cable can be removed.
19. Raise central tube back to installed position, reinstall the rear brace
with two bolts and insert a block of wood to hold the tube in the installed
position.
20. Pull back transmission and lower. Depending on mileage you might consider
having new bearings and seals on the torque converter and new seals on the
axle shafts installed while the transmission is out.
21. Remove lower rear half of the flywheel housing cover plate.
22. Loosen the clamp bolt on the front of the driveshaft.
23. Lower tube enough to remove the clamps holding the ATF cooling tubes, the
vacuum line and the selector cable housing to the tube and the four bolts
mounting the tube to the flywheel housing.
24. Slide tube back to remove. Depending on mileage, you might want to remove
the flywheel and replace the rear main crankshaft seal.
I hope that I have got this all correct. Good luck.
Don Burrows
87 S4, A/T
300TE 4-Matic wagon
SECTION 5: Spring/Shocks
In a message dated: 3/16/00
OK, I’ve dutifully checked the archives and looked at all the websites, so now I’ll ask:
Is there any consensus on a good spring/shock (86.5)set up for a street (with some aggressive driving and maybe a driver’s ed or 2) 928?
I don’t want to lower anything (stock ride height is good) so should/can I go with aftermarker springs and shocks or stock springs/ aftermarket shocks. Do springs “wear out” as shocks do over time? Is there a way to test them?
Any thoughts on upgrading just shocks now, and springs later if needed? (Will I ever budget for that ring the SO is wanting lol)
Additional info if it helps: I don’t have wheel alignment or uneven tire wear problems (stock or close to stock tire/wheel sizes), but car tends to wander a bit on grooves, uneven surfaces, and feels a bit floaty, though subjective g-force rating still seems very good.
In a response dated: 3/16/00
Well, there may not be a consensus, but some of us have used the
Koni/Eibach setup. They are available from two of the Big Three.
Your 86.5 has adjustable spring perches on all four corners, so you can get
the new setup to the same height as before.
You’ll save lots of time if you can afford to do it all at once. (As far
as the ring goes, tell her it’s an extra eight hours work. Can she be
without you for one whole working day? Maybe you shouldn’t phrase it that
way.)
~Merry motoring~
In a response dated: 3/16/00
Just three words BILSTEIN, BILSTEIN, BILSTEIN After driving Chris Lockhart’s last wekk and remembering my previous bilstein experiences, I am even going to put them on my civic!! BTW, Ask DR at 928 Specialists about steroid treatment for your rear sway bar 1-770-928-4777 Later EIBACH
Regards
Greg Landwehr