JayJ911T

This thread is a perfect example of why working on your own car is a great thing. I was able to do a trans rebuild (1-2 crunching) and a top-end + some other reliability upgrades and a full re-seal for less than $3000 last year. Most parts were bought December 2006. I know pcar parts seem to jump up a lot every January as the dollar to euro is more "unfavorable". It might cost closer to $3500 if all parts were bought today.

The car has a 3.2L with a 915 trans. 2nd gear was crunching all the time, it was unusable on the track, and the engine was using oil and ticking even with a valve job. The car runs great, is quiet, doesn't use oil, and the trans shifts fantastic!

Here's a detailed break-down of everything I did:

Trans rebuild:

1st/2nd Slider: $190.00
2nd gear synchro ring: $77.20
2nd gear synchro hub (dog teeth): $126.04
2nd gear brake band: $64.00
2nd gear anchor stop block: $15.32
2nd gear anchor block: $18.50
3rd gear brake bands: $25.50
1st/2nd guide sleeve: $155.67
collar nut: $8.64
O-ring: $1.05
Guide Tube O-Ring: $1.70
Input Shaft Seal: $1.15
gasket, gear housing to case: $0.87
gasket, front cover to gear hsg: $2.15
gasket, cover plate for shift rod fork: $1.10
Swepco 201 (1 gal): $45.00
GruppeB Discount: $(35.27)
Shipping: $12.98
36mm Socket: $9.00
-----------------------------
TOTAL Trans Rebuild: $720.60


Top-End Parts:

Exhaust valves: $149.82
Valve seals: $24.60
Valve guides: $20.88
Valve Keepers: $10.08
Spring compressor: $0.00 (Autozone rental)
Rocker shafts + Hardware: $289.89
Re-Bush Rocker Arms: $348.00
ReGrind Cams: $275.00
Garrett Bros Machining: $336.00
-------------------------------------
TOTAL Top-End Mechanical: $1,454.27


Misc Top-End:

Complete engine gasket set: $243.42
Chain Ramps: $29.15
Cam Oil Lines: $51.44
Oil Return Tubes: $44.48
GruppeB Discount: -$29.04
RSR Rocker Arm Seals: $12.00
Exhaust hex nuts (6): $2.10
Exhaust barrell nuts (6): $14.52
Spark Plugs: $10.38
-------------------------------------
Total $378.45


Other Items:

Reference sensor: $77.32 (BMW equivalent)
Speed sensor: $77.32 (BMW equivalent)
Cyl Head Temp Sensor: $73.61
Engine Hoist: $150.00
Fuel filter: $17.95
Air filter: $11.79
Oil filter: $6.00
------------------------------
Total $413.99

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GRAND TOTAL TOP-END + TRANS: $2967.31
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It's great finding ways to save money on these cars. Using the BMW equivalent speed/reference sensor saves 50%. Oh yeah....go easy on the 1st -to- 2nd shifting.

theiceman

That's a great list Jay. When mine needs doing I am hoping to at least try it myself. I bought it as a project car anyway and with my tools and not using the car as a DD I think I could do it with the advice available here .. Even the advice that suggests some stuff should be left to a pro.

Peter Zimmermann

JayJ's post is good, however a slight terminology change should be made. Many years ago I learned of a Small Claims Court case (in CA) that made the distinction between the words "rebuild" and "repair." The court sided with the complaining party, because the shop involved used the terminology rebuild rather than repair, without considering the scope of the work actually done. Jay's rebuild is actually nothing more than a repair, with a minimal amount of work involved (even the 1st gear synchro ring was not replaced). The bottom line does show the possibility that trans work can be done for far less than the subject of this thread, but the work outlined by Jay falls far short of what is typically required in order to make a 100K mile + 915 last at least another 100K miles following a repair, which I believe should be every mechanic's goal.

Amber Gramps

Pete, one of the claims from the seller of my car and according to the paper work my car got a new clutch and first and second syncros. I have been under the car several times as of late and see no signs of the tranny being open. Where would the tranny have heen opened or what would I look for to confirm the work? Tranny is working flawlesly now, but it really makes me wunder if it really got done.

Peter Zimmermann

Douglas: If that work was done at the very least the housing for the gear cluster should have been cleaned, even though the diff housing probably would not have been. If proper cleaning was not done, the gasket surfaces between housing sections should be visibly clean to be sure that no contamination could have entered the trans while work was being done. When this type of cleaning is done dirt is removed from about 1" of housing on either side of the joint, and the fastening hardware should be clean.

Amber Gramps

Thanks Pete, the diff housing looks untouched, that I know. did I say thanks for the LSD ?

Svaha

And I've still got a perfectly functional 915 transmission for sale, $1500. Someone should be able to sell their core and get back into a working tranny for only $1000. What a deal!
Mark

JayJ911T

I guess not knowing the history (and how could one, since I didn't state it); it's difficult to say that my trans won't last another 100K. The car was bought with a "rebuilt" 915. The P.O. then installed a ridiculously modified 3.6L (currently has a 3.2L). I'm speculating there was a lot of "stoplight racing" involved. My trans, as most people here (again speculation based on forum topics), 2nd gear was pretty rough. Additionally, I had trouble getting the shifter into first when at a complete stop. So, upon opening the trans, I found a worn 2nd gear synchro, and what looked to be a 1-2 hub and 1-2 slider that wasn't replaced during the previous "rebuild". So, anything with very minimal wear (e.g. 1st + 3rd gear synchro rings which I flipped) wasn't replaced. I didn't charge myself to flip the synchro rings. 2nd gear was worn (abused) enough to where it was not a good idea (in my mind) to flip it, even though it was likely installed with the 1st and 3rd gear rings during the last rebuild/repair.

Will it last another 100K? Mechanically, why not? This thread shows "your results may vary" (read: the driver's shifting techniques). I also got rid of the horrible Weltmeister short shifter (useless for tall people), replaced shifter bushings, and adjusted linkage. These are all line items on a repair shop's invoice. Again, I didn't charge myself for this either.

A lot of people here are "repairing" work that was partially done, or perhaps done incorrectly from a previous owner and doesn't necessarily require a repair shop "rebuild". Pardon the oxymoron.

Brads911sc

Like 99% of the topics on this board... The answer you get... depends on who you ask... the true professionals would do a 15k rebuild on every engine and a 7k rebuild on every transmission and state that anything less isnt a "true" rebuild but a "repair". I would disagree. Replacing worn out parts is by definition a rebuild. Replacing parts that arent worn out is what the professionals want to do... but doesnt make it any more of a rebuild. Just my humble opinion. If I bought a car in which every worn part was replaced.. Id be fine with it called "rebuilt". Changing parts that arent worn out, dont make it last any longer...

Peter Zimmermann

Not to beat a dead horse, but if Jay posted that he had rebuilt 2nd gear, and merely flipped other synchro rings, that would have been perfectly acceptable terminology. So, Brad, you're obviously not privy to the agonizing decisions that a professional must make, on an almost daily basis, to protect his customer's bottom line. Professionals never replace parts that aren't worn out, but they know what the average life expectancy of every part is, and must decide if those parts will outlast the life expectancy of the repaired unit, or cut the life of that unit short. I can point to many examples of this, but it all comes down to amortization. How much per mile will it cost to replace those borderline exhaust valves, or put them back in, risking a premature failure?

A professional must not only repair the cars that he's been entrusted with he must also preserve his reputation. A DIYer has no such problem, and can do what he wants with his own car.

Let's look at JayJ's trans repair. The 1st gear synchro ring was flipped (as was the 3rd gear synchro). No professional would ever flip a synchro because it is not an acceptable solution. No micrometer measurements were given, but I would bet that the installed diameter, post flip of each synchro ring, was outside, larger than, factory tolerance. In the case of 1st gear the flip can work, but usually will have a drastically reduced life expectancy. The new 1/2 sliding sleeve will help, but it can only do so much. The problem is that the worn "side" (the outer surface of synchro rings is symmetrical) of the synchro ring allows for an installed diameter that's too large. When an unmolested synchro ring sits in position inside the synchro hub (dog teeth), which has tapered teeth, its installed dimension is a very precise 86.37 +/- .17mm (1st gear) or 76.3 +/- .18mm (3rd gear). A worn synchro ring, after being flipped, will not have sufficient friction material left on the surface that contacts the I.D. of the dog teeth, and that allows the synchro ring to expand beyond the specified tolerance. That condition exacerbates the wear to the friction material on the "fresh" side of the synchro ring, by the teeth on the sliding sleeve, until the synchro ring becomes smooth and the sliding sleeve can no longer compress it enough to effectively brake, stop, the gear.

Our 3rd gear situation is worse, because we have a flipped synchro ring mated to a used sliding sleeve. The worn teeth on that slider will carve away the friction material on the synchro ring, but even so it might outlive 1st gear because it is under less stress. If either gear is still operating properly after 30K miles I'll be greatly surprised.

On a side note, Jay posted on 2/12/07 that "the only special tools needed are the tools to remove/press the synchro hubs on...". Removal of 3rd gear, to flip its synchro, requires the holding tool (P 37 A), to lock the main shaft, as well as the special socket (P 252 A) to remove and torque the nut on the main shaft. During assembly the shift forks needed to be re-set, and the tool (P 260 A) would have been needed for that. So, without these tools, how was this job accomplished?

Now, Brad, the term "rebuild," in the context of JayJ's post, was used by Jay to describe what he did to his transmission, not what he did to 2nd gear. "Rebuild" means to build again, "repair" means to restore to sound condition after damage. This distiction may, on the surface, seem to be splitting hairs, but the words define two very different jobs, and two very different end results. In addition, your assertion regarding professionals is ludicrous. The professional is hired to protect the car's owner, not defraud him. Most pros that I've known, or worked with, had the customer's best interest at heart. Some were actually to conservative with repairs, which sometimes led to an uncomfortable mechanic/owner relationship. Your neighborhood professional might not be a good communicator, but he's probably a damned good mechanic, and knows more than you could ever imagine.

Ed Hughes

And that....is why I probably wont attempt to rebuild my own trans.....the engine seems a lot simpler, and straight forward to me. But when it comes to the trans, I think there is Black Magic going on inside there.

That, and I don't have the proper tools.

Peter Zimmermann

Ed: And you, sir, moved into "rebuild" territory with your engine - a perfect example of what I'm talking about. Sure, you re-used some components, but of the ones that can be considered "wear" items I'll bet they were well within allowed tolerances. You touched, cleaned, inspected and repaired as necessary every single piece of your engine, quite simply, you "built it again." And when you're ready to do the trans, that also will be rebuilt, Black Magic and all...

Brads911sc

Thanks Pete for your post. I never meant to question you as a professional. I appreciate your explanation and justification. You are correct that my comfort level is one of changing the brake pads, spark plugs, oil, trans oil on a 911... I even take it in to Eurowerks for a valve adjustment (as simple as some say that may be)... I also wont ever be rebuilding a trans. Just way too complicated for my skill level. I have rebuilt old VW engines, guess there is something intimidating to an ametuer like me about a 911 engine. Thanks again for your explanation. Made me think of things I have never contemplated before.

Brad
83 SC

Scott98

FWIW, I recently had new 1st, 2nd, 3rd and 4th gear synchro rings put into my G-50. Total cost parts and labor was about $1,500 - and that included me bringing the transmission to the mechanic and reinstalling it myself. Labor was 10 hours for $820. Is that inline with what other people are paying on a G-50?

Scott

Peter Zimmermann

Brad: When I read your post (#99) I realized that I might have left some loose ends in this thread - you just never know what different readers are thinking, and I wasn't even going down the road that you went with your post. Thanks for the reply, I'm glad that my post cleared up a few things for you...