andy boardman

Morning / Evening ....whatever

I have had a whining noise from the transmission tunnel followed by the growly / loud whining noise followed by the tinkling / graunching noises from the tunnel followed by very little noise over the last 1,500 miles - I guess this means that at least one of the three bearings in the torque tube has now disintegrated!
(reason for the full gamut of noises etc was I have been in France travelling for much of them and unable to stop and do anything about it!)

Anyway now I have to change the tube - I have located a rebuilt service exchange item in London for 50% of the cost of the item ex Porsche GB or Porsche France (no surprise there) and I have read with interest Tony's write up on the changing of the item (also Ketchmi's write up of the rebuild of the unit itself). What I really would like is a definitive list of what else I need to arm myself with to fix whilst 'in there'.

So far I have:
a) Torque convertor bearings
b) O2 Sensor (mine has 105K miles on it so probably due for change?)
c) Transmission filter and fluid (changed 5,000K miles ago so should be OK)

What else? Gaskets, thrust bearing ??

All help much appreciated - I use my 928 as a daily driver (17K miles in last 12 months) so any down time has to be minimised.

Thanks...........Andy

Thom1

Hi Andy,

My mechanic and I should start on the job tomorrow. Here is what I have found so far:

Thom’s Torque Tube Essentials (UNDER CONSTRUCTION):

Applies to 1986.5 928S3, USA, Automatic

Just when I thought I had it about right mechanically… that new noise has been diagnosed as torque tube bearings… kinda’ like a grrr… rpm dependant… more obvious noise inside the car, than when listening under the hood.

PROCEDURES - REMOVE:
1. Exhaust. System – From back of headers to all the way back
2. Rear Suspension
3. Transmission
4. Torque Tube (TT)

PARTS FOR 1986.5 US AUTO:
1. Rebuilt TT, $495
2. Torque Converter (TC) Bearings (2), $43, 900.052.122.00
3. Transmission Fluid –Mobile-1 (8 quarts), $40
4. Transmission (A/T) Filter Kit, $37, 960.307.901.01
5. A/T Main Pump Gasket, $6, 126.271.128.0
6. A/T Main Pump Sealing – Inner (2), $7, 126.272..095.0
7. A/T Main Pump Seal – Outer, $9, 010.997.474.7
8. A/T Main Pump Sealing – Inner – Large, $4, 016.997.144.8
9. A/T Vacuum Modulator/Actuator, $28, 126.270.927.9
10. Exhaust Manifold Gaskets (2), $6, 928.111.127.02
11. * Exhaust to Header Bolts – M8x35 and Nuts - M8 Locking (6 each), or use nut and lock washers
12. Rear Main Engine Seal
13. Brake Fluid – Super Blue Racing ATE
14. CV Boot Kits (4), $60, 928.332.924.02
15. CV Bolts (12), $14, 900.067.123.01
16. Brake Cleaner (3)
17. Mineral Spirits
18. Paper Towels
19. Blue Nitrile Gloves
20. Loctite – Medium Strength
21. TOTAL PARTS ACCOUNTED FOR SO FAR, $749
22. Shipping: $167
23. Tax

OPTIONAL PARTS:
Rear Brake Pads
O2 Sensor, $113, (needed every 60kmiles. Do not do now.)
Parking Brake Shoes, $120 (No. Too expensive, and good enough condition now)

CONCERNS AND PROCEDURES:
1. Dave Roberts advised to pry the crankcase (or crankshaft?) toward rear with a crowbar before final clamping. Watch the X dimension at the flexplate. Determine that only about 4mm? (see Tony’s site) of splines show before TC pinch collar. For complete procedures, See: <a href="http://members.rennlist.com/v1uhoh/torque.htm" target="_blank">http://members.rennlist.com/v1uhoh/torque.htm</a>
2. Tom at 928 Int’l advised to check seating of TT bearings. They can be disturbed during shipment.
3. Return TT with undamaged splines to 928 Intl, plus TC bearings
4. Inspect Flange Rivets on the Torque Converter
5. Rear Main Seal – do it while exposed. Use grease for easier installation.
6. If you remove your engine or transmission make absolutely sure that you adjust the pinch clamps on the torque tube drive shaft (according to the workshop manuals). Mercedes Benz issued a tech bulletin on torque converter ballooning. They want you to lay down the torque converter on its primary pump flange (hub) and measure from the work surface to the top of the flywheel mounting ears. If it’s more then 121.5mm, the torque converter has ballooned and needs to be replaced. See:http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=14&t=002711
7. Cleanup CV joints: Clear Large Storage Box, Cardboard, Paper Towels, Shop Towels, Brushes, Squirt Bottle, Spray Paint, dishwashing detergent, garbage bags. Mineral Spirits, Brake Cleaner, MEK, or Acetone?
8. medium grade Loctite on CV Boot Bolts
9. Mark CV orientation before removal. Install with same orientation.
10. Sheet metal cutters, hex keys, sharp pick, and tin snips for removing and marking CV boots. CV clamp tool or nail remover works. Circlip Pliers, Torque Wrench, Gasket Scraper, Hammer, camera
11. Put a nozzle extension on lube cap. Allows easier access to recesses.
12. Put dishwashing detergent inside boot lips for easier installation
13. Put on required clamps loosely before installing boots or joints.
14. Groove on the CV joint goes to the far end of assembly on the circlip side.
15. Intall the rubber boot on the clamp flange first. Then slip on the large band clamp and crimp it on. Slip the assembly on the axle, small end first then slip on the newly greased CV joint making sure the groove is on the outer end. Attach new clip from the kit. Slide boot flange to the CV body and loose fit all 6 bolts. Now crimp on the small end band clamp. Repeat steps for other end of axle. Voila - new rebuilt axle ready to reinstall. Bonus - Paint the stripped axle and both boot clamp flanges with some flat black paint prior to reassembly. Make sure you mask off the ends ot the axle and the boot seat on the flange. Dont forget to assign an axle end and scibe an x on it. I chose my x to be the transaxle end.


Another option is to rebuild the TT See:
<a href="http://home.attbi.com/~gq-beej/928/ttrebuild.htm" target="_blank">http://home.attbi.com/~gq-beej/928/ttrebuild.htm</a>

See links below for TT discussions:
<a href="http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic&f=14&t=002597" target="_blank">http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic&f=14&t=0025 97</a>

<a href="http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic&f=14&t=001415&p=" target="_blank">http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic&f=14&t=0 01415&p=</a>

<a href="http://www.ejs-has.symbiotix.com/Porsche_928S4/Slideshow4.html" target="_blank">http://www.ejs-has.symbiotix.com/Porsche_928S4/Slideshow4.html</a>

<a href="http://members3.boardhost.com/928s4vr/msg/22314.html" target="_blank">http://members3.boardhost.com/928s4vr/msg/22314.html</a>

CV Boot Replacement
<a href="http://www.928s4.com/project/cv.htm" target="_blank">http://www.928s4.com/project/cv.htm</a>
<img src="graemlins/burnout.gif" border="0" alt="[burnout]" />

andy boardman

Thom - many thanks - just what I needed! Be sure to let me know how you get on with it - especially fitting the seals for the main pump and rear engine seal.

I see you made no mention of the thrust bearing - any reason for this?

Andy

Thom1

Hi Andy,

Glad to help. Some people would not replace some items such as CV bolts. But, they are cheap.

What's a thrust bearing? Do you mean TC bearings?

The bearings that I am replacing are:
1. Rebuilt TT, $495 - contains 2 bearings
2. Torque Converter (TC) Bearings (2), $43, 900.052.122.00
<img src="graemlins/burnout.gif" border="0" alt="[burnout]" />

L_Snipes

Thanks for the replies concerning the noise coming from my 1990 S4. This morning after arriving at the office (no extraneous noises) I think the noise is coming from "mid ship" instead of from the rear (fuel tank rear). Torque tube? Any suggestions as to diagnosing the tube (bearings, etc). Am familiar with diagnosing typical drive shaft problems (US Vehicles). Owner for 4 months. Thanks.

Thom1

Hi...?,

kinda’ like a grrr… rpm dependant… more obvious noise inside the car, than when listening under the hood.

TO DIAGNOSE:
See above, and to identify source, use automotive stethoscope, or long screwdriver (press ear closed with screwdriver handle, and hold tip to suspected noise source). Put car on lift. Hear more intense noise along the TT area.

BTW, it is helpful to have a description of your car(see my signature), and friendly to use a first name.

HTH,
<img src="graemlins/burnout.gif" border="0" alt="[burnout]" />

atb

[quote]Originally posted by andy boardman:
<strong>

I see you made no mention of the thrust bearing - any reason for this?

Andy</strong><hr></blockquote>

Hi Andy,

The thrust bearing is located on the central crank saddle inside the engine. You can check for crank endplay to determine if your thrust bearing is still within wear limits. Because of its location deep inside the engine, it's not typically considered a "while you're in there" item, and would require a full disassemble of the bottom end of the engine to remove and replace.

I hope this answers your question. I believe Tony has an easy method of checking crank endplay at this V1UHOH site.

Good luck!

-Adam Birnbaum
'88 S4 A/T - Has had TT replaced twice

andy boardman

Thom - Adam - thanks guys - have arranged shop time with a mechanic friend of mine to sort this out at the end of the month - will let you know how I get on. (Adam - why TWO TT replacements - lots of miles or problems?)

Have read with interest the comments in archives and elsewhere on flexplate pressure etc I will be interested to see what happens to mine when we slacken off the pinch bolt!

In the meantime - thanks for the help.

Andy