GregBBRD

Twenty years from now, it will still be too soon.

Amazingly enough, the original engineers knew that there was a potential for that arm to be "run through" the gears, so they put a snap ring on the shaft to retain it, in 1985. Of course, when the upper part failed and the spring needed to be replaced, that snap ring made life really tough, so I'm guessing that they decided to leave the snap ring out, because of this.

None of these pieces...beginning with their production in 1985 to the end of production in 1995, regardless of any of the supercessions, were some of Porsche's greatest engineering feats.
The number of ruined gears from this failure has to be mind boggling....certainly way, way more than all the belt failures combined!

Pete L

Update – installed rebuilt torque tube, replacement clutch disks from Rodger, transmission with Colin replacement centering spring and later model (1987) pre-selector rod and rear suspension with all new bushings and emergency brake pads. Took the car for a drive – Rodger's clutch disks even though thicker then factory did not drag, transmission shifted fantastic with replacement centering spring, engine ran fantastic (has Kens chips). But the noise I was trying to cure and was convinced torque tube bearings persisted - seemed to be mitigated 50% from previous - but very noticeable. ****

The growling occurred with transmission (G28-11) in gear but when clutch depressed, ceased. Back under car with stethoscope and seemed to hear the “growling” from input side of transmission. Pulled transmission again (getting darn good at this!) and took it to Greg Brown at Precision. My diagnosis, failing input shaft bearing.. Perhaps this had something to do with the torque tube shaft (see splines in photo) and harmonics from torque tube causing this bearing replaced

20 / 30 k ago to fail

Greg telephoned me on Tuesday after the Kyle tore it tear down and sent the photos of the input bearing and galling found on the race. My diagnosis was correct. He stated probably the worst he has ever seen. Thankfully did not damage any gear sets! Greg / Kyle / Precision disassembled and cleaned the entire transmission and differential (limited slip) and WOW what a complete review / inspection / diagnosis of my G28-11. Now doubt it will be returned to me in PERFECT order shorty. Precision will do the following work based on the diagnosis:

· 5th gear input bearing – see photo

· Pinion bearing – some wear, not failing but prudent

· Synchro on 1, 2nd almost at wear limit, replacing this Billet steel / carbon (Raush?)

· Couple of the needle bearings

· New limited slip diff discs

· Replacement carrier bearings in diff

· Set up pinion gear depth (necessary do to bearing replacement)

· Couple of thrust bearings

Looking forward to getting my transmission back and in the car so I can drive and enjoy it. Of course, will also take car down to Greg for alignment and a peer review of my suspension work after trans gets back in

Galled input bearing

GregBBRD

Now I understand why your 5th gear looks the way it does.

If you replace that shaft, install the counterweight in the torque tube with new rubber supports (this is what causes this damage) and get a new 5th gear clamp collar, your 5th gear will survive, for many more years.

Darklands

Germans say:"Der Teufel ist ein Eichhörnchen!" The devil is a squirrel!

Anything that can possibly go wrong, does.

Like Greg says, maintenance isn´t changing one or two pieces anymore , we must overhaul complete systems on the cars who interacting together.

Or driving a 928 is a sign of charakter, but you need on the long term the same deep pockets like driving a new/young Porsche sportscar.

Pete L

Greg Shaft was replaced. Mark Anderson was good enough to sell me one that was in good shape. Also replace the rubber on the mass damper. Can you explain why I should replace the lock collar. Thank you

GregBBRD

The OD of 5th gear has some wear, as well as the ID of the clamp will have. Because this is a harmonic issue, from the counterweight rubbers deteriorating over time, this wear is not equal in all areas, but will vary from areas with high wear to areas with almost no wear.

While there is nothing I can do to correct 5th gear, I believe a perfectly round new collar, in an effort to get the best possible clamping, is a positive thing.

Pete L

After two years of rarely driving my early 86 it is again - at very long last – on the road. Want to share the story

1. 5 years or so ago, centering spring broke and shifter was sloppy - my early 86 had a unique spring

2. Took out transmission, suspension, torque tube , clutch 2 years ago, post 1

3. Rebuilt torque tube – thought that was the cause of the growl I was hearting. . Parts from Rodger and Mark Anderson, thanks!

4. Nope, darn growl from input bearing – see post #17With Torque tube work replaced clutch disks (aftermarket from Rodger, work fine even though a bit thicker, just adjust intermediate plate correctly), throw out bearing, ball cap, etc.

5. Torque tube shaft was galled, see post 17, replaced it (Thanks Mark Anderson)

6. Replaced centering spring with Collins replacement spring as well as pre selector lever used form 87 up (modifies shift plane to center into 2/3 gear which is different from 85 / 86 boxes) see posts #1 – 13. Thank you Greg B for advise / consul / coaching

7. Rebuild half shafts – thanks Rodger

8. Replace right side wheel bearing – bought a 20 ton press

9. Replaced all rear suspension bushings – thank you Rodger, Carl F, Mark Anderson

10. Replaced original rear emergency brake pads - what a PIA

11. Installed the replacement coupler bushings for shift rods – thanks Rodger

12. Reassembled all (clutch, torque tube, transmission, suspension) and

13. that growling noise is still their – shi………………………..

14. Remove exhaust, rear suspension and transmission again, take to Greg Brown and Kyle at Precision

15. Precision refreshed gearbox to perfection including new 5th gear, input bearing, limited slip clutches, synchronizers on 2nd, 3rd (carbon type recommended by Greg) etc., see photo and posts by Greg.

16. Installed a new collar between torque tube shaft and transmission per Greg Brown

17. Reassemble / reinstalled transmission

18. Darn battery dead, will not charge, new battery installed

19. Darn positive batter post connector on car cable pulls off – replace it

20. Car starts on first try

21. Result – it’s a new car shifts fantastic! No darn noise click click click

22. Next step – align

Victory - thank you so much 928sRus, Precision, 928 International, 928 Motorsports and Colin


REAR SUSPENSION OUT FIRST TIME

REAR HUB, ONE NEW BEARING, NEW E BRAKE PADS

TRANSMISSION OUT AGAIN

NEW G28-11 PARTS 5TH GEAR, INPUT BEARING, LS DISKC, NEEDLE BEARING, SYNCHRONIZERS

PORSCHE DISK VS AFTERMARKET DISK

BACK IN AGAIN, NOT THE BEAUTIFUL CAD PLATED FASTENERS AND BLACK OXID COATING BY PRECISONON OUTPUT HUB

DONE

COMMING HOME FORM PRECISON

BACK IN

GregBBRD

My dad always said it was better to be lucky than good....
But since the only luck I have is bad luck (my goal, when buying a Lottery ticket, is to get a $2.00 winner.....still buying and hoping),
I had no choice but to be good.

Happy that it works!

Darklands

Nice transmission stand!
Greg, all looks like new!

RennHarry

Pete, really nice work. I know you gave special props (of course) to all the wonderful vendors and experts that helped you, but you should really take a bow, in addition to your victory lap.
Cheers