Just a few general questions about the Manual Trans cars. I have been reading lots of stuff on the Mercedes Benz Automatics, but not much on the Manuals.

Did Porsche manufacture them?
Are they generally reliable?
What can I expect out of mine? (1988 S4)
Do they cross-reference or are they used in any other Porsches? 944?
Bascially, do they fail frequently, and if they do what are the options for spares and repairs?

Thanks for the discussion.

 

Ball cup, rear shift coupler bushings and reverle lockout spring are fail points.

And 5th gear if you are boosted or stroked.

 

1st and 2nd syncros are also prone to age/wear issues. Take good care of yours, there are not many left.

 

How many folks have broken 5th that were not racing with MEGA power?
I thought it was mainly just Mark A.

I will say that the difference in the feel of a 928 between a manual and a automatic is a stunning change.

 

Ive owned one for 100,000 miles and 12 years. The original gearbox was flawless with good synthetic gear oil. Same clutch from the day I bought it, too. I replaced the original a few years ago with the rare 89s4 gearbox with 2.63 rear end because I wanted the gearing. That has been equally reliable. To me, you couldn't ask for a better gearbox.

 

If you are racing with an on/off clutch then yes 5th gear is a weak link.
If you are on the street 600RWHP is ok depending on how you drive.

 

Not sure, just seemed common here but I suppose it may just have been Mark or on racecars!

 

I beat the living crap out of mine, not fast shifts, but a lot of full power starts.

 

I beat the hell out of mine too......
Quick shifts under boost, with a dual disc clutch.....

I really need to get going on new internals for these boxes.....

 

The reason that I brought up this topic, is that I used to be a 944/951 guy. In all of those years, I destroyed two gearboxes. Both from hard launches. Broken ring and pinions.

I am hoping that the 928 gearboxes are a little tougher.

 

If you're worried Roger can probably sell you a 4-speed clutchless shift upgrade kit :-) :-)

 

Not that worried. Just always wondered if there was a relationship between the gearboxes.

 

As far as I know, it's only the combination of 500+HP, racing clutch and slick tyres that cause the 5th gears to let go. Plus an agressive driving style....

 

I believe they are made by ZF.

 

I would be very interested in this, Colin!
Will you do several stages? And also a design that would handle quicker shifts? (not necesarily sequential).
Pls keep us updated on your progress.