westija

'89 928 S4 5 speed

I finally have tried to inspect my transmission shifter coupler plastic/nylon bushings to find the cause of the wobbly shifter (I posted on this thread a while back https://rennlist.com/forums/928-foru...e-trans-4.html).

Well, the front one (behind the clutch housing on top of the Torque Tube), I can barely see, so, no way to inspect that without major wrenching, I suppose.

On the rear coupler I found that there seems to be a piece of the bearing missing, since the shifter mechanism has so much play inside the coupler. That is the first picture below. It does not even look like some pictures I saw around here (please see third picture of one I am referring to). I believe I have to replace the entire coupler (part number 928 424 029 00 - item # 2 on the parts manual below). Please see below and let me know your thoughts.

Given that the front one seems so inaccessible (like everything 928) and requires to drop the exhaust, I am almost thinking to take it to a shop. But before I decide, I would appreciate some tips:
There are quite good write ups on jenniskens http://jenniskens.livedsl.nl/Technic...5/MyTip579.htm). Can the exhaust be put back on my own or is it too heavy for one person? If I do it, do I need to replace the exhaust nuts/ bolts as well or can I reuse them? Do I need to use some paste to seal the exhaust tubes when putting it back together?

Thanks in advance

depami

I changed the front ball cup on my '82 with exhaust in place. Creative use of multiple pry bars to remove with varying difficulty depending on how bad it is; a lot of cussing to wrench the old one off and the new one on; strap clamp or large hose clamp to pop the new one in place.

Likewise, the rear bushings can be replaced without removing the coupler entirely.

jheis

You are missing the bushing(s) from the rear coupler. You can get Delrin replacements from Roger at 928srus. You'll need a press to press the center portion out, then replace the bushings from the inside of the housing and then press the center piece (pin) back in.

You'll know when the front coupler goes bad because it will pop off leaving you with a box full of neutrals. Mine failed in the middle of an intersection in San Francisco....

The front coupler can be replaced in situ, but it requires some ingenuity (and some creative cursing). You'll need a stubby 19mm wrench because of limited clearance. I cut down a 3/4" (19mm) open end wrench - you can slip the box end of another wrench over the end for increased leverage.

GregBBRD

It's actually a 17mm nut that locks the front coupler down.

jheis

Greg is correct (my recollection was that it was a 17mm, but when I grabbed the cut down wrench from my tool bag it was 3/4" (19mm) soooo, I assumed that my memory was faulty - must have cut this one down for some other purpose).

GregBBRD

If the rear bushings are gone....the front coupler usually isn't very far behind.

Pretty simple to get someone to sit inside the car and gently move the gear shifter back and forth, to see how much slop there is, in the front ball cup.

That's how we determine the amount of wear, here.

westija

Finally had the time to finish this job.

I have to say that out of all the repairs I've done in the car to date, and I can say that I've done quite a lot , this one is topping the list in terms of improvement per $ and per hour spent. Awesome difference in shifting

Got the bushings from Roger at a great price, had a friend press the shaft out and press it back in with the bushings and spent maybe a couple of hours to disassemble and reassemble it in place.

I have not done the front coupler bushing yet, although I suspect Greg is correct that it's time to do it , but it is pretty hard to access. I am "saving" that for a moment of boredom

If any of you have not done this yet, check your rear coupler for play and I seriously encourage you to do it.

Thanks everyone for the help

17prospective buyer

Can you remember if the selector shaft (the one that goes into the tranny) itself was threaded for the set screw that goes in there? I failed to get mine removed so now it's become part of the shaft and i just drilled a new hole just slightly off center from the screw that is now jammed in there. I'm hoping the coupler slides back far enough for a new set screw to engage the "new" hole i drilled but still far enough forward for the clamp to engage properly.

Vilhuer

Its just blind hole which narrows down. No threads.

17prospective buyer

Even better! Thanks.

westija

That is what I thought too. The conical end of the @#%$## screw gets in the blind hole and keeps everything tight.

WallyP

This might be a good time to repeat an old post...

If the front shifter cup pops off of the ball, leaving you away from home with a non-functioning shift lever:
- Grab the shift lever with both hands - one low as possible, one on the ****;
- Rotate the lever so that it is positioned in the center "slot";
- Push firmly forward with both hands.

If done correctly, you will now be in third gear, which is low enough to get going with minimal clutch abuse, and high enough to drive a reasonable distance at reasonable RPM.

cschou

Just out of pure curiosity, with the delrin bushings in the rear coupler, do you get more vibrations from the gearbox into the gear stick?
One could expect the less elastic delrin to transfer more vibrations...

Thanks,
Casper

Dave928S

I haven't found the delrin to give any more vibration.

Mike Frye

rear shift coupler+front shift ball cup+release arm ball cup (top of trans, behind air cleaner) are the three bushings that wear in the linkage. If one is worn out, they all are.

IMO, as the motor mounts start to compress and the engine sits lower, it allows a lot more heat to be sent into that tunnel which accelerates the decay of these last two. They wear and get heat soaked.

Whether this is coincidental or causal doesn't much matter though, they are all wear items and part of a refresh to make the car run and ride smoother.