I just noticed a shudder in the driveline that appears only under heavy acceleration. It goes away immediately after lifting the pedal again and does also not appear when gradually accelerating, so it's not connected with speed it seems.

Could this be the dreaded Torque Tube issue?

Piet
87S4 AT

 

Piet,
Just some random shots, for I have no answer: Firstly, the serious issue of "dread" would be the thrust bearing - and I'm sure you had done the pinch bolt release/crank end float or free play measure; therefore, that would not be an issue.
Some things that come to mind under your conditions would be loose rivets in the front flex disc: some early '87s had rivets that that came loose and created problems - they were later replaced by bolts. Bad TT bearings should be noticible at lower speeds; however, if the rubber TT bearing support failed, there may be vibration when pushed hard. Loose pinch bolts, front and rear may be an issue, torque convertor bearings beginning to go, ... just guesses ...

 

Just had this same issue with my 951.

Needed new half shafts.

 

Here's what I'd check in order:

1. Half shafts
2. Driveline mounts (transaxle, engine)
3. Rear suspension points (weissach, bushings)
4. Drive shaft pinch couplers.
5. Transmission

 

OK, thanks for the tips so far. Next monday I'll take it to the garage and i'll let you guys know what the outcome was.

Piet
87S4

 

Check the bolts on the halfshafts to the gear box.

 

Half Shaft
Engine miss fire,
Transmission chatter; slippage

 

Hey, Steve - welcome back!

 

Hey, Randy

I never left, I was on a sabbatical

 

any update on this issue? I'm experiencing the same thing, but it comes and goes.

 

Piet,
Check for loose seat mount/rail hardware.
Sometimes, under hard acceleration, when your butt puckers-up real fast and your wallet has one cheek or the other raised slightly higher than the other the seat shudder will develope.
Hey, Steve...

 

Kraabel, never got to the bottom of it because the problem just went away and I didn´t want the shop to spent time hunting possible problems down. It´s still not exactly a smooth car but most of that is probably due to it needing new motormounts. And the intake removal and repair. And.. Sigh.
After the summer I´ll have a garage at my disposal and can start tackling these things. Finally.

John.. I like your suggestion, my wallet is usually filled with half a kilo of loose change and no notes to dampen it. So

Piet
928S4 '87

 

IT WILL COME BACK AND HAUNT YOU!!!
OK not so serious, but this might be a problem with your TT(yep, the dreaded one).
When you take time to check your TT, check also (almost mandatory based in your symptoms) the rear flex plate and torque converter. You have symptoms of a slipping tube that does not engage properly at all times, the problem went away because the tube catch enough on either end to keep transmitting power form eng. to gearbox. Eventually it would come back (specially of you drive on an inclined road)....
OR in the other hand, it could just be your plugs/cables...one or two might be already too old and losing some conductivity....

 

And don't I know it My other plan is saving up some €€s and buy one of the near perfect examples in the US and keep my 87 for restoration, that's what it would really be in the end.

Piet
87S4 '87
Peugeot 205 Diesel