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Transmission Linkage Slop

Posted: Tue Jul 12, 2022 6:00 pm
by Tom
I have an annoying vibration rattle that comes up through the gear shifter at certain rpms. Best I can tell, it's coming from the shifter rod (the one that runs back to the transmission). I've disassembled the shifter and have a nice new nylon bushing at the base, and greased up the peg where the rod attaches to the 5-year old shifter, but the noise is still there. I'm inclined to replace the linkage on top of the tranny, as I can get a metal on metal noise by moving it around. It shouldn't be this loose, right?



Re: Transmission Linkage Slop

Posted: Tue Jul 12, 2022 7:32 pm
by Zirconocene
Agreed that it should not be that loose. It looks like there's some slop in the nylon bushing thing but my memories of my transmission work are in the distant past.

ETA: I was watching the video on the only944 site (https://only944.com/partscatalog/only/shiftlinkagearm/) and a couple of things stood out: There's a nut on the backside of that nylon bushing, can you tighten that up a little bit? Even the old, nasty thing they show on the video doesn't show the lateral movement of the bushing that you highlighted. Perhaps it's just that you were moving it laterally intentionally, but the really old part in the video looked pretty stable.

ETA^2: My S2 also has the short shifter from only944 installed, so I eliminated that nylon bushing, which may be why my memories of it are hazy. It's a nice piece to tighten things up. If you don't want a shorter throw, perhaps there's a way to keep that stock with those parts.

Have you considered the only944 shift linkage arm, as well, if you're going to do some work back there?

Good luck

Re: Transmission Linkage Slop

Posted: Tue Jul 12, 2022 8:42 pm
by Tom
Zirconocene wrote: Tue Jul 12, 2022 7:32 pm Agreed that it should not be that loose. It looks like there's some slop in the nylon bushing thing but my memories of my transmission work are in the distant past.

ETA: I was watching the video on the only944 site (https://only944.com/partscatalog/only/shiftlinkagearm/) and a couple of things stood out: There's a nut on the backside of that nylon bushing, can you tighten that up a little bit? Even the old, nasty thing they show on the video doesn't show the lateral movement of the bushing that you highlighted. Perhaps it's just that you were moving it laterally intentionally, but the really old part in the video looked pretty stable.

ETA^2: My S2 also has the short shifter from only944 installed, so I eliminated that nylon bushing, which may be why my memories of it are hazy. It's a nice piece to tighten things up. If you don't want a shorter throw, perhaps there's a way to keep that stock with those parts.

Have you considered the only944 shift linkage arm, as well, if you're going to do some work back there?

Good luck

Thanks for all that. I'm going to order the factory nylon part from Marin Porsche (they seem to be the new price leader), and will definitely give the only944 linkage a try. Thanks for that link. :) For $30, it's worth a try and will save me from looking up and ordering all the little bits that make up the original.... :)

Re: Transmission Linkage Slop

Posted: Thu Jul 14, 2022 8:46 pm
by cda951
I normally don't like short shifters, but the Only944 shift linkage is one of the best modifications I've done to my 951.

A slight bummer was the pivot bolt atop the trans case snapped removal, so I had to drop the transmission to drill it out. Luckily I was working on a lift at my shop, so it was a quick process and I also replaced the weeping input shaft seal at the same time :)

The Only944 shifter and filling the voids of the factory trans mount with 3M window weld urethane truly transformed the driving experience. I still cannot believe the difference that was made by the latter "mod."

Re: Transmission Linkage Slop

Posted: Fri Jul 15, 2022 6:25 pm
by Dave W.
Thanks for the vid. I checked the freeplay in the linkage on my spare trans and it seems to be nearly the same. Just in case the new nylon block doesn't eliminate the freeplay it might help to add a thin shim. The pivot shaft is 10mm and the OD is 25mm. Here's an easy way to add a precision shim; https://www.suspensiondirect.com/shop/klv101525
The dimensions given on that site are metric, so 0.15mm shim is just 0.006" thick.

Re: Transmission Linkage Slop

Posted: Sat Jul 16, 2022 5:38 pm
by Tom
Well... hmmm.... I ordered the new nylon linkage part and should get it in about a week. In the meantime, I may have found the actual source of the rattle/vibration.

I had the shifter off as I was searching for anything that may be rattling under the boot. Today, I decided to put the gear shift back together in the cabin. I had looked at every little bit a 100 times over the last few weeks, but suddenly it dawned on me. The metal shift lever was backwards. The pin on the side of the shifter was pointing toward the driver side, not toward the passenger side like it's supposed to be. I didn't even know it would work that way, but it seemed to shift fine. Only thing I can figure is that the upholstery shop inadvertently flipped it when they made my new leather boot.
Not sure why they would have taken the linkage off, but probably just figuring it out as the went.

When I realized that, I turned it back around and put it all back together and -- no more rattle. I'm guessing the shift rod was too far to the driver side and was rubbing or hitting something.

Since I have the new linkage coming for the rear, I'll put it in anyway, but the rattle is gone and the shifts feel good, so I "think" that issue is solved. :)

Re: Transmission Linkage Slop

Posted: Sun Aug 28, 2022 4:57 pm
by Dave W.
Tom wrote: Sat Jul 16, 2022 5:38 pm Well... hmmm.... I ordered the new nylon linkage part and should get it in about a week. In the meantime, I may have found the actual source of the rattle/vibration.

Since I have the new linkage coming for the rear, I'll put it in anyway, but the rattle is gone and the shifts feel good, so I "think" that issue is solved. :)
Hi Tom,

Any feedback on the nylon block? I'm curious if a new block tightened the freeplay?

Re: Transmission Linkage Slop

Posted: Sun Aug 28, 2022 8:27 pm
by Tom
Dave W. wrote: Sun Aug 28, 2022 4:57 pm
Tom wrote: Sat Jul 16, 2022 5:38 pm Well... hmmm.... I ordered the new nylon linkage part and should get it in about a week. In the meantime, I may have found the actual source of the rattle/vibration.

Since I have the new linkage coming for the rear, I'll put it in anyway, but the rattle is gone and the shifts feel good, so I "think" that issue is solved. :)
Hi Tom,

Any feedback on the nylon block? I'm curious if a new block tightened the freeplay?
I have the new part but haven't put it in yet. I got distracted by smog (I passed). Stay tuned, I'll put it in shortly and report back. I think the vibration was due to the shifter facing the wrong way, which I choose to blame on the upholstery shop. ;) While getting ready for smog, I noticed the Tail wastegte is very close to the TT and may be touching/vibrating, so I'll fix that too while I'm under there. My shifter isn't 'that' sloppy, but I'll try to get a good sense if/how much the new nylon piece tightens it up.

Re: Transmission Linkage Slop

Posted: Fri Oct 21, 2022 11:50 am
by Dave W.
Update; I bought a new nylon shift block (edit) like the one in the video above and it completely eliminated all freeplay in the shift linkage. In fact, the new shift block fits a little tight, I had to push and twist to install it on the pivot shafts. It loosened up after a few miles of stop-and-go driving.

FYI I got it from from PartWorks. de Just search for artikelnummer 1266. The kit also includes a little packet of grease, new hardware and extra shims to eliminate any freeplay.

Re: Transmission Linkage Slop

Posted: Fri Oct 21, 2022 12:03 pm
by Tom
You mean nylon in the video above? I still need to put mine in.... if this is what fixed your slop, I'm suddenly motivated to stop procrastinating... :)