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I finally got my rebuilt transaxle installed, but the shifter is exhibiting behavior which I'm having a hard time understanding. It was rebuilt by a highly reputable shop, whose name I don't want to mention, because I don't want to damage their reputation my giving the impression they did anything wrong, and they are trying to help me figure out the problem. When I first drove it earlier today for the first time after completing the torque tube replacement/trans rebuild project, it shifted reasonably well, although I immediately noticed that the feel of the shifter was different than before the R & R. The car has a short shift kit of unknown origin (installed by the PO before I bought the car way back in 2004), and it had a very notchy, though direct and precise feel, with very short throws, which I liked. Now, the throws were inexplicably noticeably longer, and not nearly as notchy, but at least I was able to shift through the gears, at least initially. But after just a few miles of driving, it became difficult to shift into second, and the difficulty quickly spread to all the gears, making it very difficult to drive, but I managed to get it home. I checked to tightness of the M8 bolts attaching the shifter to the torque tube, and they're fine, and I also checked to see if the shift rod had come loose from the linkage at the gearbox, but that connection is also solid. I don't think it's a clutch issue, because the pedal feels completely normal, and it was shifting OK initially, and I don't think a clutch would go from working normally to almost completely failing in a matter of minutes. So I contacted the shop who rebuilt the gearbox, and sent them some pictures of the linkage, as shown below:
He thought the M6 bolt at the end of the red arrow in the top picture might not be fully engaged onto the rod that it's supposed to be holding, allowing the rod to slide as I was attempting to shift into the various gears, which would explain my symptoms. So I removed this bolt, and tried to move the aluminum plate (which I assume is part of the short shift kit) to attempt to line up the opening in the rod better with the M6 securing bolt, but I can't get the plate to move relative to the rod, whether the transmission is in neutral, or in a gear.
Does anyone have any ideas what might be going on? Should I remove the short shift kit to get a better look at the parts? If so, how exactly do I go about removing it? If my short shift kit is somehow defective (which would be odd, because it was working fine when I sent to transaxle out for the rebuild), can anyone recommend another short shift kit for these cars that you are happy with? I've only driven one other 968, and was appalled at the length of its shifter throws. This is primarily a track car, so I really enjoyed the short throws I was getting before the rebuild. By the way, there was nothing noticeably wrong with the transaxle - I just sent it out for a rebuild because I had to remove it to rebuild my torque tube, and with over 130,000 hard miles, I figured it was due. Thanks.
I can't help you troubleshoot what's going on but I can tell you that the only944.com short shifter is pretty nice. It's not listed as fitting a 968 though, so this may be one of those areas where the S2 and the 968 differ significantly.
Underneath that rubber boot is another attachment point from the shift rod to the linkage on the transmission, to check tightness. On the bolt you have an arrow pointing at, it should have a tip/point to it and I find that if I move the linkage back and forth on the shaft while I turn the set screw with point you can sort of feel it engage into the dimple on shaft and once I get the point engaged in the dimple on shaft by hand then Im confident to tighten up with wrench. Even when tightening with wrench I find that Im trying to wiggle/move back and forth the linkage piece to get proper engagement before things bind and get tight. (that may all be brutally obvious but wanted to say out loud) Once the point is properly engaged in the dimple on shaft and you tighten up there should be no possible play or movement. Most of these pointed set screws have blue lock-tite on them as well. YMMV
Thanks for the reply. Yes, what you're suggesting is what the shop who rebuilt the transaxle recommended as well. I removed the bolt the arrow is pointing to (it was very tight), and yes, it has a point on it which is clearly intended to fit into a hole in a rod. The threads on the bolt are in fairly bad shape, so it lookls like somone somewhere along the line tried forcing it. But when I tried pulling and pushing laterally (in and out) on the aluminum plate through which the shaft that is supposed to be secured by the M6 bolt, I couldn't get the plate to move relative to the shaft. In other words, I wasn't successful moviing the rod the M6 bolt is supposed to seat into to get it into the proper position. It didn't make any difference whether I was in gear or in neutral. Am I doing it correctly? Also, does it look to you like the M6 bolt is fully engaged in the aluminum plate? The trans rebuild guy thought it looks like too many threads are showing for it to be fully engaged, and if it isn't, this would explain my symptoms. It was definitely very tight, so I'm puzzled how everything worked perfectly before, and it somehow popped out of its intended spot, which staying very tight. If you think it would be easier to walk me through the procedure by phone, please send me a message, and I'll give you my phone number. Thanks.
I sort of agree with the comment by your rebuilder, it does look like too many threads showing in the picture but considering this is an aftermarket piece its threading into its also hard to say if they have additionally supplied a longer set screw.
1 Your lever the set screw goes into looks thicker than the typical factory Porsche steel version.
2 If its the same factory set screw and the lever is thicker you would expect to see fewer threads.
3 You may need to remove your set screw, remove aluminum lever with small puller to clean up threads.
Pics of factory stuff below for your comparison. May need to run a tap through to clean up your threads. Occasionally remaining locktite red/blue can cause stiff threading/mis threading.
That's very helpful - thanks. A friend also suggested shooting a video of the linkage assembly while moving the shift lever through the gears - I'll do that as well, and try to post here, although I've never tried posting a video on Rennlist before.
Take the video, upload it to youtube and then just use the "share" button on youtube and it will give you the URL for the video, just post the URL and the forum software will make it an embedded video in the post. If you don't have a youtube account, you just need a gmail account and sign in.
OK, I think a major part of my problem is pretty clear - my set screw is quite mangled compared to yours:
It doesn't look like its tip has been submerged into the hole in the rod - and yet it shifted fine before I sent it out for the rebuild. I will order a new set screw on Monday, and will try to take the short shifter components off this weekend to get a better look at the rod the set screw is supposed to secure - I hope it isn't damaged beyond repair, because I'm sure the company that made my short shift kit is long gone.
I got the shift plate out, and fortunately the threads that the set screw screws into are in excellent condition, although it's a little hard to tell from the picture below:
But looking at the rod that is supposed to be secured to the above lever with the set screw, it's clear that the set screw was not seated in the dimple in the rod from the nicks around the dimple:
So it looks like all I need is a new set screw, and I'm in business. The odd things are that it shifted fine before I sent the transaxle out for its rebuild, and that the set screw was so tight in the lever, despite only being threaded in a couple of threads deep. What must have happened is that the set screw backed out, and then was jammed into place from the act of shifting, which also damaged the threads. Maybe it's just a coincidence that this all happened at the same time as I sent the trans out for a rebuild. Thanks for all the help troubleshooting this problem.
That did the trick! Finally completed the torque tube replacement (thanks to Isaacsracing for building me a new solid one out of a 944 TT, and to Black Sea R & D for installing their super bearings and heavy duty drive shaft) and transaxle rebuild (expertly done by Bill Rader Motorsports) that I started, with many interruptions, back in November. It was a huge job, and one I hope never to have to tackle again (the worst part was dealing with that wretched coupler sleeve), but the end result is great - the driveline vibration I was experiencing is gone, the car is no longer destroying its engine mounts, and it shifts beautifully. I've booked a session at the local track on Saturday.
Will do, but there's a lot of rain in the forecast over the next few days, and because of the lack of much run-off room at the local track, they don't allow sessions when it's wet.
That did the trick! Finally completed the torque tube replacement (thanks to Isaacsracing for building me a new solid one out of a 944 TT, and to Black Sea R & D for installing their super bearings and heavy duty drive shaft) and transaxle rebuild (expertly done by Bill Rader Motorsports) that I started, with many interruptions, back in November. It was a huge job, and one I hope never to have to tackle again (the worst part was dealing with that wretched coupler sleeve), but the end result is great - the driveline vibration I was experiencing is gone, the car is no longer destroying its engine mounts, and it shifts beautifully. I've booked a session at the local track on Saturday.
05-13-2021, 01:40 AM
Strange (in a very bad way) shifter behavior
