I thought I'd post this here as I start my own research into the cause of the problem. Please respond if you have any ideas.
Background info perhaps pertinent to the issue: Cruising down the highway at 60-75 mph I now get periodic pop-outs of 6th gear. Sometimes it occurs in 2 stages. First a pretty violent forward movement of the shifter in the cabin and the car technically stays "in gear", followed by a final slip out of the gear a few miles later. Other times it is just a single step where the thing just comes out of gear.
My initial research showed that the motor mount could be the culprit. I replaced that but still get the problem. The motor mount rubber was completely cracked thru the center in a couple of places, so I thought I may be onto the cause.
I replaced the clutch about 6 months ago and drove on the highway for probably 4 months w/out this pop-out issue occurring. I have a B&M short shifter in it, which I installed in about 2010. There is quite a bit of side to side slop which I've been thinking about fixing w/ some metal bushings (Function First, I believe). The gear change cable on the side (forward/backward movement) ball and socket came apart several years ago and I used the zip tie "fix", which I did again when I replaced the clutch 6 months ago (130K miles). I've also thought about the upgraded metal socket replacement that has a couple of cotter pins that slide around the sides of the ball.
My son mentioned that perhaps the shifter cables moved when the broken engine mount allowed movement, and that they're now slightly out of position, which could put tension on the ball/socket connection and eventually pop it out of gear.
Anyway, feel free to ask any questions that I've not provided info for or if I have not been clear.
Thanks for taking the time to read this.
John T
I had the problem where 2nd gear would grind and pop out. This is a known issue with 987 transmissions and there are only two solutions - 1) catch it early and replace your 2nd gear synchro or 2) replace your trans.
Now, I have not heard of issues with 6th gear so could be something different. Also, shift cables go bad on these due to another known issue with the design of the shift linkage.
Porsche
has an upgraded linkage or you can replace the shift cables with
Numeric Racing cables
.
I like your son's diagnosis. I think it's likely that your cable is not fully pulling the trans into 6th, so that it's riding on the edge of full engagement.
Agree that it sounds like a cable issue.
I've been "living with it" for the past few weeks, but I'm about to get into the shifter mechanism inside the car and see if I can make any mi or adjustments in there. I'll install some washers to remove the slop that has built up over the years in the SSK.
Wish me luck.
Tightened up most slack in the shifter mechanism in the car. All good there. Temporarily adjusted cable to make sure that pulling into 6th was fully seating gear. No change, so I set the cable back in its original position.
Spoke with Stanley at Gbox in Boulder, CO. First thing he said is "it is not a cable issue". Indicated that it might be as much as $2k for him to do 1 of the 4 things he thinks could be the cause. Said that the best way to ship it to him is in a 140qt igloo cooler via FedEx.
I checked and see that slow shipping will be $70 each way (more or less) from Charlotte NC.
Before I go that route, does anybody have a transmission shop that they would recommend within 5 or 6 hours of Charlotte? I have a conversion van and can easily remove the transmission and carry it to them.
Thanks for any feedback/help.
JT
This isn't accurate. The dog ring on 2nd gear can be replaced, if its teeth are worn to the point making that necessary. Access to 2nd gear is pretty easy: it's close to the top of the gear stack when you've removed the gear housing.
I'm in Massachusetts, so probably not going to fit your six-hour window unless you're a bit of a lead foot. It's unusual for 6th gear to take a hit inside these gearboxes, because the 5th to 6th shift generally doesn't get rushed, and the torque being managed is the lowest of any upshift. Unusual but not impossible. If you've checked the external linkage and everything is copacetic, yeah, going to have to take a look inside. Popping out of gear generally means there's an issue with the synchronizer rings (these are three-piece synchro rings), the 6th gear dog teeth, the matching teeth on the shift sleeve, the detents in the shift sleeve, or the shift fork that controls the shift sleeve position.
