Had the synchros replaced in my gearbox, 1st, 2nd and 5th and 6th. When in 5th the gear feels really loose like it wants to pop out, that's the only way I can describe it but in 6th it grinds and pops out. I was told there is a 500 mi break-in period but wasn't expecting 5th and 6th to feel and respond the way they are. The guy who rebuilt it said the synchros are really tight and will loosen up when he first gave the trans back. A friend said 6th grinding is likely the tight synchro stuck rotating with the gear and just needs to be driven/shifted into to break it in and loosen it up. Before I shred 6th gear up I figured I'd ask and get other opinions anyone know if this is the case with 6th and it's ok to shift into it?

(Why 5th and 6th were replaced in the first place is another story, I don't feel it was necessary and the guy was just milking me for more $)

 

If it were mine it would come back out and come apart again. There is no break in period that will fix a grinding and pop out issue. Sounds like something didn’t get put back together properly. Good luck, I hope you get it worked out without too much hassle.

 

Thanks, I’ve finally accepted the fact that the guy f’d my gearbox up worse than when he got it. He was recommend by a friend and he claimed to have rebuilt thousands of transmissions and is ZF certified and worked on Porsche transmissions before.

I should have taken my transmisson and ran when he fumbled through describing some features of mine. Tough lesson to learn but I suppose it could have been worse

 

nothing about your story reads well. there is no "break in" period for the 1-2 geared triple cone synchro's in the m96g50 box. you mention "grinding" and popping out. the original and now legendary issue of "popout" in 2nd gear was a result of a rounded dogring of the 2nd gear synchro based upon less than optimal original factory shim tolerances that were later ammended by porsche factory which minutely altered the gear stack placement positioning with different specs. this is why the issue never manifested beyond MY's '01 and '02.

you shouldn't be grinding in any gear. let alone 6th. you need to re-open the box? or double clutch and rev match and live with the error. GL with it.

 

Guy confirmed something is likely up with the 5th/6th shift fork so out the engine and trans come again. Boy I am getting good at this!

The guy started to say that someone else had been in the transmission, never said that before, and started to say that that person must have weakened the bolt or threads. The fork didn't work from day 1 with the rebuilt trans and I feel he didn't put it back properly or over torqued or just plain broke the fork and didn't realize it.

When I went to pick the transmission up I noticed right away the oil cooler line was disconnected still. I pointed it out and he asked if I did that.

I've spoken to CMS and am sending to them. I want them to check this guy's work and then replace the fork he broke. Only cost me $415 for the new fork (no OEM avail), thanks transmission hack! $4300 mostly wasted at this point and going to have to shell out even more

 

i've been inside ( standing there i should say ) the box was R&R'd twice, and the only thing i remember ever being an issue when buttoning it all up is the alignment of the shift fork. we once had to fiddle with it for well over an hour to get it to align properly.

i don't know if it can even be installed incorrectly. but it's a common source of frustration when reassembling. this i know for certain.

i once spoke with roger at cms and he's a real knowledgeable pro so you're in good hands. i was lucky not to need to send him my g'box but would have if i hadn't been able to repair it locally. i spent $4k last time removal repair and re-install on a wavetrac install and replacing bearings. big difference from when we replaced my clutch on a rented lift! but then that's why the clutch fork took so long to re-install i guess. everything is a "trade off" when DIY'g.

as for me, i'm swapping gear oil next week. i'm at about 25k miles since my last delvac flush and am taking NO chances. first sign of notchiness on a cold AM and for me - it's "time". GL with the repair!

 

Thanks for the info 02996ttx50. I watched yesterday as well and wasn't clear what the cause was, it seemed like the fork may not have been aligned properly because it would really struggle to go into gear when he tried to do it, seemed to get stuck. He pulled R off and then 5th/6th and the clutch fork and the bolt came out stripped so he claimed it must have been the issue but I don't know about that. He claims to not have over torqued and his co-mechanic, the shop owner, said initially that he watched the guy look up torque specs when first putting it all back together yet yesterday, no torque wrench was used and he cranked the crap out of the both fork bolts when putting back in and saying he thinks that's 15 lbs of torque ... unreal for someone who has 30+ years and rebuilt thousands of transmissions and just dealt with a stripped bolt out of an aluminum fork.

The most disappointing part was the lack of taking any responsibility for this issue but that's here nor there and not helpful to this post. Putting all back together today so hopefully all is well.

 

i completely empathize. indie tech/shops can be a double edged sword. i've had the unfortunate experience of dealing with a huge LA based dealership with a factory trained head tech who rebuilt my g50 box to cure 2nd gear pop on my first 996tt and he was unaware of the revised shim specs that zuffenhausen finally made dealerships aware of, as there were too many "2nd gear popout" occurrences for them to deny it was manufacturer error. ( they tried to deny me a warranty claim and it required a minor skirmish with PCNA on my part as the dealer quoted my 8K$+ for repair on a car i had recently bought from them with CPO! thankfully i had successfully done battle with PCNA before so I knew the ins/outs of their resistance and for 8K$ was armed and prepared for battle. they actually claimed 2nd gear popout "did not exist" back in '09. this coincidentally led to my speaking to roger at CMS and as i noted he was really helpful with info.

whereas the next and my current 996tt had most all previous work done by the most reputable indie/race prep shop in LA and they knew exactly what to do when adding the wavetrac and replacing bearings etc. and did it correctly, inexpensively and fast. i think the "turn time" was a week on all the work.

truly double edged sword experiences. plus dealers will only go strictly "by the book" and the "book" made opening the box up a second time necessary on the warrantied car! the only thing about the "book" i still appreciate is torque specs and you know why!

good luck man. it's frustrating but once done right? you're good for some time. one last thing. do NOT adhere to the factory interval on gear oil changes. 90k miles!? they're nuts.

 

Cervelli Technical Service or Bill Radar are some of the most reputable shops for doing trans rebuild. To really go through the box expect to spend some bucks. I hope you get your problem worked out!

 

Forgot to mention why I decided to take a chance with the local guy again - labor was free and I could watch and CMS was 4-6 weeks out and I am in the process of buying another home and will lose my garage/lift space on my current in 2 weeks so couldn't really leave it up in the air for that long. If an issue arises again, and I expect it will, I'll figure out how to get to to CMS or check out Cervelli.

 

I appear to now have a 2nd gear pop out issue, guy says it should go away after break in, but based on what was mentioned earlier that doesn’t seem to be a true statement by the trans guy. I know he reshimmed 2nd after he put the new shift sleeve in.

I never had the issue prior and GT2s are not know to have it period. Moving my right shift cable up 2 notches helped and I thought I had it solved but then it popped out again. Happens when I slow down while in 2nd. Not every time.

Did the guy not use the latest shim specs or is this a shift cable issue still or something else?

 

terrible to hear. 2nd gear pop primarly occurs on decel particularly downhills when the load is shifted. i actually had it pop out on a slight uphill climb before having is repaired. but this info doesn't help you.

you're correct that it is not going to improve which gets into the "band-aid" fixes ( some work ) like the detent's and the shift arresters ( cms makes?/sells ) and the infamous ball bearing fix that user name tim914nyc(??) here had devised or knows about. the latter being the one with the most anecdotal reports of success absent opening up the gearbox as that can be done on a lift - if memory serves.

so if you had all new 1/2 synchro's and associated parts just refreshed and now have this issue ( as once happened to me ) then i would suspect that the guy used the OLD factory specs re shims. not the revised.

this has happened countless times as porsche only finally sent bulletins to their dealers after a few years of denial that the issue was even "real". these specs would not have been sent to indies but truly experienced indies ( my folks knew of and - roger@cms/copans/bill radar and the like would be well versed also in the issue and the ammended shim tolerance specs and they have been for years.

shift linkage issues are mostly difficulty with engagement/notchiness etc. not actual "popout". but that's anecdotal as i've never had shift cable issues myself.

you need to get the box re-opened sorry to say but first have a detailed conversation armed with the updated shim tolerance spec info. this sucks and i've been through this same exact scenario. albeit 12 years ago. still fresh in my memory as the worst case situation.

 

where are you located? another gearbox king is Brian Copans in Ohio

 

Brian is one of the best.... period

 

I have the gearbox at one of the shops recommended in this thread. On the topic of 2nd gear popout I am basically being told that there is no guarantee it won’t still happen after the shop works on my issue and that it just seems to happen with some gearboxes and is hard to prevent. He said he may recommend I use the GBox dent solution.

The person seems very knowledgeable and has been great to deal with and was recommended here but the above is not the answer I was looking for with my new popout issue that wasn’t there before.

Is the answer I was given really a realistic answer and one I should accept? Because I don’t think it is and I should expect that my 2nd gear popout be fixed…

@02996ttx50 do you by chance have the correct shim specs I can give him?

I can’t seem to catch a break with this gearbox