I had a bearing go bad in the transaxle (output shaft bearing). I decided to pull the complete drivetrain, repair the transaxle and do some maintenance on the engine/transaxle.

The transaxle was removed, disassembled and rebuilt. The transaxle got new bearings, new 2nd gear, new 1st/2nd gear guide sleeve and CMS shift arrester. I'm also adding an upgraded clutch (Sachs 764 pressure plate and GT2 disk).

There is more information on the transaxle tear down in this thread.

https://www.6speedonline.com/forums/...ear-specs.html

The engine compartment received a new coolant over-flow reservoir and fuel filter.

The engine had all the coolant pipes pinned and the oil-cooler o-rings (which were leaking) replaced. I also replaced several other seals, hoses and o-rings, while I was at it. The new spark plugs were the last piece before bolting on the transaxle and putting it all back in the car.

I actual drove the car 30 miles yesterday, with no issues. Fingers crossed.

I was really amazed at how the clutch pedal with the Sachs 764 pressure plate still feels stock. Barely any increase in pedal effort. I will say the GT2 disk (which is a solid disk) does tend to be a little less progressive (though not an issue). Definitely NOT an on/off switch.

This was definitely a major undertaking with the transaxle tear down. Tons of time in cleaning all the parts. There is definitely peace of mind knowing I have the updated bearings (at least a new part number), CMS shift arrester, stronger clutch, new coolant overflow tank and pinned coolant pipes.

Below are some pictures that tell the story. Enjoy.




















If you look closely at this picture, you can see some of the pinned coolant pipes.




After the return from the maiden voyage, happy all 7 gears work and there are no puddles under the car.




Thanks for sharing the journey,
Steve

 

Nice project...she must feel like new again!!

764 pressure plate and GT2 disc are on my upgrade list when it comes time. I am looking for minimal pedal effort increase so that's nice to hear that it isn't much more effort.

 

Nice job, did you do work in your garage?

 

I like home garage wrenching projects. What did you use to hold the drivetrain or bring it down? Did you do all the transaxle work yourself? I'll probably start doing mine sometime this January or February. I see you have a red E46 M. My brother and I just finish putting in an engine on his red E46 M. Engine went after 160k miles.

 

Thanks

I did everything except the tranaxle rebuild in my garage. I took the tranaxle to a friends house, because he borrowed the special tools needed from a retired Porsche master tech that he knows (and he has a bigger work bench).

 

I used a motorcycle jack and a wood form I built. The wood form spread the load across the engine block, cylinder heads and transaxle.

My friend and I did all the transaxle work, but we had tools and advice from a retired Porsche master tech he knows.

My M3 had 201,000 miles on it and is still going strong. It did a weekend on the road course in October with over 195,000 miles on the odometer.

Later, Steve

 

congrats steve! always feel the difference instantly with a refreshed box!

very curious to hear your take on the cms arrester? it seems a VERY solid piece and in another league from the gbox detent etc.

wondering about 1/2 shift "feel" now since obviously you've done this as some form of "preventative" now. also..if i may.. why? cheap "insurance"??. again, it';s a tough looking little part! kinda like brass knuckles lol, could see using it myself if needed/wanted.

again, nice to see you back up and running.

 

Nice work and thanks for the pictures!!!

 

Let me give you a little background and then I will share my completely uneducated theory on the shift arrester. This is what made me decide to replace 2nd gear and the 1st/2nd guide sleeve.

When I purchased the car, there was no issue with 2nd gear pop out (thanks to this forum, I knew to check for the issue). I had launched the car a couple of time with the old/hard Pirelli tires and even with the stock clutch and 515 wtq, the clutch would hold and the tires would spin. Basically no problem. After installing a fresh set of PSS's, I tried to launch the car and after what felt like tire slip, I missed 2nd, grinding the gear. I very quickly discovered that the clutch was slipping instead of the tires spinning. After this incident, 2nd gear pop out began.

Within 3 months of having consistent second gear pop out issues, an interesting thing happened. I was slowing with the car in second gear (typical pop out scenario) with my hand on the shift lever. Suddenly the gear lever popped out of 2nd and startled me. Without thinking, I yanked (aggressively) the gear lever back toward second gear. When doing this, there was a terrible grinding sound (much worse than when I did the damage). Surprisingly, I never had another issue with 2nd gear pop out.

This does not mean for everyone with 2nd gear pop out issues to go out and grind the heck out of 2nd gear, this was just the story behind why I felt it was necessary to replace 2nd and the 1st/2nd guide sleeve.

With that said, here is my theory on the 2nd gear pop out issue and the advantage of CMS shift arrester.

Let me start by giving my basic understanding of what's causing 2nd gear pop out. It's not an issue with the larger teeth on the gears themselves. Hopefully the picture below will help illustrate the parts I'm going to reference.

Basically there are teeth on the inside of the shift collar that mesh with the "small" teeth on 2nd gear and the teeth on the guide sleeve. The guide sleeve is fixed on the output shaft and the shift collar rides on the guide sleeve between the free-wheeling (loose gear) 1st and 2nd gears. When you select 2nd gear, the shift collar slides towards the loose gear 2nd gear and engages the small teeth on the gear. At this point the shift collar has engaged the loose gear 2nd gear and the fixed guide sleeve, causing the guide sleeve to drive the output shaft.

If you miss a shift, or have a bad shift, the teeth in the shift collar grind against the small teeth on the loose gear 2nd gear. At this point, the teeth of the loose gear 2nd gear and the teeth of the shift collar are damaged and no longer engage at full strength. This causes the shift collar to slip off the loose gear 2nd gear small teeth, disengaging 2nd gear. Basically, this is what we call 2nd gear pop out.

What you want, is for the shift collar to move as far as possible onto the small teeth on the loose gear 2nd gear (and stay completely engaged), to reduce the reliance on the leading edge of the small teeth (which are what wear or get damaged). This way as the teeth wear, you will not immediately get 2nd gear pop out.

The shift arrester (which replaces an almost identical factory part) has a different profile, which will change the travel of the shift rod slightly causing the shift fork and collar to more fully engage 2nd gear (actually all gears). I believe Porsche used different shim specification to adjust for this issue (partly because this would require a redesigned part on an out of date model). I think the CMS shift arrester is how this fix should have been done.

Later, Steve

 

absolutely brilliant! the story as well as your take as to the "how's and why's". i have no doubt that the shim tolerances were a very "late to the game" discovery and realization on the part of porsche and obviously one they were loathe to admit.. and i was basicially told as much myself. the only reason i know half of what i do know is i had direct dealing(s) with pcna directly as well as with the svc manager at a huge la area dealership in a LOT of initial back and forth on a warrantied 996t.. we got so far in on "this", that all initial pretense and subterfuge they initially attempted on and with me fell away quickly. it was also no coincidence that i had previous history directly with pcna on a ANOTHER 911 and had emerged successfully, not an always easy "feat", so i was prepared when i began. also, as i've said; i'm in their "books" i would venture lol.

i'm going to read your story again, but am fascinated and in AWE the the 2nd gear pop STOPPED!? after a rough shift, once damage had been done?! that is , but only because this has turned out so favorably.

i also ( knowing a little bit, but not like a "tech" "should"!, and as you can see from any of my musings on this topic? ) I am, and have been, a huge proponent of the CMA "arrester". you have terrifically articulated as to "why". great post and results. thx!

 

also whatever those parts in your pics are? its the dogring/synchro that get rounded in very simple terms. ( as you OF COURSE already know ) but once rounded? that dogring will never again, regain its bite. sorry, just had to say that. i'm to be held accountable for my puns, some day.

 

When I say 2nd gear pop out stopped, I mean I drove the car for a couple of years afterwards and the car never popped out of 2nd. Almost made me consider leaving the "damaged" 2nd gear and 1st/2nd guide sleeve in the car.

Thanks for your kind comments.
Steve

 

Congrats on getting it back together and for sharing insight and pics!

Your name looks extremely familiar.. previous MKIV Supra?

 

Yes, MKIV for approximately 15 years.

Later, Steve

 

Awesome, you've got me by a few years. I had one for 10 years starting from 1999 and the old mailing list days.

Nice to see a familiar name. Back to the thread