byrdman454

Got a call from my nephew today and he is having issues with his 928 I built for him. The car will not shift out of second gear. This happens when the gear selector is in drive and also when the gear selector is in "3". The fluid and filter was changed about 3 years ago with Mobil1 full synthetic ATF. The car has about 75000 miles on it and the mileage since the fluid change has only been about 10000. I was hoping someone had some ideas to have him check before I make a trip there or have it towed to my house. The car does not leak a drop of oil, so the ATF level should be still topped off. I was thinking possibly a shifter cable problem, valve body issues, or internal trans clutch went out. Is there an additive out there to try before complete rebuild? Does anyone have a brand/type for this?

MainePorsche

SeaFoam's Trans Tune - sludge/varnish remover for valve body component sticking

ammonman

Just because you aren't seeing any fluid on the floor doesn't necessarily mean it isn't leaking fluid. Have him check the fluid level first before anything else.

Mike

MainePorsche

+1

byrdman454

Finally got to check out my nephew's car. The oil level was at the min mark, so I filled it up and drove it. No change. I went ahead and sucked out at bit of fluid and added the SeaFoam TransTune. No change. I did verify the shifter if working properly and the cable is moving the lever at the transmission just like it is supposed to. Does anyone have any other suggestions before I start making plans for removal and rebuild?

ammonman

The Seafoam might need a bit of time to loosen up any varnish in the valve body and centrifugal governor. The other possibility is that the centrifugal governor is stuck. This can be removed and cleaned with the trans still in the car. If cleaning the governor doesn't do the trick and the Seafoam doesn't help the valve body you can try removing the valve body and disassembling it for a good cleaning. This will require a lot of care to get everything SPOTLESSLY CLEAN and all the bits back in their correct place. The WSM will be a big help for cleaning the governor but it's pretty vague on the valve body. Be sure to take lots of pics, make drawings, and have lots of cups/bins/boxes to keep all the internal parts organized and oriented correctly so you know how it goes back together. Dr. Brown says addressing the valve body is the most time consuming part of doing a proper rebuild.

Mike

76FJ55

How are the 1-2 and 2-1 shifts? If they are high cold be that the full throttle switch below the throttle pedal is stuck closed.

Bonton

Can you post a link to the WSM portion of the govenor? I need to access this for cleaning too.

M. Requin

I'll add one comment, although you probably know this already, follow the WSM recommendations on checking the fluid level in the tranny TO THE LETTER! It was very easy for me to make assumptions when I first got my 928 about "what it really meant", and I screwed it (checking the fluid level) up several times before I got the procedure right. Like adjusting the clutch on the bike in my avatar (no, not 4 springs to adjust, 21!)...