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Strange failure mode...loosing both forward and reverse gears at the same time, with no apparent debris in the oil pan.
I'd drain the differential, pull the rear cover, and see if there has been some sort of final drive failure. Heck, maybe the pinion gear sheared off or some other major final drive component failed...like a stub axle shearing off.
If not, I'd completely rebuild the valve body (replacing the piston seals, etc.), put it back in, and hope this cures things.
Worst case scenario is that you have a rebuilt valve body to install when you rebuild the transmission....
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
Unless you removed the side covers from the valve body, there is no way for a spring of that size to randomly end up on the ground....
If the primary pump has failed, the metal debris from the failure will be throughout the transmission....there's no filter or strainer after the primary pump.
A complete rebuild will be required.
Fortunately, the primary pump failing is an extremely rare event....extremely rare.
We will put the spring in the valve body this afternoon, and we will check all pistons.
If it doesn’t solve our problem, I think we will have to check the primary pump. Do you agree ?
What is the best way to remove the primary pump ? Where to buy a new one at the best price ?
You located the position where the spring came from? Unless one of the covers came off, there is IMHO no way that this spring is from the valve body (like Greg said).
01-19-2021, 01:25 PM
