Another Transmission Issue

[pauloi]

I picked up a B8.5 S4 and it’s throwing a couple faults. I noticed the clutch slips when hot and then after a little while, I lose all gears. I’ve seen a lot of threads where people get one of these, but I have both P17D400 and P17D500 (Valve 3 in partial transmission 1 and 2). Previous owner claims to have changed the motherboards and solenoids but I’d like to start fresh and see if anyone has incurred the same issues (with both fault codes and clutch slippage when warm). Thank you!

[Corydms7]

I was going through a several month long process with sorting mine. I had one code (not 2), but I had P17D400 “Valve 3 in transmission 1.” Sent it off to be rebuilt and had same code upon return. Ended up buying a brand new oem mech unit. It’s been about 700/800 miles now fault free. Launches don’t feel weird now. Lol

I picked up a B8.5 S4 and it’s throwing a couple faults. I noticed the clutch slips when hot and then after a little while, I lose all gears. I’ve seen a lot of threads where people get one of these, but I have both P17D400 and P17D500 (Valve 3 in partial transmission 1 and 2). Previous owner claims to have changed the motherboards and solenoids but I’d like to start fresh and see if anyone has incurred the same issues (with both fault codes and clutch slippage when warm). Thank you!

[pauloi]

Cory, thank you!! It was actually my TCU pressure sensors being corroded but a whole new mech unit took care of the issue. Thanks!

[Corydms7]

Yeah I hear of people rebuilding or doing all these things to fix their mech unit. It’s better to just buy a whole brand new one. It’s the peace of mind to not have to worry about another wiring harness, seal, solenoid, valve failing.

Cory, thank you!! It was actually my TCU pressure sensors being corroded but a whole new mech unit took care of the issue. Thanks!