96 850 Stalling In Gear

hillm5714 · Post by **hillm5714** » 29 Dec 2010, 20:49

I bought an 96 850 recently that runs great as long as it is in Park or Neutral. As soon as you put it in any gear, forward or reverse, it stalls. Exactly like popping the clutch on a manual transmission. After reading a some things on here I thought for sure it was the SL solenoid (torque converter lockup). Well, I replaced that and it still has the same issue. It shifts great when the wheels are off the ground. I even had a friend push me up to speed with it in neutral and then put it in drive and it run and shifts through the gears just fine......until you try to stop. It's exactly like trying to stop a manual transmission car without pushing the clutch in. It just snubs out. What should I do now? Any help would be greatly appreciated.

Post by **phils94850** » 30 Dec 2010, 01:57

do you have a "check engine light" on ? any codes ? Check and make sure you dont have any vacuum leaks. A car stalling usually isnt due to trans problems. Id say its a vac leak somewhere or a sensor problem or a dirty MAF.

hillm5714 · Post by **hillm5714** » 01 Jan 2011, 17:42

I had a friend scan it and he said he can't communicate with it. Something about a Communication Error. He has a $3000.00 dollar OTC scanner. Is there something wrong with the plug or the wiring? What should I do now?

hillm5714 · Post by **hillm5714** » 02 Jan 2011, 19:00

I forgot to mention that this is not a vacuum leak. This is definitely a mechanical stop of the engine. It is immediate and very abrupt. The car does not stall in gear with the front wheels off the ground or if I get a push and I am moving before I put it in Drive. As I come to a stop though it shudders and eventually dies. Thanks.

Post by **jimmy57** » 02 Jan 2011, 22:05

The TCC lock is not done directly by the solenoid. The solenoid applies oil pressure to the TCC lock valve which moves over and does a TC fluid flow reversal to move plate to apply TC clutch.
I have been able to unstick these a few times by applying brakes and then while applying brakes also apply throttle. Brake application cuts off the TCC solenoid. Of course you will have to get car rolling and then start it and drop in gear to ever be able to try this.
OH OH! , have you tried removing the TCM to see if the problem is still there? If TCM is removed the solenoid can't have a ground out of TCM to operate solenoid. If TCM is removed and it still stalls then remove fuse for TCM and transmission and repeat testing. This can be done with car on stands. IF the fuse removal does it then you have a wiring fault. TCM removal does it means TCM fault. DOes it with TCM and fuse out means stuck TCC valve or stuck TC clutch. Then you do the rolling start brake/throttle thing. The good news is the TCC valve is in valve body and not in trans oil pump like on many AT's.

hillm5714 · Post by **hillm5714** » 03 Jan 2011, 18:36

Thanks jimmy57!! That gives me a place to start looking anyway. So I should pull the TCM right out of it's connector start it up and see it works? If not....put the TCm back in and pull the fuse and try it again? Or should I pull the fuse with the TCM out? Thanks for your help.

Post by **jimmy57** » 03 Jan 2011, 21:23

If you pull the TCM fuse then whether the TCM is in or will not matter as it will be powered down and dead.
Good luck and keep us posted. Maybe it won't end up as a trans R&R to repair it.
Stuck TCC has not been something I have seen on these cars but it happens and wiring faults can cause it.
Least likely cause would be the torque converter itself. There really isn't anything to fail to keep it in the locked position.

Post by **jimmy57** » 03 Jan 2011, 21:24

OH, the trans will take off in 4th with TCM or fuse out. You can get third by moving gear lever down to 1.

Even though the trans will not be shifting it is a valid test to see if the TCC is still on full time and causing a stall.

hillm5714 · Post by **hillm5714** » 05 Jan 2011, 16:48

It worked!!!!! I flush the trans fluid with about twelve quarts. It still wasn't working. I put a can of SeaFoam TransTune in it. Then ran it on jack stands and slammed on the brakes a couple times and it freed up. Then I flushed the TranTune out and I'm good to go. Thanks for all you help jimmy57!!!

Denton · Post by **Denton** » 25 Mar 2016, 19:18

My '96 850R is doing the same thing. Once the transmission warms up it's OK.

Think a transmission flush would help?