I just had a lot of issues with my tranny. My tranny mount was cracked in two, which obvisously wasn't good. But the main issue was code P1811. Which is the Pressure Control Solenoid. Check the common problems sticky and see if maybe it corresponds to what your experiencing. My problem was abrupt upshifts at low speed and you could definitly feel it.

You know my tranny started doing that before I did the swap. There was a lose motor mount on the rear of the tranny near the down pipe. You may check there, but after I put the bolt back in it didn't fix the problem. All I can tell you is that when I put in the new tranny it didn't do it any more, and shouldn't. The engine does move a lot in the bay. It isn't as fixed as a grand prix and doesn't have any solid mounts in the Bonnie. They are all a bit moveable.

You guys have GOT to replace the front hydraulic oil filled mount with a solid puck

Hans also make sure to check the drive shaft joints.

This is obviously the front transmission mount. I've been through a dozen of them, I know what it feels like.

front transmission mount WTF????I thought it was the REAR transmission mount in the FRONT of the car. the one that I'm going to get some practice pucks for.....


In changing the valve cover gaskets tonight I broke the FPR to BCS vacuum line DOH!!! stupid brittle plastic lines. I also found a lot more little problems I'm going to work on tomorrow. the Number 5 plug wire is completely trashed, it barely stays on the coil. its wiggling around and stuff. Its been arcing for so long I think the coil might be trash.....That might explain the random misfire I get at times.

Right now the engine is moving 5-6" at the moment. almost hitting the firewall.

Looks like a trip to home depot is in order to fix the car lol.

The front transmission mount is the one that is replaced with a hockey puck.

The mounts are named relative to the car, not the transmission. You've probably lost hydraulic pressure in the mount, The engine will sit there with just the three mounts but it will move under power. BTW, the more you goose it right now, The sooner you need the rear-pass dogbone.

Off the wall but...

About 3 years ago my 98 LeSabre (with 4T65E) had the exact same symptoms you describe. It didn't throw any codes, so I took it to the shop.

Turned out to be a vacuum leak in the brake booster (it had cracked at a seam). Got the brake booster replaced and tranny was perfect again.

To this day I don't know how a vacuum leak can affect shifting on a 4T65E...I don't mean to "hijack" this thread, but can anyone enlighten me on that?

I think it was the motor mount..I just completed installation of the new motor mount and am about to go drive it..the motor was moving a long ways..now it moves an inch or two.



...the mount was BROKEN IN HALF!!!!

You bought a new mount :?:
I hope you didn't pay more than $25. for it cause that'* all it cost to make a solid mount.

Good to see it was the motor mount, I need to get mine fixed but its hard when Im away at school. Wish you guys lived closer.

tony