Changed diff fluid, now jerking!

[Windowsrookie]

Ok, just a half hour ago I sucked out the old diff fluid in the front and back of my GC (going to pop off the diff covers and change completely this summer). I put 80w90 in the front, and 85w140 in the back. Now I took it for a drive around a couple blocks and it was all good for 2 or 3 blocks. It then started jerking when taking off from stop signs. Then on the hill on the way back there was alot of jerking and the engine killed. I got it started again and brought her home, jerking at the 2 or the stops signs on the way back. What did I do?

[walter_da_jpr]

Its hard to say exactly but if I had to guess something just happened to fail at the time after you did the change. I really have no clue what it is, can you give a more specific description of whats going on, maybe some sounds, feelings, etc.

[Windowsrookie]

It doesn't seem to be making any sound. Just when leaving stop signs it will jerk and vibrate. Then going down the hill it killed the engine.

[walter_da_jpr]

Does it feel like the brakes are being applied on and off?

[Windowsrookie]

No, it's not the brakes. It feels like gears slipping.

[greasefingers]

It has nothing to do with the diff oil change but must be something else. How is the transfer case atf level ?

[Windowsrookie]

I bought ATF+4 to put in the transfer case but I don't have a big enough wrench to get the drain and fill plugs off. (Gonna borrow one from a friend).

Would lack of friction modifier in the rear diff cause jerking?

[walter_da_jpr]

Originally Posted by Windowsrookie

No, it's not the brakes. It feels like gears slipping.

I'm aware of this I'm just trying to get a sense of the feel of the jerking. Is it a harsh bang or a more gradual accel/deccel.

[Windowsrookie]

It's just a vibration feeling until I get up to speed. No harsh bang.

[Windowsrookie]

Ok, went to move it into the garage and it took a long time to start. Like 20+ seconds. What the hell is going on?

[-Joe-]

check to see if any engine codes were stored.. like a misfire or something.

Mess with anything else while you were under there?

[Windowsrookie]

Originally Posted by -Joe-

check to see if any engine codes were stored.. like a misfire or something.

Mess with anything else while you were under there?

I was going to change the engine oil, but drain screw is on so freaking tight i couldn't get it off. I hit the wrench a few times to try and get the drain screw loose but it wouldn't budge. Other wise no, all i did was put new diff fluid in.

[Windowsrookie]

Anybody? Would the lack of friction modifier cause the vibration? Would the vibration cause the engine to kill?

[-Joe-]

humor us and check the codes..

jerking when accelerating sounds engine related not driveline related unless you making sharp turns

[Windowsrookie]

I bought friction modifier from the dealership. Do I put the whole 4oz bottle in the rear diff?