Rear differential locked after clutch replaced?

[Ppd7207]

I just finished replacing the clutch in my 2003 rubicon. As such the rear drive shaft was out and the front was disconnected from the transfer case and tied to the frame rail. I also replaced the transfer case oil, with ATF-4. Took it for a test drive and all seemed great. During the test drive, I shifted into 4 HI. It drove straight fine, but when I tried to turn the rear differential felt like it was locked up. Any idea what could have happened?

 

[Jerry Bransford]

If you were in 4Hi on pavement you will have trouble steering since the front and rear axles were locked together by being in 4x4. Don't shift into 4Hi or 4Lo when you're on the street.

 

[Ppd7207]

If you were in 4Hi on pavement you will have trouble steering since the front and rear axles were locked together by being in 4x4. Don't shift into 4Hi or 4Lo when you're on the street.

I thought the differentials were only locked when I activated the electric lockers?

 

[jjvw]

I thought the differentials were only locked when I activated the electric lockers?

They are. But our 4wd system can create some binding between the front and rear axles because they are now mechanically tied together. This will cause some hopping and skipping while turning on high traction surfaces like pavement (or Moab).

If the rear diff was locked, then the Jeep would really want to push hard in a straight line, despite your efforts to turn. It's dramatically different than what 4wd does.

Assuming they are stock, your Rubicon lockers are pneumatic, btw.

 

[Jerry Bransford]

True the axles themselves are not locked. But another way of putting what jivw said is that the front tires need to turn faster than the rear tires do during a turn. The front tires are locked to the rear tires whenever you're in 4x4 (4Hi or 4Lo) via the transfer case. The Wrangler's "part-time" transfer case does not allow for the F/R axle driveshafts to rotate at different rpms so the front and rear axles are locked together. The L/R tires are not locked together at the axles when the axles are not locked but that's not the issue causing your jerky steering. Shift back to 2wd and after driving a short distance with a L/R turn or two, the transfer case will unlock and your steering will feel normal again.

Only "full-time" 4x4 systems like are available on Cherokees and Grand Cherokees don't cause steering issues on pavement because their full-time transfer cases (they have a differential between the front and rear inside) allow the front & rear axles to rotate independently of each other.

 

[Ppd7207]

Thanks for the quick replies. I’m going to congratulate myself on my first clutch job and call it a success.