I have been test driving my jeep for other issues and I noticed the front diff was leaking and the front drive shaft is always spining. I checked to see if the fulltime and parttime lights work and they do when I put it into 4x4. When its in 2wd no lights are on but the shaft still spins. Thanks in advance.

 

If it didn't spin I'd be worried. But, yeah your front shaft will spin while your driving in 2wd.

 

The system is controlled by a vacuum motor and shift fork, actuated when the transfer case lever is shifted into one of the 4wd ranges. When disengaged, the differential is allowed to freewheel instead of turning the ring gear, pinion and front driveshaft, thereby saving unnecessary wear on these components during two wheel drive operation. ????

 

Oh.. You got an 89, they are vac operated, so if there are no issues with it i think everything should be normal. (On my 99) the from shaft spins, but no torque is applied. It's just free spinning. Hope I'm on the right track here.

 

I think there is an issue. That front driveshaft should NOT spin while in 2wd right?

 

Lol... Wrong... It will spin... drivers side axle shaft isnt disco now is it?? Its always spinning the shaft...

 

^This. Driver side axle shaft spins the ring, ring spins the pinion, pinion spins the shaft.

 

science!

 

Being that you have full-time and part-time, that tells me you have a NP242 transfer case. All XJs equipped with that transfer case did NOT have a vacuum disconnect front axle. Therefore, everything is normal.

 

Okay so its normal for it to spin all the time. Does having different gear ratio cause overheating?

 

Thanks.

 

What do you mean by that?

 

it is normal for it to spin all the time UNLESS you have vacum disco. if its vacum diso it wont spin in 2wd, and as far as the overheating on gear ratios your engine could possiabley be working harder on bigger gearing not too sure. wait for someone else to chime in

 

yes, no

 

Your wrong boss... Read the prior posts...