Front diff not releasing?

rlrarlra · December 24, 2001

I noticed that the truck seemed to be draging and I looked at the front diff. It was warm but I was not using 4x4 drive. My guestion, in 2wd, what parts of the front diff are moving and what parts are free? 1999 chevy suburban 1500.

Rich

chevy4x4trucks · December 24, 2001

Welcome to the forum. As for your question, I believe that w/ auto trac the front driveshaft just free spins all the time. If 4x4 were engaged you would be able to feel it when you drive.

95 Silverado · December 24, 2001

when in two wheel drive the axle CV shafts, axle shafts in the differential and axle and spider gears in the differential all turn when the truck moves, the sliding coupler on the right side axle disengages the axle so as to not turn the ring and pinion and front driveshaft. if driven for some distance it would be normal for the front diff. to get warm, if the front were engaged you would not be able to spin the front driveshaft by hand with all the wheels on the ground. if the front driveshaft won't spin freely either the front end is engaged or the transfer case is stuck in 4WD

rlrarlra · December 24, 2001

Thanks guys, it sounds like the Sub. is working as designed. I guess I will change the front diff. to 75w/90 synthetic (I currently have 80w/90 synthetic).

I was confused because my other vehicle's (a F350) front end is totally dead when the truck is in 2wd.

Thanks for the quick responses.

Merry Christmas.

Rich.

95 Silverado · December 25, 2001

if that F350 has the old style hubs or an automatic front hub it actually disengages at the wheel end, nothing in the differential turns, this is an advantage in some respects, but the newer set-up is more convenient and less user involved than the old stuff.

rlrarlra · December 26, 2001

It's the new style (2001) and I believe it is called ESOF (eletronic shift on the fly?). Some people have reported problems with the hubs not unlocking due to seal deterioation causing vacume lose. The front wheel setup on this ford seems to be of lousy design. The ESOF and the bearings tend to go eairly and are expensive to replace. I already had the ball joints replaced (11000 miles). Once I am out of warrantee, I will have any problems fixed with aftermarket GOOD stuff. Overall I was very supprised over the quality of the truck. I'm not making so many FORD jokes now.

Rich.