It "seems" like my 4x4 is not fully disengaging. About four weeks ago I notice a slight rubbing noise as I entered my driveway . My driveway is a sharp left incline. not steep but an incline. The noise appeared inconsistantally and was very subtle. It was very hard to pin point. Well the other day I was on a road (Paved) in town that requires a stop on a steep incline. As I took a right turn the front wheels behaved as though they were lock in 4x4. It was that rubbing "I should not have my 4x4 engaged on dry pavement" feel. any thoughts
Doug


Note the truck has 47000. At 44000 I switched the front differential fluid with Amsoil 75w-90

 

Does you 4x4 work? Does the T-case shift into low? Check the vacuum source at the solenoids. The vacuum solenoids are on the firewall behind the battery. If that checks out make sure they are letting the vacuum through. The red line is the one that disengages the front differential and the blue one engages. So when the t-case is shifted into 4x4 the blue line gets vacuum. When you shift out of 4x4 the red line gets vacuum. If not check the fuses. Should be #23 in the Central Junction Box. Check the vacuum hoses that connect to the shift motor in the front differential. Make sure they do not leak. Check to see if the shift motor is actually moving the lever. You will have to remove the plastic cover to see it work. If it doesn’t move remove it and see if it moves now. If it moves I would suspect an internal problem in the front differential. Using a vacuum pump makes this much easier.


regards

Jean Marc Chartier

 

Thanks I will check all that out and get back to you
Doug

 

Well I checked some of the things such as the 4x4 actually working. It does, Low gear also works. Getting out of 4x4 is a different issue. It is very difficult to get it out of 4x4 low or hi. You really need to work the shifter from drive to netural to reverse to get results. Even with that you get the slight to very noticeable tire resistance when turning. I duplicated the problem for my mechanic. He is going to look it to it. I will let you all know the results
Doug

 

Well I was wrong the noise is no the front end it is the rear end. My limited slip is sliping Not good. I just replaced the rear with Amsoil 74w-140 4000 miles ago. Now what

 

Amsoil states that you do not require the Friction modifier but it would seem that you do. Try adding a bottle of it to the rear differential.

Regards

Jean Marc Chartier

 

I run the Amsoil also in my LS rearend and haven't had that problem. Let us know.