forgive me for writing in this forum it is read by many and I need some advice. When I am out in my truck and I am craling hills and rocks the 4 wheel drive seems to work fine and it seems to get the job done. Today I got into a stcky situation in the mudd and I had to put it in 4 low and nothing happened. THe front wheels wont spin but I can feel it ingage. I jsut replaced the vacum so I thought that would make it work but now it seems to be doing it again has this happened to anyone and is there any advice out there that can help me?

 

Had a problem similar to this on my work truck ('97 4x4 V6), lights came on, felt like the Xfer case was engaging, but the front wheels didnt spin...had to call up my boss to get pulled out.

In any case, one of the plastic vacuum lines that runs up from the little shift motor (black canister lookin deal) on the front differential had come loose...they run up along the fender liner on the passenger side. Start at the bottom at the shift motor, follow the lines up, and make sure they dont have any cracks, are connected at all ends, etc.

Although, in my instance, 4 wheel drive did not work in HI or LOW, so Im not sure if this is actually your problem...but its something to look at.

Also, when you say you replaced the vacuum, what exactly do you mean?

 

Jack up the front wheels and with the key on engage 4lo. Does the front drive shaft turn? If it does then there is a problem with the t-case. If it doesn't then most likely the problem is with the front axle engagement.

JMC

 

...wouldnt he want to jack up all 4 wheels? Since it is going into 4wd and all

 

You need to jack up just the front wheels. In 4x4 with the rear wheels on the ground they will not turn. Because the t-case locks both drive shafts together the front shaft should not turn with the rear wheels blocked on the ground. Up in the air the rear wheels are not blocked and it could lead to a misdiagnosis.

JMC

 

I don't think JMC was clear... Jack the front end up, get the wheels off the ground, and manually try and turn the front driveshaft by hand. If you can turn it when it's locked in 4low, the problem lies in the t-case. If you cannot turn it, the t-case is locked and you'll want to focus on the front axle's center-axle disconnect.