Donnie's Diesel

Well First time I Take my truck and get stuck in some sugar sand and have a chance to use my 4x4 it fails me. I went to a parking lot when i bought it and stoped put it in neutral then move the shifter to 4H it was a little tough going in but it went i drove a little made sure it was in stoped tried 4l and it had lots of pep it seemed then i decided to buy it, everything been fine cept for a surge a 1700 rpm's idle speed it drops back and forth from 1700 to 1500 rpm. The truck just has 70,000 miles on it a 98 quad 4x4 24 valve cummings auto tranny 33' tires and 6'' sup lift. Anyways when i got stuck and got the 4 wheel drive in and started getten out it popped and crackled i hated to even use it anymore to get out but i was only like in 20ft of sand it looked so pathetic i love the truck and wanta get my 4x4 worken, it works fine in 2H so people telling me its got be in transfer case , the light was comming on saying it was in gear then after about 20ft the light would go off and the shifter would move down a lilltle like it wasnt getten locked in all the way. The fools at the dealership also said my truck would go in 4wheel drive while moving and when i check it out the shifter wouldnt go into any other gear so anyone with my truck plz tell me how u lock yours in. Should i take it to a cummings place to fix the 4x4? 1 More thing the noises only came when the tires rotated it felt like springs or something there rancho 5000 the springs and nice looking too so im not sure any input would be great thanks

quantrill88

Not 100% sure I completely followed but are you stopping and then shifting the lever? If I try to do that on mine it will make a grinding type noise. Best way to do it is shift into 4Hi while moving slowly and shift into 4Lo while moving slowly but also popping the tranny into neutral. Seems like alot of 4wd systems are different (my jeep work the exact opposite of the truck )

If it is the transfer case itself (or front axle) I dont think youll have much luck with a Cummins dealer. The only thing theyll work on with our trucks is the engine.

Sorry if I misunderstood your post.
Jeff

thumper 549

your going to have to put it up on jacks (and not get killed) and check out what is going on or pay someone to do it for you.
If your 4wd lt is going on and off I suspect the vacume is not holding....check all your tubes as the sensor is right out at the front wheels- and that is where that reading comes from.
other then that joints and stuff.......like to reinterate Jacks man and plenty of jack stands ,, human pancakes are not pretty in strawbery juice

Chip

Sounds to me that your problem is in the front axle vacuum system. Your truck uses a vacuum switgh to engage your front carrier bearing and axle shaft. There may be a vacuum leak or a vacuum line disslodged from where its supposed to be, that's my 02 cents worth !!!

Chip

dieselgeek

6" lift kit?

I'm gonna bet your problem is in the transfer case shift lever. Also, the u-joints are bound to suffer at that lift height. At factory height in sand, the front axle will wheelhop (trust me) with even 305 size tires added. Most people do not realize that a lift kit and big tires simply KILL offroad performance.

Make sure your u-joints aren't binding, and you're not popping out of 4wd because of shift linkage issues. The lever length is easily adjusted from underneath the truck. If the lever is moving on you, this is likely the culprit. Did the lift kit include a lowered rear trans mount to help driveline angles a bit? (I'm guessing yes since you have no rear driveshaft problems) - if so, the distance to the T-case is even LONGER so it's more likely that the shift linkage is binding/flexing...