I have an 88 pickup that is still ifs and one day I was parked in a ditch at work and when i left, I put it in 4 low to climb out of the ditch and i heard a big clunk in the front end. I thought it was one of the cv shafts, but after replacing them, it still does it. It snowed quite a bit here and i discovered that my four wheel drive isn't working. I think it might be something in the diff. any ideas?

 

Well if you hearing clunk's when in 4 low then it might be you'r diff for sure.. but i could be wrong though. I would take it a part might be something crack in side..

 

Its not just in 4 low, its whenever the hubs are locked and the t case is in 4wd. Super frustrating.

 

sounds like the t bars they all do it

 

I would definitely jack up the front of the truck and inspect your hubs, CV's, and well being of your front diff.
Torsion bars don't "clunk" in 4wd..

 

I know that it isn't the t bars, because they have always been cranked since I have had the truck. Also, it only happens in four wheel drive.

 

does it feel like a dragging tire/clunkin when in 4wd. my 3.0 xfer case chain had stretched and was causing it. just my 2 cents with a problem i had after replacing 2 CV's and taking apart the diff

 

88 doesn't have a chain driven Tcase, it's a gear drive so that wouldnt be the issue.
Again, have you jacked up the front of the truck and started wiggling parts?

 

So I still had all the IFS stuff i cut off of my other truck, and i swapped out the diff and both cv shafts and the noise is gone and four wheel drive works again. Thanks for all the help. Now i can enjoy the snow!