Bad meatl scraping sound when in 4X4

DIRTYDAN

MEMBER
1989 GMC SIERRA
V8
4WD
AUTOMATIC

Hi, I have a 1989 gmc sierra, its lifted 6 inches, I have allmost everything redone on my truck but it never seems to end, we had a snow storm in toronto today and I put my truck in 4x4, it shifted in gear fine, the the second I started to drive a terrible scraping sound came from the left side of my truck, it only happens in 4x4, it only happens when I give it throttle, my transfer case was recently serveices and filled, when I take my foot off the gas it goes away, and it drives perfect when im in 2wd. All my u joints are only 6 months old and my truck does not shake when I take off so I do not beleive its my u joints,
is it my transfer case? Or my front diff? Or somthing else? Whats a rough estimation of a rebuild of my transfer case.

1 Reply

HMAC300

MECHANIC
48,601 POSTS

Well if it doesit only in 4wd then'i'd suspect one of the front axles or the axle itself. Check for broken bootsup front as it would leak grease all over and the joint will fail. Also look for rubbing marks on the driveshaft as something may be rubing it as well. If your t case is full then it may be a metal shieldrubbing on the frontshaft. If you raise the vehicles like that tand don't get teh frontend fixed to takecare of the raise then you can run into problems from it. There arekits on themarketto do this That could well be your problem depending on whether it has been a long time since it's done and something else has worn causing therubbing sound.