Front End issue

[urbanburban91]

First some truck info: Slightly modified 91 suburban, 1500, 350 tbi, 700r4 tranny, stock transfer case, stock 10 bolts. Lifted 4" and running 35's and running Warn Premium manual hubs. Bought it new in 91, 218,000 miles currently. Still running 3.73’s front and rear.

This issue just came up after driving around on snow and ice covered roads. I do not use this truck for anything but casual off road trails or beach fishing trips.

Started to notice a lot of noise in the front end of the truck in 4wd at 35-40 mph on various types of surfaces (wet/dry road, snow and ice) Noticed every time the truck would go front road to snow patches at 25-30 mph the truck would want to pull right every time for a split second. The noise will continue if the hubs are locked in 2wd. With the hubs free, it will not happen in 2wd or 4wd.

Put the truck on 4 jack stands and ran in 4wd, no problems found. Could not duplicate with no load. Drove it again and still had the problem, jacked it up with it still in 4wd and noticed the right front tire spun backwards like it had a lot of torque applied to it. It seems like something is in a bind. It’s not a daily driver, I do not use 4wd much in this truck, this sound does not seem normal. ANY IDEAS?

 

[imiceman44]

First some truck info: Slightly modified 91 suburban, 1500, 350 tbi, 700r4 tranny, stock transfer case, stock 10 bolts. Lifted 4" and running 35's and running Warn Premium manual hubs. Bought it new in 91, 218,000 miles currently. Still running 3.73’s front and rear.

This issue just came up after driving around on snow and ice covered roads. I do not use this truck for anything but casual off road trails or beach fishing trips.

Started to notice a lot of noise in the front end of the truck in 4wd at 35-40 mph on various types of surfaces (wet/dry road, snow and ice) Noticed every time the truck would go front road to snow patches at 25-30 mph the truck would want to pull right every time for a split second. The noise will continue if the hubs are locked in 2wd. With the hubs free, it will not happen in 2wd or 4wd.

Put the truck on 4 jack stands and ran in 4wd, no problems found. Could not duplicate with no load. Drove it again and still had the problem, jacked it up with it still in 4wd and noticed the right front tire spun backwards like it had a lot of torque applied to it. It seems like something is in a bind. It’s not a daily driver, I do not use 4wd much in this truck, this sound does not seem normal. ANY IDEAS?

Well I will take a stab at it.
You seem to have some slack in there which is not uncommon on a 200+ thousand miles truck.
I want to say it probably is either ball joints or spring centering pin.
First look to see if the left side spring has a clean surface in front of or behind the spring plate, like something was going back and forth and scraping the dirt off.
That would be a sheared centering pin.
If not, then lift it up and try to wiggle the tire in every direction you can, it shouldn't move but if it does then you found your problem.
Now if it doesn't move that way get a pry bar and try to lift the spindle off the axle "C".
Try these and get back to us and we have more...

 

[urbanburban91]

Thanks, I checked the ball joints. Ball Joints are good, had them replaced 20,000 miles ago and there is no movement. The spring is good too. I checked all of my external components before I posted this thread (ball joints, suspension, steering, drive shafts, u-joints and even pulled my hubs apart to check the wheel bearings and outer shaft bearing. I was able to check out my shafts where they go into the front diff and the races look perfect. Checked my gear lube level and it still looks new, its been changed 10,000 miles ago.
The more I think about it, it seems like something wrong with the limited slip in the front diff? The pinion shaft felt fine, I can turn the gears in the diff and everything feels smooth and quiet. I checked the U-Joints on the front drive shaft and in both axel shafts, all feel fine. The noise I am hearing is a loud grouling noise that get louder with wheel speed, sounds like lots of gear noise. This only happens when the front hubs are locked in with the transfer case in 2wd or 4wd high. 4wd low I cannot get the wheel speed fast enough to hear it.

I have not pulled the front diff cover yet, If I do is there a way to test the limited slip?

 

[496truck]

Unless you have installed a limited slip diff in the front axle, it should be an open diff. And now that I think of it, are the brake calipers hanging up and dragging? One side holding pressure would cause the other side tire to spin backwards under a no load situation, like on jack stands.

Also check the front drive shaft from the t-case to the front axle. The u-joints or the CV portion and maybe even the slip shaft could be worn and making noise.

 

[urbanburban91]

Thanks, The brakes are not hanging up. I am clearly over my head on this one, you are right there is not limited slip in the front end to my knowledge. I am going to take it to a friend that works on these things. Even if i could figure out what is wrong, I have no experience working on this park of my truck. Still open for ideas on whats wrong with this thing, I will keep you posted as I know more.