2000 Blazer clanking in 4x4 only
 

Hello, I am new to posting to these forums but I have read several posts and cannot find a similar issue.

I have a 2000 s10 Blazer, non zr2. Driving in 2wd there is no noises or clanking. When I switch to 4x4, it engages and runs fine on flat ground. As soon as I start climbing an incline, I hear a consistant clanking pop from front end, worse the steeper the hill it is, 4lo and 4hi. I can back up the hill and hear no problems. I drive up the same hill in 2wd, no problems. Does not clank when I turn left or right in either 4x4 or 2wd on flat ground.

I have replaced upper and lower ball joints, inner and outter tierod ends, wheel bearings, cv joints, callipers and pads, and rotors on both sides of the vehical. I also replaced the idler arm. The front drive shaft has been balanced with new u-joint and cv joint.

This blazer is not stock, has a 5" lift and I installed a powertrax locker in rear as well as rebuilding rear end. Also been regeared some time back.

I am completely baffled and can't find a solution to this, any help would be much appreciated. Thanks, Eric.

my first thought would be the transfer case could be goin...just goin with the idea its lifted and what not its probley gone mudding once or twice and possibly gotten water in the Tcase and yaaa lol ....check your fluids in there (make sure there is some could have had a leak and not known it and run her dry too) and if it looks low or dirty change it with some fresh 80/90 and see if that helps at all as a first test before you go replacing your transfer case

Thanks for the quick reply. I will be checking the fluids soon. I was just crawling around under it and noticed something kinda odd aswell. It seems as if the whole front end is moving. I can see rub marks on a cupple spots as well as the oil pan where it looks like the axle has be coming in contact with it.

I pulled the front drive line and noticed strike marks on both sides of the u-joint housing, maybe the noise I'm hearing? Being lifted the driveline sits at a different angle then stock. Possibly bad bushings on the front end?

your axle hit your oil pan?....do you have a soild axle in the front?

I still have IFS. The front axle has brakets that drop it down so the angle on the cv shafts isnt extreme. What I'm thinking is happening is under load in 4x4 the front axle is moving down causing the u-joint to be at to much of an angle because the bushings for the axle are worn. I hope this is the issue but I'm not sure yet. I'm gonna strap the yoke up tight and wheel it today or tomarrow, see if I hear anything.

alright well if you figure it out make sure to post it cuz i wanna know now lol =P

Hey Erictd,
When you check you fluids in the front diff see if it has any metalic particles. Also, the transfer uses dextron atf. See if that fluid has any metalic stuff in it as well, either case is bad news.

Thanks for all the help. I will be checkinag and changing fluids tomarrow. I made a 1"x1/2" black iron nipple and jammed it inbetween the mount directly under the front yoke preventing the axle form moveing downward, test drove and deffinitely seems to be an improvement. I think the axle is still twisting too much. So it looks like new axle mount bushings are in order.

This might not be a very common problem on stock blazers because the driveline isn't at such an angle. So now it looks like I'll be droping the front axle, but what Im not sure of is if I can remove both half shafts at the same time? I"ve heard that on some vehicle's the gears will fall into the case if both half shafts are removed.

As far as my axle hitting the oil pan, the drop brackets for the front axle to be lowered 2", are offset to the back of the vehicle pushing the axle closer to the oil pan then it would be stock. My driveline is also shorter