Clunking while in 4wd going up hills

[wildbill23c]

Transfer case is just bolted to the back of the transmission if I recall. The clunking is only happening in 4WD so I'd suspect some 4WD component(s) as the rear drive shaft always bounces around even if you aren't in 4WD when driving down the road its going to bounce along with your axles as you drive over bumps everything moves.

Put the Go-Pro up front under the front bumper facing towards the rear of the truck on the passenger side, test drive, then do the same on the drive's side. Maybe a better idea as to what's going on that way.

If the rear diff is rotating then something in the suspension isn't tight causing the axle to be able to turn slightly, that's not a reason to replace springs, it means some bolts need to be tightened down. Could also be bad u-joints causing the driveshaft to thrust itself upwards as the u-joints are probably sticking and not rotating properly.

 

[osujason]

Transfer case is just bolted to the back of the transmission if I recall. The clunking is only happening in 4WD so I'd suspect some 4WD component(s) as the rear drive shaft always bounces around even if you aren't in 4WD when driving down the road its going to bounce along with your axles as you drive over bumps everything moves.

Put the Go-Pro up front under the front bumper facing towards the rear of the truck on the passenger side, test drive, then do the same on the drive's side. Maybe a better idea as to what's going on that way.

If the rear diff is rotating then something in the suspension isn't tight causing the axle to be able to turn slightly, that's not a reason to replace springs, it means some bolts need to be tightened down. Could also be bad u-joints causing the driveshaft to thrust itself upwards as the u-joints are probably sticking and not rotating properly.

 

[osujason]

I probably need to put the Go-Pro down there for a second look, but based on what I saw the the first time, there has to be an issue somewhere with the rear driveshaft, rear diff, leaf springs. Like you said, it could be the u-bolts, or something needs tightened down on the rear suspension. The only strange thing to me is why I only hear the clunking while in 4wd, which is why I initially spent all this time looking at transfer case and front end area. But it does sound and feel like it is coming from the rear and the video footage from Go-Pro confirms this. I have actually already ordered the leaf springs, but I'll get under rear end and see if any thing needs tightened down on the rear suspension and I'll look at the ubolts on rear the drive shaft before i mess with putting the new leaf springs on there.

 

[osujason]

I put the new leaf springs, shackles and u-bots on. Took me several days. The ride does feel stiffer and seems to have minimized some vibrations that were occurring at highway speeds. However, the clunking while in 4wd is still occurring when going up hills. So now I'm looking at u joints and drive shaft angles. The picture below is the front drive shaft connecting to the transfer case. Does that angle seem to much? I did not get a chance to measure, What is the proper angle coming out of the transfer case to the front drive shaft. Also, there is no lift on the truck, should be pretty much stock. Could bad engine and transmission mounts cause these angles to be off?

 

[Fire]

Old thread. Hope you got it figured out. I had something similar a few months ago.

Turned out to be the transfer case shift fork was only partially engaging 4x4 mode. It would pop in and out of 4x4 with viole tly banging noise. Ended up swapping out the mode shift collar.

Im gonna do a write up on it, just havent gotten to it yet.

 

[wildbill23c]

I put the new leaf springs, shackles and u-bots on. Took me several days. The ride does feel stiffer and seems to have minimized some vibrations that were occurring at highway speeds. However, the clunking while in 4wd is still occurring when going up hills. So now I'm looking at u joints and drive shaft angles. The picture below is the front drive shaft connecting to the transfer case. Does that angle seem to much? I did not get a chance to measure, What is the proper angle coming out of the transfer case to the front drive shaft. Also, there is no lift on the truck, should be pretty much stock. Could bad engine and transmission mounts cause these angles to be off?
View attachment 47945

Those CV type joints are probably part of your problem, those things are horrible when they fail, all sorts of noise, my 88 Bronco 2 had those when I got it, when I had the transmission rebuilt I had them send the drivelines to a shop and have them rebuilt with U-Joints. Expensive but worth it to get rid of that CV joint garbage.

 

[osujason]

I have had both the cv joints replaced in the last 2 years, didn't seem to make a difference. So I don't know where the clunking seems to be coming from, but I decided to just let it be and if something eventually breaks, I can fix it. Until then, I will just keep wheeling.