Severe banging, knocking...Front end/transfer case?

[ComancheKid45]

Alright fellas, I know the whole "fix my noise" approach online isn't always the best but I'm just looking for anymore opinions.

 

Anyway, 88 Aw4/231. Just finished up a transmission and transfer case swap and now have a severe bang/knocking. With the truck on stands and in 4wd it only occurs when hitting the brakes, when driving it occurs when turning and under acceleration. So far I've checked out these parts.

 

Reset and adjusted transfer case linkage

 

Tore apart front diff and examed internals, including, ring, pinion and Spartan locker as well as both axle shafts. Nothing abnormal

 

Fluid in t-case is full and fresh

 

Fluid in ft diff was water contaminated and was swapped, new fluid was also very milky after being in there for a few hundred feet, fresh fluid will be used upon reassembly

 

Axle shaft u joints are both tight and clean, lf is brand new along with shafts.

 

Transfer case was working fine from the previous owner and I have no issues from it in 2wd on the jackstands.

 

 

So that's where I am, anyone have anything else I should check out?

[ParadiseMJ]

Did you have a different (manual) transmission before this, or is it just a newer AW4?

[ComancheKid45]

Swapped Aw4s. Installed a 23 spline version from a 95 XJ along with the transfer case from the same Jeep.

[yxmj]

First guess is your chain is slipping....

[ComancheKid45]

Yeah, after tearing apart the front diff I'm leaning towards something ary inside the transfer case...

[yxmj]

Well look at your post of when it occurs...when braking and when you put the gas to it......both those load the chain... :dunno: ......no noise in 2wd unless you turn....with a locker it would reverse load the chain...find some loose sand gravel snow...put it in 4H...put your foot into it.....is there a bang?

[ComancheKid45]

I'm sure there would be, everything else points to the t case. Interesting fact on the locker putting reverse pressure

[1987Comanche]

disconnect the linkage, manually shift the T-case to 4HI, go for a drive, and see if the noise is still there.  I though the 231 I swapped in had major problems until I tried this.  Turned out the jy that pulled the T-case subtly bent the linkage.

[poopypants]

Find some loose sand gravel snow...put it in 4H...put your foot into it.....is there a bang?

This ... Also when my chain finally stretched enough to start jumping teeth you could hear it dragging along the bottom of the case just driving around in 2wd....just something else maybe to listen for proving a stretched chain

[ComancheKid45]

I was hearing something very similar to that while running the truck on stands....I ordered a chain and such this evening. I'm very confident this is where the problem lies.

 

Thanks fellas

[ComancheKid45]

Tore apart the transfer case and sure enough the chain was shot, tearing up the pump filter and all. After replacing the chain all is perfectly fine. Thanks for the input guys.

[mik666]

awesome!