clunk goes the tcase (1 Viewer)

[topherbecker]

Pulling into the office garage this afternoon, I start to hear a creaking/groaning/binding noise as I come out of a turn. Sounded a little like my creaky springs except the noise continued at a dead stop and even after shifting into neutral. Couldn't isolate the location of the sound since it went away before I could get my radio turned down and get the hood popped. So I put it back into drive, sound is gone, I do a three point turn and when I go from reverse to drive, I get a nice "CLUNK"

Got one of the building engineers to shift R/D/R/D for me while I go under to inspect (in the dark), and I feel the clunk as if it's coming from the back of the transfer case. Not helpful, but I couldn't see much of anything else. We were just in the tcase a couple months ago (replacing the tranny/tcase seal), and the tranny output gear had little to no wear, so I don't think it's that. It doesn't leak, and it's been driving fine since we were in it.

Any ideas?
-chris

 

[John Smith]

Start with the easiest thing and drain the transfer case to see if you have a metallic glitter fiesta or a normal amount of metal sludge on the drain plug.

 

[Von Hayek]

Well that's no fun. Hope it's not too serious.

 

[OTRAMM]

If it continued after you put the truck in neutral I would think it would be in the trans of forward. Nothing spins in the t-case when you're in neutral. Unless you were still coasting.

 

[topherbecker]

I have no clue what the initial creaking noise was. Haven't been able to reproduce it.

Got home, jacked up one rear tire, and put her in neutral at the tranny. plenty of oil in the tcase (80w90 if it matters), and looked normal, honey. I did not drain, but can do that this weekend. Ujoints have no play. Spun the driveshaft and heard nothing unusual spinning it forward. There was more play than i expected before the gears engaged, but i have nothing to compare to - it may be within spec. I did notice that when i spin the driveshaft in reverse, i hear 'marbles'. I also noted that i could spin the driveshaft forward easier than i could in reverse; forward, i could spin it so that the rear wheel would continue to spin for maybe a full rotation, but spinning the driveshaft backward did not get the same momentum effect. Not sure if that means anything, probably not.

I'm kind of thinking the clunk has always been there and i never noticed it. Have I really never shifted from Reverse to Drive with the windows down? Hard to believe, but possible. But that still leaves the weird binding/creaking noise, or whatever it was. It was definitely still audible after i put it in neutral and no, truck wasn't moving at all. i got out of the truck to pop the hood and first thought it might be a rattling noise coming from my downpipes/exhaust/heat shield. For whatever reason the other thing running through my head was the steering gearbox. But by the time i got to the front and popped the hood, the sound was gone.

i'll update if i hear it again.
-b

 

[Stumpalama]

Unbolt the driveshaft from the rear axle and try spinning it and wiggling it around its range of motion. You could have bound a u-joint and it's only a matter of time before it implodes.

 

[bkfj40]

Most of the auto cruisers that I've had do have a clunk when shifting from R-N-D

definitely check the u joints....just to make sure, your hubs were unlocked, right?

 

[Stumpalama]

Have you checked your knuckles? Are they oily? sometimes they can begin to make noise and the clunk could be unrelated and coincidental.
My FJ62 had an occasional clunk when taking off after shifting from R to D or vice versa. I took it to a shop and they told me the transmissions can have some lash in them. They also told me they were bulletproof, were used in Hino dump trucks and the only time they saw issues was when the transmissions got water in them.