Friends,

Over the past ~500 miles, the clunk sound has increased a lot. Previously it was something that was barely audible but it has become quite loud and irritating now.

This is what I have done on my zuk in recent past (after which the clunk nose has increased):

- 4.16 tcase gearset
- 235 tyres
- new shocks in front


Now the question is how to nail down if this is due to bad U-joints, CV joints, or backlash or something else.

It comes when I press clutch, change gears or let go of the gas pedal. And yes, it comes in every gear change.

NOTE: the clunk sound doesn't come from the rear (or the lockers). It is from the front ONLY

If your hubs are unlocked and your in 2wd it shouldn't be anything to do with your front end, as it is static.  Possibly your jack shaft between your Transmission and the Transfer case.  I would see if the U-Joints are sloppy.

Same with your rear, your upper one might be going and the noise is just travelling through your drive line.  I take it your transfer case shifter is not moving when you take off?

If your hubs are unlocked and your in 2wd ... 

No. I don't have hub locks and they are permanently locked. So even in 2wd the front is NOT static

Possibly your jack shaft between your Transmission and the Transfer case.  I would see if the U-Joints are sloppy.

How to check for this? what to keep an eye for here?

I take it your transfer case shifter is not moving when you take off?

Good question. Yes the t-case shifter does move slightly. In first gear the 'Main gear shifter' does seem like taking off. Not so much in other gears.

I have checked the t-case arms/mounts and they are perfect -- nothing loose here.
 

I'm gonna go with motor mount.


Have you tried putting the truck in gear, engine and e-brake off, and having someone rock it back and forth?  I expect you'll be able to hear the clunk and track it down that way.

Check the u-joints by getting under the truck, and twisting the drive shaft by hand. Look for any play in the u-joint, and listen for the clunky noises.

Your T-Case shifter really shouldn't move more then 1/2 an inch at most.  Any more then that and you probably broke the upper T-case mount.  It could be making noise from hitting the bottom of your Gypsy.

When your checking the U-Joint in the Jack shaft see if there are small dents in the body on top of your upper T-Case mount.

One thing to try is pulling your front drive-line real quick, that will tell you if that's part of it. 

Ok folks, thanks for the inputs. I will do the checks as mentioned by you all this weekend and update you all with my findings.

Cheers,

Ok folks,

got this done with. The clunking sound was from the T-case jack shaft U-Joint. It had lots of play in it. Got it changed and the sound is now gone.

Thanks for all the inputs.

Now, one more question. While checking this, I tried to twist/turn the front/rear drive shaft wuth my hands and here are the findings:

I was able to turn the REAR drive shaft approx 1" (or approx 1/10th of the turn) with my hands

I was able to turn the FRONT drive shaft approx 1/2" (or approx 1/20th of the turn) with my hands

There is NO play in the U-Joints etc parts.

Is this OK? If not, what should be the ideal scenario?\

Cheers,

Good to hear, 9 times out of 10 its a u-joint.

happy wheeling

Glad to hear you found the problem.    Remember, when replacing a U-Joint replace both ends a the same time.  Otherwise the second half will end up going out and destroy the new U-Joint along with it.

You should be fine on the slop level in the drivetrain.  The difference between the front and the rear is probably due to your locker.  The only way to really check is pull the diff and make sure that the gears are still within spec.

I was able to turn the REAR drive shaft approx 1" (or approx 1/10th of the turn) with my hands

I was able to turn the FRONT drive shaft approx 1/2" (or approx 1/20th of the turn) with my hands

Certain gear packs (t-case and diff for sure, maybe manual trans too  ) are designed to run with some "slop" in them. I don't know how much is "normal" though 

We have 5-6 zuks in our group and what I will do is check for the 'slop' in them. All of them are FULL STOCK.

That would be the most easy way to find out.

Cheers,