Noise in NP231 after SYE install

Hey all-
I installed an Advanced Adapters SYE and a new Tom Woods rear drive shaft on my NP231 about 6 months ago and all seemed ok. I then re-geared and had my D44 put in the rear and started to get some knocking noise. Ran through the gears with the t case in neutral and no noise. Pulled the rear shaft and ran in it in 4hi and 4lo with no noise. As described it is a knocking noise that is very light under acceleration, almost non-existent, but is much more pronounced under deceleration, especially in 3rd gear. Before I tear it apart/rebuild, anyone have any ideas? Any help is greatly appreciated.

Thanks!

Did you shim the rear axel? Pinion needs to be pointed right at the double cardan joint

No shims. Rear axle perches were set and welded for correct pinion angle. It's pointed right at the cardon joint. I had the stock D35 shimed before the axle swap and no issues.

From your description it sounds like it may not be a t-case problem.

At 6 months after a gear change it wouldn't be a bad idea to pull the shaft completely and check your rear pinion for play and/or to pull the gear cover and look around. Accel/ Decel noises can come from the pinion preload changing, though it is usually a growl, not a knock.

How does the shaft feel? Particularly​the CV portion? If you pulled the shaft and the noise went away I'd start there.

Do you have a u-bolt style pinion yoke? If so, how tight are you tightening the nuts?
What did your pinion end u-joint look like?

Its really easy to over tighten the u-bolt style u-bolts, and crush the u-joint cap slightly, which leads to significant wear on the needle bearings in the cap in a hurry, which causes a clunk when going from loaded driveline to unloaded (acceleration then deceleration).

Something to look at anyway. Only need like 15 foot-lbs or something, which is really easy to blow past with a box end wrench.

I have u joint straps, torqued to specs. I just pulled the rear shaft and the cardan seems fine, no slop, same with the rear u joint. The pinion has no play. When I get the knocking noise, I can push slightly forward on the t case lever and it seems to not be as loud, but still pretty noticeable. I have a boostwerks linkage so I am going to try some adjustments on this for one last try before I drop the t case.

Was the chain stretched at all ??

Accel to decel swaps the location of the slack in the chain from bottom to top, that may be what you are hearing if it was loose.

Try this........get the jeep in the air, then put it in gear, and rock the driveshaft back & forth as best you can.....is the noise you hear when swapping direction of driveshaft rotation that same you are hearing upon decel ????

Doing this simulates accel to decel load changes, and will accentuate any slack in the tcase chain.



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So you changed the rear axle and immediately got a light knocking noise?

I wouldn't dismiss the TW shaft.