I have been fighting a persistent problem for a long time now. My tranny began to make a sound as if a gremlin was inside banging with a hammer. This becomes very prominent gears 3 and 4. Tranny shifted well. Rebuilt tranny with new bearings. All gears looked great. No sign of trouble/damage. Still sounds like the case is being pounded by a hammer. Only occurs under a load. When wheels are off the ground, I can shift through all gears with no issues. I took the front drive gear cluster out of the NP205 because I was running out of ideas! No change. NP205 looks good. What am I missing? Posts a long time ago had the same problem even had a video but never found a follow up. Next step is to drive the out of it till the problem reveals itself. ????????
Thanks!

 

Something to try: Put the shifter in 4x4 and remove the rear drive shaft. Drive it around as a front wheel drive and see what happens.

Worst case is you know the problem is not the rear drive shaft and likely not the rear dif.

JP.

 

I have a post a while back about my getrag rebuild. Mine was popping out of 3rd gear. Finally third gear went out. I looked over that trans for 2 days trying to find something. Only some minimal wear on the scynchos for the 3-4 gears. I was putting it together and was 10 seconds away from missing the problem. The sycrho teeth on the 3rd gear broke clean off in a ring and it looked perfectally normal. I found it when I was putting 3rd gear back on the shaft durning the assy. Not the same problem but if it happened once it could happen again.

 

Are you sure its in the trans and not maybe the clutch under load ?