Loud clunk shifting from low range to high range

[OakieEd]

After successful shift from any low range to any high range (indicator light at shifter knob shows shift complete) when I start to move forward (straight on level ground) there is a loud clunk from somewhere under and behind (I don't know if it is transmission, transfer case or differential etc.) The clunk is loud and strong..like when something binding just broke free. Thoughts? After the clunk...the truck seems normal in high range.

 

[Jeepwalker]

I would put it up on jackstands and have a look around for:

1. U-joint wear/freeplay
2. Front CV's worn
3. Front axle actuator flaky or intermediate shaft bearing issue
4. Axle intermediate shaft freeplay or problems. Video HERE
5. Front/rear driveshafts/U-joints (just wiggle the VIGOROUSLY). Observe for freeplay.
6. Transfer case electric actuator. You may be able disassemble and lube.

Probably #6 or #3 You might pull off the xfer case actuator and inspect. There are videos on it.

 

[OakieEd]

I checked as you advised. What I found was the transfer case was half empty. Put in .7qt of lubricant and it shifts fine now. No sign of any leak. I think I'm hearing alot of noise out of my transfer case now. Quite alot of whine at 53-56mph. Any ideas?

 

[huntergreen]

Did you also check rear diff fluid level ? It’s probably fine but it’s worth checking.

 

[OakieEd]

Yes. Rear diff full