NP231 Transfer Case rebuild?

06TJX · Apr 21, 2015

So I have a wicked sound coming from my undersides when I put it in 4wd...I loose power to the front wheels and a clicking sound that could be a chain skipping its cogs maybe? I can get get audio tomorrow, but its not good. i have a SYE.

Any ideas on the cause??? Id like to tackle this but wanted your take on what is happening..

97TJGUZZY · Apr 21, 2015

Sounds like it is possibly not engaging fully. Have you had this problem since you installed the sye?

06TJX · Apr 21, 2015

nope. It started recently. It not a grinding sound, but ratcheting...its weird. Last fall I put it in 4wd for the first time in a year or so, and it made the sound, and i thought it was the lockright. Then when we put in the 8.8 and tried to drive in 4wd without the rear driveshaft, it did it again, and that is when I realized it wasnt pulling...it would pull a second, then skip...Then today, after rebuilding the d30, i just tried 4wd and it continued.

I have not tried 4low, I just dont want to do any more damage. I know they are not complicated, but something is def. not right

is this what happens with a loose chain?

97TJGUZZY · Apr 22, 2015

I don't know that the chain can get that loose. Even a loose chain will pull, it's just loud from rubbing on the case.

06TJX · Apr 22, 2015

Yeah...I am starting to go back to thinking something ain't right up front. I called the mechanic and the aussie is dead to rites spec wise, even called aussie to confirm. Aussie recommended the cross pin be replaced and verify tire pressure and that the axle isn't bent...

Any good ideas on how to verify the axle is true?

matth_85 · Apr 22, 2015

I've seen Chevrolet trucks where the chain gets so loose it will slip like he's saying. But typically they have a hole in them allowing more slop...

jp fan · Apr 22, 2015

If the axle is bent you would see funny tire wear and would not track straight, I would pull the plugs on the t-case and see if there is any metal same for rear diff

06TJX · Apr 22, 2015

The rear is getting dumped next week as it is finishing up its 500 miles of wear after the new axle went in. The banging clackity clunk sound is def. coming from the front. I will do the trans case at the same time. I need to replace the output seal anyway on the SYE as it is leaking a bit.

I am going to order a cross pin and stick that in there and see if it make a difference, and verify the tire pressure is right. Can you replace the D30 cross pin without pulling the carrier? I know there is the roll pin holding it in place, but didnt know how difficult it would be to do with the carrier in the axle and the shafts in place....

97TJGUZZY · Apr 22, 2015

06TJX said:

should be able to pull the cross pin with the shafts in if your gears are higher than 4.10s i think. If you have 4.88 or 4.56 it may be hard to get the pin out without removing the ring gear. Its been a while since I messed with a 30. But on that note, I dont think the crosspin is your problem.

06TJX · Apr 22, 2015

Well its a cheap fix. I am gonna throw one in next week and see. Ill also rebuild the shaft u-joints and make sure those are not the issue.