When driving in 2wd or 4wd and while under power I get a very loud popping noise. I can't localize it while driving but I thought it was a gear slipping in the rear end, I pulled the diff cover but the fluid is pristine with no metal in it and there's no noticeable damage to any of the gears. Could the noise be coming from the transmission or t-case or could a gear be slipping in the diff without leaving any marks or metal in the fluid?

 

I pulled the rear drive shaft and drove it in 4wd, it's still making the noise. So I know it's not the rear diff, and I'm ruling out the front diff/u-joints since it only makes the noise when under power. I'm going to drain the fluid from the transmission and t-case to see if there's any metal in either fluid.

 

Could be in Tansfer case or trans. On a flat surface see how much play your output shaft to your transfer case has with the rear DS out. If you have a lot of play it might be worn real bad inside.

 

i would check your motor and transmission mounts, this will definitely cause this especially under load. broken transmission mount is a very common player in this problem, especially with the manual transmission.

 

The engine and transmission mounts are urethane and only a couple years old with no noticeable damage. The drive shaft did have a lot of rotational play when I had the rear end jacked up, but it was in neutral, I'll check it again with it in park. If there's still rotational play in the drive shaft with it in park, would it most likely be a problem with the t-case or transmission?

 

The popping noise sounds like a gear is slipping a tooth then catching on the next, it's a very 'powerful' noise that shudders the whole jeep.

 

I pulled the cover off of the t-case and there's small metal chunks caught in the filter, so I guess that's my problem, lol. I'm going to search craigslist for a t-case or just go to the JY and pull one. While I have the t-case off, is there any mods I should do? I thought I read before that you can swap in a beefier chain or planetary gears from a blazer or some other truck.

 

You might want to crack it open. The chain might just be loose from just stretching over time. If it hasnt been too long you can change the chain out for another newer one about 80-100 bucks.

EDIT: wow I misread you did actually crack it open. Anyways checking the chain to see if its replacable might be worth the trouble.

 

I'm going to the JY tomorrow, I'm going to look for a np231dhd on a Dodge Ram. If I can't find one I'll just pull a np231 from a jeep. I just really want to get this thing running again so we can get some camping in and so I can finally start rebuilding my Seafair Sedan