Transfer case issue ?????

**92 Burban** · 05-06-2009, 12:40 PM

Help!!!
Well I was driving home from work the other night when the burban started sounding like a jack hammer. I thought it was the rear end but I put it in 4wd & pulled the rear drive shaft & it would not go anywhere & made a high pitch noise. I put the shaft back in & it would go forward & backword but it still clunks.

Am I on the right track??? Any thing else I could check????? Where can I get a replacement?

**bry2500** · 05-06-2009, 03:23 PM

My 02 Avalanche is making the same noise. I just noticed it as I went from one building at work to the other. I hope it's not the t'case. I'm hoping low on fluid in the front diff or t'case. i can't afford to replace one right now. I'm hoping it the early signs of a ujoint even.

**TUTONE** · 05-06-2009, 04:11 PM

Could be the planetary gear going out in the tranny. My '90 burb did the same thing. Had the tranny rebuilt and changed the lockout hubs immediately afterwards. Mine had the automatic locking hubs and I don't think they were unlocking all the way which is bad for the drivetrain driving 20 miles to work at 65 mph every day. I haven't had a problem since. I'm not sure if the hubs caused the damage to the tranny or not but I wasn't taking any chances so I changed them. Besides, I like having the control of the manual hubs more than the automatic hubs. "If you want something done right [like unlocking your hubs] do it yourself." Changing the lockouts was actually pretty simple too. If you do decide to change your lockout hubs, check your wheel bearing nuts and bearings while you're at it. Make sure they're properly torqued and greased. My front passenger side bearing was quite loose.

**bry2500** · 05-07-2009, 03:26 AM

went under the truck yesterday and found that the front drive shaft u joint to the transfer case was nearly in 2 pieces. got 2 u joints now just need nice weather to do the job. I hope this is my noise and not anything else. I am gonna pull the shaft and drive around without it to see.

I hope you have an easy fix on your hands too.

**92 Burban** · 08-05-2009, 10:47 PM

Well I have disassembeled the case and I cannot see any obvious signs of what was banging around. Has anyone had a problem with the trans chain streaching? Would the range fork pads moving cause the noise?

I was hoping for an obvious sign but its never that easy.

**2COR517** · 08-06-2009, 12:26 AM

Originally Posted by TUTONE

Mine had the automatic locking hubs and I don't think they were unlocking all the way which is bad for the drivetrain driving 20 miles to work at 65 mph every day.

Even if the auto hubs didn't unlock, it wouldn't have any impact on the transmission if the case is in 2wd.

As for bad for the drivetrain, that's very debatable. GM and others had full time 4wd on many vehicles for many years. You couldn't unlock the hubs on them if you wanted to. And the newer autotrac cases have the entire front drivetrain rotating all the time.

**92 Burban** · 08-06-2009, 01:58 PM

I have read that the Transfer case chain can stretch and bang in the case. Could this be it? The U joints look good old but good. I was thinking about putting the case together without the chain and checking it. But I'm not sure what to do.

**Jimmiee** · 08-06-2009, 04:17 PM

The chain would only make noise in 4WD. In 2WD the chain is not turning or if it is it's just going along for the ride.

**92 Burban** · 08-10-2009, 09:17 PM

Thanks All,
I think the noise is in the rear end & thats what I will be looking at next.
Also the NP241 is easy to rebuild as long as you know what end of the socket the bolt fits you will be fine & it can be done still in the truck. If anyone need help I can walk you through it.