04' Sierra Transfer Case Noise

hitempguy · December 3, 2008

My 04 Sierra Crew Z71 125K, makes a whining noise when I switch to 4High. It seems to be directly related to speed. The noise gets louder, sooner when I activate 4low. There is no noise in 2wheel drive. The oil was changed in all the diffs and transfer case(using the blue OEM oil in the Tcase and OEM in the diffs) Any ideas or anybody had this issue??

merlin5577 · December 4, 2008

My 04 Sierra Crew Z71 125K, makes a whining noise when I switch to 4High. It seems to be directly related to speed. The noise gets louder, sooner when I activate 4low. There is no noise in 2wheel drive. The oil was changed in all the diffs and transfer case(using the blue OEM oil in the Tcase and OEM in the diffs) Any ideas or anybody had this issue??

Have you checked the fluid level?

mrmike38z · December 5, 2008

I just had to replace my transfer case. It was making a chain rattling noise in 2wd and a slight grinding noise in 4wd. The rattling was the chain in the transfer case. They put a new rebuilt one in with a 3 year warranty for a measly $1800.00. You might have your local transmission shop that you trust look at it. They said the chain had almost wore through the housing.

green 788 · December 5, 2008

How long after the oil was changed did this noise start?

hitempguy · December 6, 2008

the oil level on the tcase is full, I tried topping it off until oil ran out the fill hole, then took it for a test drive. Whining sound still there. The oil that came out when I filled it, looks quite black, this is after about 10000 miles??

i'm unsure when the sound started, it was late spring when I changed the oil and I didn't use the 4wheel drive for a while after the oil change. It has been a while 3-4 months since I first noticed it, but since I rarely use it, I didn't worry about it. But now we have snow and ice.....

hitempguy · December 7, 2008

OK, I changed the oil in the tcase and front diff. After a test drive, it seems like the whining noise is coming from the front diff. The front diff also makes a groaning noise when slowing down or turning while in 4wheel drive. The oil was still looked new, but has a lot of sparkle from something metallic in the oil. Is there a common problem or solenoid problem with these diffs. The truck has autotrac, but if I need 4wheel drive, I will select the hi or lo manually

hitempguy · February 28, 2009

Ok, I finally got the tuck into a trans shop. They put it up on a body lift and ran the truck in 4WD. The whirring/whining sound IS coming from the T-case, in 4-HI & 4-LO. The noise does not seem to be load dependant, just increases as speed increases. Autotrac works fine, starts whining if there is slippage and the Autotrac engages, stops when disengaged. No noise in two wheel drive. The shop has never heard this sound before. They are guesstimating $300 - $800 to fix, plus 400R&R, if it is a major failure $1800 plus the $400 R&R.

Changed the oil again and the oil is clean (4000Miles)

Has anyone heard this type of noise before?

Also is this a TCase that is affected by the pump case wear issue (4WP-TC246G-3)

If the T-Case is pooched, would I be better off buying a rebuilt off ebay?

Ebay t-case

Thx for the assistance

green 788 · February 28, 2009

You might be able to find a used transfer case, but unless it's really cheap (say, 500 dollars) it's probably not worth taking the chance.

A rebuilt with warranty would be a possible option.

This latest generation of GM transfer cases seem extremely prone to crappin' out unless they are meticulously maintained. Read the archives here... they'll get a little hole in them from the oil pump shaft and they'll start leaking oil, then the next thing you know they're low on oil and cooking the bearings.

Just change the oil often, and always watch for drips and dribbles on the driveway under the truck.

None of this is to say that your TC had the oil leaking problem. But that is the most common problem, it seems.

Good luck. You're not the first owner to have problems with this generation of transfer cases, and I'm sure you won't be the last. But again, once you get her replaced or rebuilt, change the oil often (maybe every other oil change, or if it were mine I'd just change it EVERY oil change).

GM has this special oil they've specked for these TC's, but I wonder if that couldn't be part of the problem as well. Their Dex-cool anti-freeze turns out to eat intake manifold gaskets (though you'll never get GM to admit it). So they could have cooked up a lubricant for the TC that's less than ideal. Just thinking out loud here... not preachin' the gospel!

If there's an acceptable alternative lube for these transfer cases it might be worth exploring. Check the boards at www.bobistheoilguy.com and see what's offered, or ask an Amsoil dealer what he can offer.

Dan