lokoh

So the transfer case on the 2002 AWD Denali just blew. I took it to my mechanic and he seemed to think that the cause of the failure may have been due to the regearing of the truck when I had it lowered. I went from 4.56 front and back to 3.73 front and back. Keep in mind, this was about 8 months ago and I have driven the truck approximately 8000 miles since the re-gear and I got regeared at a very reputable drivetrain shop here in socal.

WTF? If the front and rear had different gear ratios, how the F could I drive it for 8000 miles? Wouldn't it just lock up immediately since it's AWD? Am I missing something here. I even asked my mechanic straight out - "Could I drive the truck with completely different gear ratios in the front and back for 8000 miles?" He said I could but that's probably why my transfer case finally gave out.
Don't know much about transfer cases, but could this even be possible? what are some common causes of transfer case failures? BTW the denali is now lowered 5/7 on 24's. I've been going to this shop for the past 4 years and they've always seemed to do good work in a timely and reasonably priced manner. After this, I may consider changing shops. Any help is appreciated. Thanks.

Bumpers

iTrader: (10)

being full time awd i doubt it woulda made it with 3.73 and 4.56s in the front and you would have def been able to tell while driving it. what broke in it?

1Bear

iTrader: (1)

I'm not going to say that you did drive it with miss-matched gears and was the cause of your issues, but due to the AWD transfer-case in your year model being a NVG-149; it may be possible to drive a certain distance before failure with miss-matched gears. Your style transfer-case has a viscous coupler and is not hard linked like a true 4WD and could slip due to the axles turning different speeds. If this is truly the case, I would believe you burnt up the viscous coupler. If you were to attempt the same thing with a true 4WD; the vehicle would bind up and try to hop around.

lokoh

So I got the transfer case rebuilt. It was the viscous coupler that failed. I asked the shop to spin the wheels and "check" whether the front and rear may have been regeared differently. He said that he spun the driveshaft less than 4 times per rotation of the front tires. For the rear, he spun the driveshaft more than 4 times to get one rotation of the rear tires.
So it appears that I may have been regeared differently, right??
Possibly 3.73 in the front and 4.11 in the rear?
My wife drives this truck about 15 miles each day to and from work. I don't think we've driven more than 40 miles 1 way at a time. By driving short distances and allowing the case time to cool, could this explain why we were able to go 8000 miles with mismatched gears?

I'm gonna have my wife's shop take off the rear diff cover and count the teeth to see if they are 4.11s in the rear.

I called the shop that installed the gears and they looked up the order and they said the front/rears are the same. They offered to pull the front and rear to check (they would charge us for this I assume). If indeed they are mismatched, I would want that shop to pay for the repairs on my transfer case. However, if I have them check and they correct the mismatch without telling me, they could just say that they were not regeared differently. I doubt they would want to admit that the put mismatched gears in my truck.

Mistakes happen, I can accept that, I just want this fixed and to be reimbursed for all the repairs. I'm not saying it's they're fault. It's possible the gears were boxed incorrectly from the manufacturer and the installer didn't count teeth before install.....
Argghhhh this has been on headache after another.

skoal bandit

iTrader: (1)

Ask to be present when they check the gears. they should atleast let you stand outside the shop and watch them tear it apart. It seems obvious they are different gears. They might still say it wasn't them. They might try to say that you must have changed the gears after it left the shop.

lokoh

Update...
So my wife's shop pulled the rear diff cover and counted the teeth. Sure enough, the gears were 4.11s!!
Called the shop that re-geared it, they didn't believe it. They wanted my wife to tow the truck there to have it inspected. She bitched them out, so they sent one of their employees to come take a look at the truck.

When the guy arrived, he knew right away they have regeared the front and rears differently. He apologized for the mishap. Apparently, they had one employee regear the front and another do the rear. They said this has never happened to them before and that they're surprised I was able to go 8000 miles before the **** hit the fan.

The shop agreed to tow the denali back to their shop and they agreed to pay for the repairs of the transfer case and to correct the mismatch.

This ended much better than I had anticipated. Props to this company for owning up to their mistake and for correcting the problem.

elitecollection

Hi so ive read a few different treads and came a cross this 1 and its the closest to my noise . Just a quick briefing i own a 2002 yukon denali xl and i run it with bel tech lowering springs ,torsen keys and shock relocators
and run 24's nine months out of the year .

I have changed the front diff due to its notoriously known problem but now a new annoying issue presents it self> as i turn in either direction ''like into a driveway and even just making a right turn it sounds like a 4x4 on dry pavement . Before i get to fixing it why did you change your gears after you lowered it ??? thanks EC