27th Jan 2007, 14:24

I own a 2003 Z71 Tahoe and have the same problem many others have with the Service 4 Wheel Drive message and the lights on the selector switch going on and off. I also have had the vehicle twice shift on its own from 2HI to 4LO. Thankfully both times were at relatively low speeds (25 to 35 mph) - I hope it never happens at 60 mph. After much struggling with the selector switches, I have been able to return to 2HI. I've seen many messages on other boards with the same problem for 1999 to 2005 Tahoes, Sierras, Avalanches, etc. I replaced the selector switch myself ($65 for part at local dealer), but problem returned several weeks later. I had the dealer take a look and they were not able to download a trouble code. GM's PI recommended with no code replacement of the Encoder Motor at almost $900, but the Technician said there was no guarantee that that would fix it. Obviously, I did not authorize the repair. I have seen many suggestions on other boards (reprogram the TCCM, Replace the wiring harness, replace the selector switch, replace the Encoder Motor or Sensor, pull the 4wd fuse and only use 2wd, etc.) but no one (including GM) has come up with a sure fire solution as most of the posters have had the problems return. My question (s) are, does anyone have a sure fire fix, and if not, why has GM continued to manufacture and sell these vehicles equipped with the electronic select shift year after year with a known problem and no known solution. Help, ANYONE, I'm at my wit's end.

6th Feb 2007, 10:58

Four Wheel Drive Train Problems - I have a 1999 GMC K-1500 with similar 4WD problems. With only 50,300 miles (1885 hours), the 4WD will not engage. The Transfer case oil has metal particles in it and shows signs of burned oil. It appears related to the front axle not turning freely. I am currently tearing down the front axle which is the only way to even investigate the axle problem (Standard labor time is 6.5 hours for this task alone) All maintenance has been performed to dealer specs. The 4WD has probably been used less than 8-12 hours in the 8 years I have owned it.

21st Mar 2007, 22:49

My 2000 G.M.C. has an array of "problems" (oddly enough I do love it anyway). problems include: warning lights; service 4x4,shows the engine symbol. Dealer could not fix with downloads, but said problem was gone. Once in a while the "cruise " will shut off while going down the hwy. and at the same time one cannot shut the heat adjustment off. You can turn it down, but still roasts you. Does fix itself when you shut it off. Currently when start cold and attempt to go quickly it has no power and will not shift till 3500 r.p.m.

I have spent $850.00 trying to get problem fixed to no avail.

Any ideas other than selling?

5th Jun 2007, 09:14

Transfer-case failed on my 2001 GMC 2500 SLT at 100075 last week 5-30-07. Sudden lost of fluid, hole in tranfer-case located at 1 o'c passenger side about the size of a tooth pick. Truck still in Knoxville awaiting parts?? Sure would like GMC to step-up to the plate on this. Note, all fluids changed by OEM at 78,000 miles with no issues. Is there an avenue for restitution through GMC or do we need to sue?

3rd Aug 2007, 16:15

I have a '99 Chevy 1500 and the rear end blew up. Since I got it back, when I put it in 'Drive' nothing happens. I have to start out in 1 and switch it to drive at about 20 mph to go anywhere. The front driveline is moving and its making a weird clanking noise when I shift. I think it could be the fluid. Is my transmission or transfer case going out?

20th Aug 2007, 15:59

I own a 2004 2500 Duramax. I recently had to replace the T Case because of a pin hole. I see that this is not an isolated problem. I am just over my extended warranty and had to pay $1,000 for the fix. I would like to know if anyone has heard if there is a recall or any other type of compensation available.

1st Sep 2007, 11:51

8/31/2007.

I noticed the underside of my truck was saturated with fluid that looked like transmission fluid. The dealer said the seals needed replacing. The next day I had fluid dripping from the transfer case. After several more hours at the dealer it turned out to be a pin hole in the transfer case on the passenger side. Dealer says it's most likely a design flaw from GMC. It a 2001 3500 with 137K. Has GMC taken responsibility for this?

20th Sep 2007, 10:02

I have a 2001 Silverado 2500 HD w/58,000 miles on it. I just dropped it off to get the transfer case looked at because it is leaking. I found out that a pin hole is the cause of the leak that was created by the vibration of the oil pump. This Sounds like a flaw in the GM design. Any recalls?

21st Sep 2007, 17:46

I own a 2000 GMC 2500HD 4X4 that currently has 159000 miles. The transfer case pin hole thing just happened. The underside of the truck is now undercoated with the fluid. Self tapping screw, JB weld, and some brake cleaner and all is good.

As for other issues, the 4X4 panel has been out for about 35K miles. Being in Michigan without 4X4 is fun. Reminds me of driving my 1974 GMC 2 wheel drive when I was 17 years old.

Drivers side hub assembly twice passenger side once. Under warranty for both the 1st time, then $450 parts & labor the 2nd time at 120K miles.

Both window regulators around 150K miles. $75 each side plus my own labor.

Trans gasket and fluid at 125K miles just because.

Broken hold release latch because I push my foot near it while off road; $28 and my time.

New fuel pump in tank at 155K miles at $435 plus my own time again.

2007 wheels and tires off eBay for $736 since my old wheel have rust bonded to them.

Brakes, brakes, brakes. Got to love those damn guide pins. Slotted and cross drilled rotors with matching pads off eBay for $425. Makes the truck stop faster than anything other than a sportscar.

Hated this truck over my 93 GMC 2500 4X4, but it has served me well. For those that are spending more time complaining than fixing, I am truly sorry for your woe's. As for me, I'm looking to go with the 2500 HD 4X4 with Duramax and Allison for the next replacement.

2nd Oct 2007, 19:54

I bought my 2004 Sierra Z71 4x4 Crew Cab last Tuesday, Friday the Auto transfer case switch went out and "service 4wd" displayed on the message center. After 2 scans and 150 bucks later they tell me 100% it's the TCCM (transfer case control module) Fixed 3 hours later and $800 and change. Did I buy the thing in between the TCCM acting up or did it really go right after I bought it. What is going wrong with these modules, and can they be fixed when they die? Is it the location it's in, vibration, heat, moisture, what.. If mine goes again I will lose it. Very happy with the truck otherwise, great ride, lots of room for kids.