hardly worth mentioning
Crashes / Fires:
0 / 0
Injuries / Deaths:
0 / 0
Average Mileage:
52,756 miles

About These NHTSA Complaints:

This data is from the NHTSA — the US gov't agency tasked with vehicle safety. Complaints are spread across multiple & redundant categories, & are not organized by problem.

So how do you find out what problems are occurring? For this NHTSA complaint data, the only way is to read through the comments below. Any duplicates or errors? It's not us.

2006 GMC Sierra 2500 transmission problems

transmission problem

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2006 GMC Sierra 2500 Owner Comments

problem #5

Mar 282010

Sierra 2500

  • 49,341 miles


2006 GMC diesel with allison transmission...lines to transmission cooler leaking. It is a fire hazard...from what I read on the internet it has been a problem with all the transmission lines installed on this truck

- Northfield, MN, USA

problem #4

Mar 042009

Sierra 2500

  • 32,000 miles
I have a 2006 GMC Sierra 2500 with the lbz duramax and allison transmission. Two of the transmission coolant lines began leaking transmission fluid at the crimp ends in March of 2009. The truck only had 32,000 miles, but was 3 months beyond the 36 month warranty period. Service under warranty was denied. An on-line search reveals several others have complained about this issue and that the dealer installed oem replacement lines are no better (developing leaks soon after replacement), yet no tsb or corrective action has been issued by GM. Leaking transmission fluid is a fire and environmental hazard. The leaks are getting worse.

- Las Vegas, NV, USA

problem #3

Nov 302007

Sierra 2500 8-cyl

  • 22,800 miles
The contact owns a 2006 GMC Sierra 2500. The fly wheel, which runs with the transmission and helps change gears has had to be replaced three times within two years. While driving approximately 10 mph during the first failure, there was a loud clicking noise and it became louder over time. The dealer stated the vehicle was operating normally. A few weeks later, the noise was much louder; however, a different dealer 2 hours away diagnosed the vehicle and stated that the fly wheel failed. After being repaired 24,000 miles and a year later, the failure recurred. The fly wheel was replaced again and lasted 5 months before it failed. The power steering shaft also needed to be replaced due to it being worn out and failed again nine months later. The failure mileage was 22,800 and the current mileage was 55,000. Updated 06/08/09 the power steering gear was leaking due to leaking gear assembly, the HVAC blower was inoperative, the flywheel was cracked. The dealer replaced the stripped and broken exhaust studs. Updated 06/18/09.

- Homosassa, FL, USA

problem #2

Jan 112009

Sierra 2500

  • 58,260 miles
I am the shop foreman for a construction company in Alaska. I dropped off a 2006 GMC 2500 pickup last week to the dealer to have a leak looked at. I got a call back from them saying my torque converter was blown. They said GMC is having problems with the allison transmission at cold temps (campaign # 07293) I had this truck in at 25000 miles to be re-programmed and again at 49000 miles. Now, at 58,000 miles the torque converter is blown and after arguing with GMC, they will not warranty the work, they want me to pay half of the 3200. I drove up in out company's brand new '08 GMC 3500, had the dealers mechanic look at it. He sniffed the tranny dipstick, grimmanced, and said that it too was blown. At 4120 miles, another blown torque converter. The service manager said 17 trucks so far in fairbanks Alaska have suffered similar fates, due to this manufacturer error. I am livid, to say the least! GMC needs to be held accountable for this, and owners need to be contacted and told that there is a problem! there is a safety angle as well, according to the mechanic--at a stop light, the torque converter went out, locked up, and pushed the vehicle through the light!

- Fairbanks, AK, USA

problem #1

Sep 182008

Sierra 2500

  • 101,380 miles
I own a 2006 GMC 2500hd duramax/allison crew cab. I took ownership in Feb of 2007 with 32K miles. Transmission lines were leaking at that time. Dealer replaced the lines under warranty. Now at 100K miles and same "new" lines are leaking once again. This is a flammable fluid and constitutes a potential fire hazard.

- Barrie, Ontario, Canada, 00, USA

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