14 problems related to automatic transmission have been reported for the 1999 GMC Sierra. The most recently reported issues are listed below.
1999 GMC Sierra 1500. While driving the truck for about 45 minutes to an hour and if stopping at a stop sign or red light the truck will not shift from first gear to second gear properly. Once the truck does shift it is a very hard shift, and if on wet or slippery surfaces the truck will squall the tire. This started around 60, 000 miles. This does not happen every time, it is hit or miss. While pulling across three lanes of traffic the truck shifted properly and was almost hit by on coming cars. Took vehicle to the dealership, and they said it was the transmission. It was a common problem with GMC trucks. There is a kit that is made to fix this problem, but transmission must be replaced and the repair cost is between $700 - $1,800. This happens 4 to 5 times a week.
Transmission hesitates badly to shift 2-3, when cold out.
GMC Sierra has been in shop to many times to keep track of. Truck also has a problem with sticky throttle body which has been dangerous. GMC gave extended warranty in 2000 bacause of problems also issued customer appreciation certificate if I wanted to buy new gm product. Service manager told me to cut my losses and but a new one. GMC will not do a thing for me. Contacted nys attn. General about problems. GMC now has their legal core calling me at home . I have asked them to buy vehicle back research the parts and assembly to protect other owners. GMC says sorry . I asked them how they could warranty rust thru for 100,000 but could not protect abs from corrosion, GMC response was hey you live in new york state. And they are under no financial obligation what so ever.
Abs system fails on panic stops. Suddenly applied pedal presseur locks brake pedal and provides little or no braking for approximately 1 second. I have been told by the dealership's service department that this is typical of all abs and that I need to train myself not to jam the brakes in an emergency. Vehicle was in shop in Dec. 1999 for transmission repair and brakes were supposed to be checked. No check was noted on repair order, but service manager assured me that the mechanic had test driven the vehicle and it was ok. This problem seems to be a result of abs pump overreacting to suddenly applied pedal pressure and locking the pedal with back pressure before braking actually starts. I feel that the brakes should at least chirp the tires first. Currently vehicle is under repair from accident, but it will be taken to another dealership upon completion of this repair.
Periodically transmission would skip a gear, causing engine to overrise. Please provide addt'nl information.
I complained to GMC directly about abs failure and reported it to atty. Gen of nys. I was told its normal wear in states with salt, funny that the paint is good to this day.
When accelerating fast, must let off of throttle so transmission will shift from 1-2, and 3-4 gears. All fluid and filter were changed, problem not fixed.
When attempting to pass another vehicle on an incline at speeds of 55mph to 65mph the transmission shifts into second gear and revs the engine up to 4500 rpms and doesn't increase the speed because it is running at its peak speed in second gear causing me to have to let up on the accelerator and try to get back behind the vehicle I was trying to pass. This same downshifting also occurs when using the cruise control. The dealer did not want to test drive the vehicle on a similarly inclined road to duplicate the problem because he didn't have another vehicle like mine to compare it to. The defect in this transmission could easily put me in a head accident situation and needs to be addressed immediately.
While driving about 25 mph with an automatic transmission gear won't shift between speeds.
No summary.
Transmission - harsh upshift 2-3 & 3-4, been at dealers 3 times to no avail.
No summary listed for above vehicle.
Truck jammed on brakes and shifted into reverse with no warning due to the ecm (brain) malfunctioning. Please describe details.
Truck was drove about 300 miles at highway speed , shut off for 1 hour and drove thru town , stopped at a red light ,proceeded to take off when light turned green, engine reved up but the truck just sat there and did not move. ,I verified truck was in drive snd shifted thru the gears d,3,2,1,2,3,d,n,r,p,r,n ,d engine reved but truck would not move. I turned off engine and restarted ,put it in gear engine reved then the truck started to move as if everything was normal. Truck now has 13k miles and the problem has not repeated,bet I have heard of several other 1999 & 2000 chevy and GMC trucks with the same problem. I beleve this could be a serious defect that could cause injury to occupants or others.