04 Gmc Sierra Z71

[marinetodd06]

I just bought a 2004 GMC Sierra Z71 with 67,000 miles and an automatic transmission about 3 weeks ago. Until today, the truck drove perfect. While driving home, on a local road approx. 45 mph, it seemed like the truck jumped out of drive and into neutral. I pulled off on the side of the road and put it in park to try to figure out what the problem was and soon realized that the truck would not go back into drive, gears 3, 2, or 1, or reverse. The truck starts and runs just fine. Any help would be greately appreciated.

[silveradobobby]

I just bought a 2004 GMC Sierra Z71 with 67,000 miles and an automatic transmission about 3 weeks ago. Until today, the truck drove perfect. While driving home, on a local road approx. 45 mph, it seemed like the truck jumped out of drive and into neutral. I pulled off on the side of the road and put it in park to try to figure out what the problem was and soon realized that the truck would not go back into drive, gears 3, 2, or 1, or reverse. The truck starts and runs just fine. Any help would be greately appreciated.

 

 

Sounds like like a broken pump gear or vane gear. Or the low reverse sprag gave away!

[Alljackedup408]

+1 .... or could be the torque converter if its really messed up!

[marinetodd06]

+1 .... or could be the torque converter if its really messed up!

 

I have no idea. The column shifter still shifts as smoothly as ever with no grinding noises and gives the indication of what gear it should be in, but no dice with any of the gears...reverse lights even come on when put into reverse. Another thing that is confusing to me is when put into drive (or any other gear), the idle of the engine drops down as if it's in gear except the truck doesn't give the little "jerk" you feel when the transmission is engaging and when i press on the gas pedal (when in drive, or any of the other gears) the engine rpms increase freely as if the truck were still in park or neutral. No weird noises, knocks, or grinding. All I can hear is the engine rpms increasing. Another thing...I tried engaging the 4wd to see if I could even get the truck to move under its own power. I could hear the t-case engaging in and out of 2hi 4hi and 4lo, also without any weird noises or grinding, but that didn't do anything either...truck still wouldn't move when put into any of the gears.

[Alljackedup408]

It sounds like a hard part has let go... could be the pump.. cause if its messed up.. and cant get fluid pressure to any of the pistons.. you have a no go cause no clutches will be applied. have you checked the fluid color and or smelled it? does it smell burned? and will the truck move at all?? like maybe creep under lots of throttle?

[marinetodd06]

It sounds like a hard part has let go... could be the pump.. cause if its messed up.. and cant get fluid pressure to any of the pistons.. you have a no go cause no clutches will be applied. have you checked the fluid color and or smelled it? does it smell burned? and will the truck move at all?? like maybe creep under lots of throttle?

 

Checked the fluid yesterday on the side of the road. Still looks and smells new. I was talking to a buddy of mine today and he said that he had the same exact problem with his 01 Sierra about a year and a half ago. He told me it turned out to be the pump. As far as getting the truck to move at all with a lot of throttle...nope...won't move.

[Alljackedup408]

yea, have a feeling its time to pull the transmission and to pull the pump outta it.

[marinetodd06]

yea, have a feeling its time to pull the transmission and to pull the pump outta it.

 

So...after a little blood and sweat, got the tranny pulled out and found out that it was indeed that pump that was bad. Replaced it and now my baby is back and driving again. Thanks a lot for your help!

[Alljackedup408]

Good deal man!! glad it worked out for you!

[pennzoil29]

yea, have a feeling its time to pull the transmission and to pull the pump outta it.

 

So...after a little blood and sweat, got the tranny pulled out and found out that it was indeed that pump that was bad. Replaced it and now my baby is back and driving again. Thanks a lot for your help!

 

 

It's alway's a good thing when you're back behind the wheel.

[Alljackedup408]

Indeed it is! Just got the trans back in my big truck.. the stator in the torque converter let go.. so while i had the trans out i went ahead and rebuilt it. Put some goodies in it as well... and tricked the valve body out a bit