Transmission issues

Msb7800

Original poster
Member
Sep 9, 2019
3
Florida
Have a 04trailblazer ls 2wd transmission won't shift ,I replaced the transmission at Xmas time, well going down interstate doing about 85 on cruise and rpms went up and was like I put it in neutral replaced with a used on ,now a week ago it did the exact same thing so I went and purchased another tranny and have it in but wont move, I changed the fluid and filter but still nothing ,says any and all help would be greatly appreciated,could it be an electrical issue ? Thank you in advance for the help
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Hi and welcome.

Are there any codes? If it's electrical, there would be codes and it would still move in limp mode in second gear.

Check to see if the pump is working. It's quite possible that during installation, if the torque converter wasn't in properly before you mated the tranny to the engine, the pump got damaged. It has happened before here.

To check the pump, pull out the driver side cooler line at the radiator, stick a hose on it and put the other end in a bucket. Start the engine. You should have a strong steady flow from it.
 

mrrsm

Lifetime VIP Donor
Supporting Donor
Member
Oct 22, 2015
7,642
Tampa Bay Area
Welcome to GMT Nation...

I know you've probably already investigated this ...but just to eliminate this possibility if you have been Manually Up & Down Shifting the Transmission, take a look directly under the Driver's Side Under Body at the Shift Cable that attaches via a Nylon Grommet to the Shift Armature of the 4L60E Transmission. On occasion, that Cable Grommet Connector can fall off of that Metal Shift Lever and disconnect the In-Cab Shifter Handle from being able to activate the Transmission PRNDL re-positioning.

If you determine that the Cable is hanging down, the Repair is quite simple by getting one of these and Popping out the Old Loose One and Popping in the New One. Please Chock the Wheels Front & Back to prevent the vehicle from rolling over onto you when moving the Lever around during this Installation. Reposition the inside Shift Handle into the Park Position before attempting to Start the SUV:

s-l300.jpg
 

Msb7800

Original poster
Member
Sep 9, 2019
3
Florida
Hi and welcome.

Are there any codes? If it's electrical, there would be codes and it would still move in limp mode in second gear.

Check to see if the pump is working. It's quite possible that during installation, if the torque converter wasn't in properly before you mated the tranny to the engine, the pump got damaged. It has happened before here.

To check the pump, pull out the driver side cooler line at the radiator, stick a hose on it and put the other end in a bucket. Start the engine. You should have a strong steady flow from it.
Thanks mooseman I'll check the pump and see ,is it hard to change the pump or expensive, I just got the transmission and has a warranty know I'll have to drop it to change the pump so , question is would just swapping it out again be quicker and easier.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
I really don't know. Maybe someone with more experience with these can chime in.
 

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