Will not go into reverse

REARBREED

MEMBER
2001 GMC YUKON
0.6L
V8
4WD
AUTOMATIC
218,000 MILES

I just took out my transmission and put a new one in and it still will not go in reverse, but will go in drive. And that is what it was doing before I put the other one in. Can you help me please? What else can cause that or stop it for going into reverse?

5 Replies

KEN L

MASTER CERTIFIED MECHANIC
47,490 POSTS

Hello,

It sounds like you have a gear range sensor that is not working. Can you tell me if the reverse lights work? There are five fuses that run the system as well. Let's make sure there is power at each of them. Here is a guide to help and the fuse locations with the transmission wiring diagrams so you can see what fuses to check and how the system works:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Check out the diagrams (below). Please let us know what you find.

Cheers, Ken

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Wednesday, October 17th, 2018 AT 10:34 AM

REARBREED

MEMBER
4 POSTS

Yes, the reverse light comes on but it will not move after they change the transmission. I have some flashing lights on the dash they just keep flickering like back and forth to brake and the seat belt light.

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Wednesday, October 17th, 2018 AT 6:18 PM

KEN L

MASTER CERTIFIED MECHANIC
47,490 POSTS

It sounds like you have a bad PCM but we should run the codes to see what comes up.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run down this guide and report back.

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Thursday, October 18th, 2018 AT 9:55 AM

REARBREED

MEMBER
4 POSTS

Hey Ken I checked the fuses and stuff and they're all good I'm now where is the gear range sensor located at

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Monday, October 22nd, 2018 AT 3:40 PM

KEN L

MASTER CERTIFIED MECHANIC
47,490 POSTS

Can you check the ground wires for the transmission harness? It sounds like one is not hooked up.

The gear range sensor is on the left side of the transmission at the shift cable hook up. Here is a diagrams below to help show you.

1. Apply the parking brake.
2. Shift the transmission into neutral.
3. Raise the vehicle. Refer to Vehicle Lifting.
4. Remove the nut securing the transmission control lever to the manual shaft.
5. Remove the transmission control lever from the manual shaft.
6. Disconnect the electrical connectors from the switch.
7. Remove the bolts securing the park/neutral position switch to the transmission.
8. Remove the park/neutral position switch from the manual shaft. If the park/neutral position switch did not slide off the manual shaft, file the outer edge of the manual shaft in order to remove any burrs.

Check out the diagrams (below). Please let us know what happens.

Cheers, Ken

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