Wont shift into 4WD

[hoser]

Hi
I have a 1996 Tahoe 4x4 with the electronic shift for 4WD but it will not shift into 4WD HI or LO.

I followed the instructions in the owners manual but all it will do when I hit the 4WD HI button is the light will flash a bunch of times then stops and goes out, it never goes into 4WD, the 2WD button light always stays on never blinks, same happens when I try to go into 4WD LO range.

Any ideas?

What are the common problems with this type system?

Thanks in advance...

 

[tim@sp]

Most of the time its the encoder motor on the transfer case. IIRC its about $120

Replace that and you should be fine.

Tim

 

[hoser]

Most of the time its the encoder motor on the transfer case. IIRC its about $120

Replace that and you should be fine.

Tim

Is their a test you can perform on it, the service manual I bought (Haynes) is pretty poor...

Thanks

 

[hoser]

Update I just found these


New Venture NV243 PART I
http://www.rsgear.com/articles/2000_01.pdf

New Venture NV243 PART II
http://www.rsgear.com/articles/2000_02.pdf

 

[tim@sp]

I am pretty sure that is what is going on... I have a snap on scanner that Shows if the encoder motor is activating or not... but you can have someone push the button while you are underneith the truck.... you will hear it activate.

If you dont... It might be a switch, but every one i have done it was the encoder motor.

Tim

 

[hoser]

I am pretty sure that is what is going on... I have a snap on scanner that Shows if the encoder motor is activating or not... but you can have someone push the button while you are underneith the truck.... you will hear it activate.

If you dont... It might be a switch, but every one i have done it was the encoder motor.

Tim

Any tricks to changing the encoder motor other than unbolting?

Thanks again

 

[loulblades]

Most of the time its the encoder motor on the transfer case. IIRC its about $120

Replace that and you should be fine.

Tim

When you mention the encoder motor, I guess you are assuming that this does not have the thermal actuator as early build '96 Tahoes had.

 

[hoser]

What oil is suppose to be used in the transfer case I am hearing conflicting info on what to use.

 

[tim@sp]

The automatic transfer case takes:
automatic transfercase fluid (Gm part No. 12378396)

Manual Transfercase takes:
Dextron III

The Front Drive axle Case take:
SAE 80x-90 g15 Gear lube

This info is from All data... I am not sure if there is an aftermarket for this or not.

 

[hoser]

The automatic transfer case takes:
automatic transfercase fluid (Gm part No. 12378396)

Manual Transfercase takes:
Dextron III

The Front Drive axle Case take:
SAE 80x-90 g15 Gear lube

This info is from All data... I am not sure if there is an aftermarket for this or not.

Thanks for the info, anybody know what the GM automatic transfer case fluid is?

 

[Cooligan]

The automatic transfer case takes:
automatic transfercase fluid (Gm part No. 12378396)

Manual Transfercase takes:
Dextron III

The auto transfer case is considered the push-button 4 wheel drive and the manual is the selector on the floor, correct? Forgive my ignorance but I'm new to dealing with transfer cases. Thanks.