allison won't go into 4Xdrive (sometimes)

[DZLHUMMR]

our 03 Hummer H2 has a Duramax LLY and Alison 6 speed auto in it.

We have been having trouble with it not wanting to go into 4WD. we push the dash button and you can here a short elect motor sound but light keeps flashing.

Took it back to Predator Motor sports in Vista, CA who did the conversion.

They charged us $345 to find the problem which they said was a "loose connection @ the "module under the dash" we got it back and it immed. did the same thing. when I called Predator they said: " oh well maybe the module is going bad" "they cost about $300" GRRRRRRRR!

They have been "less than responsive" on the issue. I got up under the dash and "wiggled" some connections and it worked again but soon stopped!!

I'm stumped. ANy ideas? (sorry for the long post)

 

[Darius6t9]

Pull the plug and see if any of the pins are pushed in. If they are, see if you can pull them out to get the proper connection. Might have to clean them also.

 

[DZLHUMMR]

Great! Now if I knew just WHICH Plug to pull I could do just that. There are several "boxes" + multi wire "plugs in that general area (close to the HVAC vent to the right of the steering column??? Thanks

 

[wes06dmax]

Sometime all you have to do is just change the 4wd switch there was a thread on here about this look and see if you can find it and see if it will give you more info:thumb:

 

[DZLHUMMR]

Sometime all you have to do is just change the 4wd switch there was a thread on here about this look and see if you can find it and see if it will give you more info:thumb:

Do you mean the actual switch on the dash?

If so, why would me fooling around with the harness under the dash cause it to work sometimes?

 

[wes06dmax]

Do you mean the actual switch on the dash?

If so, why would me fooling around with the harness under the dash cause it to work sometimes?

Could be just a short in the switch and when you move the harness around it could make something touch together better like I said Im not saying this is your problem but I would check it out and see

 

[hondarider552]

Is your hummer in AZ and is it gold??

 

[DZLHUMMR]

Is your hummer in AZ and is it gold??

No it's black and in So Cal

 

[DZLHUMMR]

NEW INFO!

OK, so I press the 4X4 switch and the light just flashes and no 4WD. then Iget the "service 4WD message on dash. If I then press the reset button on the steering wheel the message goes away (of course) and it goes into 4WD! same thing going OUT of 4WD. Now I am really stumped!

 

[LBZ_Duramax]

If it is the switch itself the light on the switch will not be working. I would say encoder motor sensor. Have someone with a TECHII check and see what the codes are.

 

[DZLHUMMR]

ANyone know a GOOD Durramax/Allison mech. in the San Fernando valley area?

 

[DZLHUMMR]

anyone know a good durramax/allison mech. In the san fernando valley area?

bump

 

[super38834]

This sure sounds like a bad encoder sensor.Not real hard to change either

 

[DZLHUMMR]

This sure sounds like a bad encoder sensor.Not real hard to change either

Ok...Thanks, What is an encoder sensor and WHERE is it?...

 

[DZLHUMMR]

The hardest kind of problem to cure is an intermitent one. today I drove the H2 and tested 4WD 30 times!! Worked perfect every time; in park,drive and neutral. rolling and stopped ???

 

[DZLHUMMR]

Actually I DID do one other thing. I made a talisman out of feathers and beads and blessed it and hung it from the rear view mirror.....Who knows? (smile)

 

[C.C.Reed]

Here is a .pdf I downloaded a while back. Check the switch first. It is not the exact same as your truck but the principle is the same.

View attachment 4WD Switch Repair.pdf


If that doesn't work, it's more than likely the encoder which is located here. Picture is with front drive-shaft and yoke removed.

The gear inside rounds off.

^^^Credit for the pictures goes to mrl112 on Z71TS.