Transfer case will not shift
Mar 27, 2022 | 03:54 PM
#1
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Transfer case will not shift
Hello all,
I seem to but hope not to have a unique issue. My transfer case will no shift (with the encoder motor) in or out of any mode. It has had this issue since I bought it but am now trying to repair. It used to be stuck in 4wd and the 4wd light on the push button would illuminate. When I would push any other button beside auto 4wd, the corresponding light would blink and I could hear a bunch clicks from under the dash. I could also hear the encoder motor whirring and also the front axle actuator. Then it would stop trying to shift and all the push button lights would go out. The truck would then still be stuck in 4wd. I could pull the fuse and the front axle would disengage and I could drive around in quasi 2wd. That is how the truck has been for about a year that I know of.
Now this weekend I put a new encoder motor on and now it’s doing the same thing but in neutral. I manually found neutral with a wrench to line up for the new encoder motor. Installed everything back and all pugs connected. Turn the key and neutral light illuminates. Push any other button and that light starts blinking. Gear selector in neutral and the chorus of clicks and whirring begins then it tries to default select 4wd and that light takes over blinking. Then it’s stops and shuts down. All lights off. Stuck in neutral. I don’t know a lot about these but it almost seem as if the encoder motors were/are not strong enough to induce a shift. Please help me. Thank you
I seem to but hope not to have a unique issue. My transfer case will no shift (with the encoder motor) in or out of any mode. It has had this issue since I bought it but am now trying to repair. It used to be stuck in 4wd and the 4wd light on the push button would illuminate. When I would push any other button beside auto 4wd, the corresponding light would blink and I could hear a bunch clicks from under the dash. I could also hear the encoder motor whirring and also the front axle actuator. Then it would stop trying to shift and all the push button lights would go out. The truck would then still be stuck in 4wd. I could pull the fuse and the front axle would disengage and I could drive around in quasi 2wd. That is how the truck has been for about a year that I know of.
Now this weekend I put a new encoder motor on and now it’s doing the same thing but in neutral. I manually found neutral with a wrench to line up for the new encoder motor. Installed everything back and all pugs connected. Turn the key and neutral light illuminates. Push any other button and that light starts blinking. Gear selector in neutral and the chorus of clicks and whirring begins then it tries to default select 4wd and that light takes over blinking. Then it’s stops and shuts down. All lights off. Stuck in neutral. I don’t know a lot about these but it almost seem as if the encoder motors were/are not strong enough to induce a shift. Please help me. Thank you
Last edited by reubone; Mar 27, 2022 at 04:01 PM.
Mar 27, 2022 | 04:38 PM
#2
The GMT800 4wd switches are common to have bad solder joints, certainly something to look into. The switch pops out of the dash, and the switch pretty much pops apart too
Was the case easy to manipulate with a wrench? You might have a sticky case and the encoder is hitting its current limit
Does the encoder and switch work properly not bolted to the case?
Are you rolling 2-5mph while trying shift between 2hi/4hi?
Are you stopped with trans in N before trying for 4lo?
Will the front axle disengage at the CAD actuator properly?
Assuming you don't have a case that needs service, the 4wd system is pretty easy on the 800s
Was the case easy to manipulate with a wrench? You might have a sticky case and the encoder is hitting its current limit
Does the encoder and switch work properly not bolted to the case?
Are you rolling 2-5mph while trying shift between 2hi/4hi?
Are you stopped with trans in N before trying for 4lo?
Will the front axle disengage at the CAD actuator properly?
Assuming you don't have a case that needs service, the 4wd system is pretty easy on the 800s
Mar 27, 2022 | 07:57 PM
#3
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The GMT800 4wd switches are common to have bad solder joints, certainly something to look into. The switch pops out of the dash, and the switch pretty much pops apart too
Forgot to mention that I replaced the switch.
Was the case easy to manipulate with a wrench?
I was able to move it without much effort.
You might have a sticky case and the encoder is hitting its current limit
This could be
Does the encoder and switch work properly not bolted to the case?
I was told doing this would cause permant damage to the unit.
Are you rolling 2-5mph while trying shift between 2hi/4hi?
Before replacement yes. After replacement no the transfer case is stuck in neutral
Are you stopped with trans in N before trying for 4lo?
yes
Will the front axle disengage at the CAD actuator properly?
yes
Assuming you don't have a case that needs service, the 4wd system is pretty easy on the 800s
Forgot to mention that I replaced the switch.
Was the case easy to manipulate with a wrench?
I was able to move it without much effort.
You might have a sticky case and the encoder is hitting its current limit
This could be
Does the encoder and switch work properly not bolted to the case?
I was told doing this would cause permant damage to the unit.
Are you rolling 2-5mph while trying shift between 2hi/4hi?
Before replacement yes. After replacement no the transfer case is stuck in neutral
Are you stopped with trans in N before trying for 4lo?
yes
Will the front axle disengage at the CAD actuator properly?
yes
Assuming you don't have a case that needs service, the 4wd system is pretty easy on the 800s
Mar 27, 2022 | 08:06 PM
#4
If you're worried about damaging the new encoder, do you have the old to try the "in the air" test?
I don't think it damages anything, when we do the cheater 241 swap, the encoder gets zip-tied to the frame and no one I have read about or met has ever said it has stopped working for them that way
I don't think it damages anything, when we do the cheater 241 swap, the encoder gets zip-tied to the frame and no one I have read about or met has ever said it has stopped working for them that way
Mar 28, 2022 | 06:30 AM
#5
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If you're worried about damaging the new encoder, do you have the old to try the "in the air" test?
Yes, in fact I do have to old one to test!
I don't think it damages anything, when we do the cheater 241 swap, the encoder gets zip-tied to the frame and no one I have read about or met has ever said it has stopped working for them that way
Yes, in fact I do have to old one to test!
I don't think it damages anything, when we do the cheater 241 swap, the encoder gets zip-tied to the frame and no one I have read about or met has ever said it has stopped working for them that way
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Mar 29, 2022 | 10:35 AM
#8
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This guy is sharp haha it was in fact the old one but check this out. I cut the plug off to get to the wiring. Once I figured out the correct polarity of the lock out solenoid, I could get the encoder to rotate back and forth. So that led me to the truck wiring where I found the ground(Tan color) wire for the lockout solenoid had a break in it. So I patched the wire and presto! Now I get all excited and move around in the drive way switching in and out of 4wd…..then it stops working and I am again stuck in 4wd. Same issues all over again. So I guess I’ll get my tester back out and find another break in the wiring. I think a mouse live in this truck for a while looking at the wiring. Sure could have saved a lot of money testing the wiring first. Oh well. Thanx guys