1998 3/4 ton 4wd electric shift stuck in 4wd

[imiceman44]

Anyone know of a trick to disengage it?
I am getting ready to go on a camping trip and will be on pavement a 150 miles, I don't think it will last that long in 4wd.
I tried taking out the driveshaft but I need to drop the exhaust to get it out.

 

[cheavyk10]

Did you try pulling the fuse for the TCCM? Leave it out for 5 minutes and put it back in. Used to work on my S10 before I got a new encoder motor.

 

[imiceman44]

Did you try pulling the fuse for the TCCM? Leave it out for 5 minutes and put it back in. Used to work on my S10 before I got a new encoder motor.

I read about unhooking the battery and I did.
Didn't help.
I will see if that helps

 

[Blue85]

Is this an axle disconnect like the early 90's or just a transfer case shift like the 2000's? Either way, I would try removing the actuator and moving the linkage manually. The transfer case shifters are purely external. You can remove the actuator and rotate the selector shaft with channel locks.

Sorry, you probably already took your trip, but threads need resolution!

 

[imiceman44]

Is this an axle disconnect like the early 90's or just a transfer case shift like the 2000's? Either way, I would try removing the actuator and moving the linkage manually. The transfer case shifters are purely external. You can remove the actuator and rotate the selector shaft with channel locks.

Sorry, you probably already took your trip, but threads need resolution!

Yeah thanks for commenting.
I did take the trip and I didn't have trouble with the 4wd but it feels like I have a transmission problem.
I will try and remove the actuator.
The axle does have something that also automatically engages the 4wd when the tcase sends power to the front.
I am looking into the aftermarket electric actuator vs the original heated element

 

[cheavyk10]

Yeah thanks for commenting.
I did take the trip and I didn't have trouble with the 4wd but it feels like I have a transmission problem.
I will try and remove the actuator.
The axle does have something that also automatically engages the 4wd when the tcase sends power to the front.
I am looking into the aftermarket electric actuator vs the original heated element

Don't forget about the manual version of the front axle disconnect, for some no brainer action.

Chevy/GMC K-Series 4WD Axel Engagement Actuator Bypass | 4x4 Posi-Lok

4WD Axel Engagement Thermal Linear Actuator Bypass for the 1988-1998 Chevrolet/GMC K Series Suburban, Tahoe, Yukon 6 Lug and 8 Lug 4WD

4x4posi-lok.com

 

[76zimmer]

My 99 did the same thing. It was the transfer case mounted encoder motor.

 

[imiceman44]

My 99 did the same thing. It was the transfer case mounted encoder motor.

Yeah.
I figured, so I have a manual shift tcase ready to go in.
But I am also ordering the 4x4 posi loc cable shifter, it will even allow me to have 2wd low, which can't happen with any other actuator

 

[Blue85]

I am looking into the aftermarket electric actuator vs the original heated element

Sorry, I skipped over GMT400's entirely, but isn't the thermal actuator pretty early 90's and soon replaced?

When my mid 2000's lost the transfer case actuator, it was just the sensor and the failure mode was random shifting to neutral on the road. It drove fine in 4x4Auto until I replaced the sensor. That's still working with the 315,000 mile T-case today.

 

[imiceman44]

Sorry, I skipped over GMT400's entirely, but isn't the thermal actuator pretty early 90's and soon replaced?

When my mid 2000's lost the transfer case actuator, it was just the sensor and the failure mode was random shifting to neutral on the road. It drove fine in 4x4Auto until I replaced the sensor. That's still working with the 315,000 mile T-case today.

The 98 I found out is the last year, then they went vacuum which also has it problems apparently.
Nothing better than mechanical positive engagement