[jimiv]

I have problem with my 4x4 96 burb. When I push the 4x4 button it always engages ok but lately sometimes it won't disengage right away, sometimes it even take the next day.
When I push the 2 hi button the light just flashes and it will not kick back to 2 hi and stays locked into 4 hi and won't even go into 4 low.
I've read alot about the actuator not engaging the 4 wheel drive but I didn't know if this is the same problem or not.



Thanks, Jimi V., Illinois

 

[TrailLeadr]

RE: 96 gmc suburban 4x4 disengagement problems

Usually the actuator fails to engage. sometimes they do get stuck "on", but it's rare.
It's still a place to start.
The next time it happens, disconnect the actuator, then grab a large adjustable wrench, or channel lock, and unscrew the unit from the front axle. If it's failing while engaged, as it is unscrewed it should pop out when fully un-threaded, and you will also see the plunger fully extended.

Once it's out, and unplugged, if it's extended feel the unit, especially around the rubber boot. If it feels warm to the touch, then you may have a short, or the control unit is failing. If it's cold, and extended, that it is getting stuck, and it should be replaced.

this is something you'd probably want to do, either after the vehicle has been sitting, or before you drive it. So you're not mistaking the warmth from friction of the drivetrain, instead of the heater element in the actuator.

Keep us posted on what you find out, and good luck.

 

[jimiv]

How does the 4x4 system work? Is the transfer case always on and after you hit the button it engages the front axels? What is the control unit, the actuator or something else in the system?
It seems like it only sticks on when i'm in snow and spining or stuck in the drive and then need it.
If i'm driving I can usually kick it on and off as needed.

I'm in the midwest and we just got hit with a bad snowstorm that pretty much shut Peoria down far a day so I guess i'm lucky it at least kicks in unlike others.

My wife drove it today and told me that it went back into 2 hi and she was able to turn it on and off a few times as needed.
Last night when I pulled in the drive in 2 hi I got stuck so I kicked it in 4hi and got up the drive as usual but then thats when it stuck on until she drove it today for while.

Thanks, Jimi V

 

[TrailLeadr]

Are you running a spare tire right now? Some vehicles come with a spare that is slightly smaller than the stock tire. I had a '01 ranger that came with 265's, and the spare was a 245. Of course when I needed the spare, was in the winter, and since the tire size was different the rotation was different, which would cause the gears to bind, and not disengage.

Same principle applies to a tire that has low air pressure. It will rotate as though it is a smaller tire, and bind the gears.

I'm not sure if the control module is separate from the computer. I think it is, but I'm sure someone can correct me if need be. As far as the Actuator, or TLA (thermal linear actuator) that is located on the front axle on the passenger side.
Jack up your rig put it on jack stands, and then slide yourself under until you're below the front axle, near the passenger side. Then look for the TLA. Use the following pics to identify it.

one last thing. Are you trying to disengage the 4hi after it's in park? If your drive is a steep incline, and the tranny is in park, you're not going to get it to disengage until you get the tension off the gears. You'd be best to disengage while in neutral, then put it in Park. If you don't already do that.

 

[jimiv]

Actually all of the tires are smaller than the stock ones should be, they were like that when I bought it and they were in good shape so I haven't bought new ones yet.

 

[TrailLeadr]

Well, if they're all the same size it won't make much difference. It's when you have one that's is either a size smaller, or larger than the rest, it places a bind on the gears while in 4wheel.