4-Wheel Drive problem

nhproxr · June 18, 2004

Got a '98 Yukon and when driving after a few miles the 2-high indicator light goes out on the dash button and the steering gets slightly heavier. Truck doesn't fully engage in 4x4, just feels funny. If you switch it to auto trac or 4-high it positively goes into that gear and the light for that button soon goes out too. What's up?? Just the dash switch or something else?? GM tech told me it is often some module in the t-case that costs like $500!!! Truth to this? Also was told if you remove 4wd fuse and put back in the electronics in the t-case reset themselves and sometimes solve this problem. Did that didn't work. Help, its driving me nuts!!!

GMCTech · June 18, 2004

You're going to have to get some codes read out of it - there should be codes stored with a fault like that.

Yes it could be something as simple as the switch, but it is possible to be the TCCM (Transfer Case Control Module), or it could be the encoder motor or its position sensor.

It sounds like the TCM loses communication with the encoder motor.

After the lights turn off are you able to do anything? Will it change at all aat that point? Does just turning the key off then back on "reset" it, allowing normal operation?

These are some things that would be helpful to know, but most helpful will be any codes pulled.

Hope we can help.

orbitron · June 18, 2004

Replace the switch.

nhproxr · June 18, 2004

When the light goes out like I said the steering gets slightly firmer, but I know 4wd is not fully engaged. Other then that it operates as normal. Even with the light out, if you put it in 4wd or auto trac it switches right over, then you drive for a bit and even that light goes out. Function of the t-case does not seem to be affected at all, just feels slightly funny and I'm worried it may strain the drivetrain on dry pavement.

I have a handheld code reader, but it is picking up no codes. It's just one of those $150 ones from auto zone, but picks up no codes and there are no check engine lights coming on or anything.

Oh yeah when the key is shut off and truck restarted it resets and the indicator light is back on, then goes out after drivning a little.