'04 GMC Jimmy 4x4 Service Light Problem

[IROCZer]

Hey guys,
Like the title says, I got an 04 Jimmy, Problem is the "Service 4x4 drive" light.

The dash service light (idiot light) comes on like everyday on ym way home from work, when I cross the exact same rail road track... I've thought about taking a new rout home... but that's only a temp fix as to why it comes on haha. But basically, when ever I hit a bump or rail tracks the light comes serice light comes on.

When I shut the truck off, get gas or whatever, come back out, restart the truck... the service light is off.

When the service light is on, I cant shift it into 4x4, 4x4 hi light flashes usually then goes back to solid 2x4 light, and other times it does inidcate that you are in 4x4, but you're not.

Any thoughts/ideas?

[CVX20SPRINT]

Just a guess,but I would bet you have a wire rubbed through at the back of the engine/transfercase area.You really need to get a code reader or a scan tool hooked up to it and read the stored history codes to send you in the right direction.Or join a GM Truck forum and seach the PSB's(Product Service Bulletin's)for your issues.