I work for this guy and the work truck is a 1998 T100 3.4, 5 speed 4x4, with 144,xxx on the clock , its also extended cab. Well every time the truck is put in reverse the 4WD light lights up on the cluster and when you put it back in 1st gear the light turns off and you can hear the Tcase disengage why is that? is it because the linkage or what?

 

Might be an electrical short and it might be causing the front differential to engage.

ETA: I mean an electrical short in your reverse light wires. The are in the same harness as the wire that tells the front diffy to engage.

 

Rogers that will give me some where to start my search , thank you very much

 

Yea I would look for a short between something that gets engaged when you put the tranny into reverse (the back up lights perhaps?) and the 4WD wiring.

 

I'm a newbie on here and I have a 94 T100 and reverse is how I get it out of 4wheel. But you have to take it about 100 ft till it turns off. so if I were to shift into 4 wheel and drive forward about 100ft my 4x4 is on, then if I stop shift it into 2wheel then drive backwards 100ft it's off. thats what the dealer taught me after not being able to get it out of 4wheel. But mine has the auto locking hubs. not sure how the 98 is. if it has auto locking hubs I would start with engaging your 4wheel and disengaging it the way stated above. I would guess it can't hurt.