Hey guys, I am trying to help a co-worker with his 02 trooper. It has the TOD system. We are trying to figure out if the 4x4 is working the way it should. In high range we push the "auto 4x4" button and on the TOD display none of the wheels light up but the "auto" light in the center oh it constantly flashes. It turns off when you turn the "auto 4x4" off. If you switch into low range and push the auto 4x4 button the front wheels light up solid on the TOD display but not the rear. Is this the way it is supposed to work? If not what should be showing on the TOD display in High and Low range 4x4? Thanks for any help.

 

The wheel lights not lit and Auto flashing is telling you something is wrong. Either the t-case is not shifting into 4WD mode or, more likely, the vacuum actuator that locks the front axle shafts together in 4WD is not working.

 

Okay, thanks for that. Is there a reason that in low range the front wheels show lit on the TOD display but not the rear? Can we bypass the vacuum actuator and just run a separate vacuum line down from the engine to engage the front axle, (I understand it would need to be switched on and off manually)?

 

IDK why the TOD displays that in 4WD Low, unless maybe its because you're pushing the Auto button while the shifter is in Low. You don't have to do that.

There are 2 vacuum solenoids mounted on a plate on the front axle. One to lock and one to unlock.
You could bypass the suspected bad one.

 

So by shifting the tc shifter into low range that should put the Trooper in 4wd and you don't need to push the auto 4x4 button on the dash?

 

Yes, putting the t-case shifter into Low range also commands the front axle shafts to lock.