2003 Sierra 4wd wont engage

[Goolee88]

I recently bought an 03 Sierra from a friend and was familiar with the truck. 4wd was spotty engaging and disengaging at times. I thought it was actuator but actuator is working fine. where should I look next? First post -- appreciate any help u guys can offer.

[gmtech4]

ummmmm ,push button or manual t- case ????

[Goolee88]

Manual shift on the floor. TC will go into low but still no 4wd. 4wd indicator on but not working. and as mentioned actuator extends and retracts

[gmtech4]

wheels off the ground engine off in 4wd ,,,

 

,check frt driveshaft its engaged ...

 

remove actuator and push in the fork to lock the diff and see if its locked as a helper turns the pinion (input)

 

verify the same with the actuator in and in 4wd

 

remove frt drivehshaft for above ,,,

 

take it in to a shop if uncomfortable doing above ,,,

 

was a right front axle seal recently done ???

[Goolee88]

will get this checked out over next couple days and let u know what I find.