2013 Silverado 1500 LT 5.3 electric switch 4wd not working. New truck so don’t know the backstory with the 4wd going out. Electric switch says 4wd works and is on. Put the truck on stands and the front wheels spin free in all modes no engagement of the the diff. Cycles through 4H and 4L and can here the shift motor working when switched between each mode. Front drive line free in 2wd, and engages in 4H and L. Actuator visually inspected and works fine. Fixed leak in the axel tube seal and looked at the fork and clutch, both looked fine. I’m not sure what else to rule out aside from something in the transfer case, which I’m hoping isn’t the case. Any help on other things to take apart or look at first while I have the transfer case drained and half off would be greatly appreciated.

thank you

 

If you put the vehicle in 4wd and the front drive shaft doesn't turn and in 2wd the front drive shaft spins free it sound like the transfer case is working. Any time the 4wd is in any position other than 2wd the front differential should be engaged. You can remove the front diff actuator and use a screw driver to engage the front diff to verify it's operation. Have seen the shim between the stub shaft and right output fall out of position when reassembled. Something to check as you stated the differential was disassembled. Can verify circuits to front differential actuator are ok. It's possible the actuator it self is no good. Hope this helps.

 

Thanks for the help. Turns out the spring that pushes the fork back when the actuator disengages had been damaged and bound up preventing the actuator from being able to push the forks in to engage. With the damaged spring out of the way I can push the fork in again and engage the diff finally

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