lost 4WD

[matuva]

on a 1996 K1500 with the 6.5l engine.

I'm not sure, but it seems the mechanic did something wrong on the front axle when replacing the output shaft seal of the front axle, passenger side.

To replace, the seal, he just pulled out the shaft, replaced worn seal, and then replace/push inside the output shaft till it gets back in place.

Did he the things right or did he made some mistake? Is it possible something felt inside (e.g. fork, shims, etc....) or no way it can happen?

 

[ak diesel driver]

checked the TLA?

 

[great white]

Sounds like he did the job the right way as thats how the axles come out.

There's a "clip" on the axle end that pops in and out when you use a slide hammer to pull the axle shaft out of the diff.

It's possible your actuator took a dump (coincidence) or it might be disconnected ( although shouldn't be, not necessary to do the job).

Do you have the lever or pushbutton transfer case?

Lots more can be broken if it's pushbutton....

 

[matuva]

TLA?

 

[matuva]

Yup Great White. i was looking at an exploded view of a front end, and it seems to me there's no way anything can drop down, but wasn't sure....

 

[great white]

TLA?

Thermo linear actuator.

That's the actuator that engages the front diff. It works by heating up wax pellet that pushes out a rod which engages the diff.

Notorious for failing often and without notice.

Later years went to a stepper motor. Much more reliable. You used to be able to get a retrofit kit to replace
The tla with the newer design from gm parts. Not cheap though...

 

[matuva]

This truck gets a stepper motor upgrade. I believe something has failed elsewhere.
We will try a new stepper motor.

As long as I know now that he did pull out and put back the shaft the right way, we will investigate other paths

 

[bison]

I rebuild a front axle some years ago.
I think you have to remove the steel axle housing from the pumpkin on the pass side,i don't think one can just pull the shaft on that side.(its been awhile so i ain't sure)
That side shaft is way longer than the dr side one,and has the shift mechanisme on it as as well.