Ongoing issue for years.

Started out it would just pop out occasionally under stress. Then more and more, and now all it will do is maybe snag a gear or two after shifting before it starts just clicking.

I've been up and down the vacuum system it seems to be good. Replaced the actuator because it wouldn't hold vacuum long with a pump but seemed to hold fine on the truck. New one does hold much much better but I still had a leak that could have been the tubing setup I had.

I had the axle off and inspected the plastic tabs on the shift fork. They looked to be in great shape. I put the axle stub in with the locking gear and worked the fork back and forth and could see it all seemed to work as intended. I have a replacement, Dorman 600-300 on hand.

Could it be that the fork is bent somehow? Or something else is off so that it will not engage the gear properly? The axle and gear splines looked perfect to me.

Thanks, I really would like to get this working again.

 

I don't know if this will help. You may know all of this but this is a good video that explains how to troubleshoot the system.

 

The Actuator slides a splined collar to connect both axle haves inside the passenger side housing.
If the splines are chewed up, it may not engage fully or will not hold position.
Good luck.