M1008 Pops out of 4 wheel drive

[DawGoneIt]

We have two M1008's at the fish hatchery where I work, one is our feed truck, the other set up as a plow truck. The plow truck of late has been popping out of 4 wheel drive, both in 4 low and 4 high. I looked over the TM in the site for this truck, an am thinking linkage problem? Anyone out there have a similar issue with a M1008 that does this?

The truck did have a long winter and was heavily used in 4 wheel drive to keep roads and the 22% grade to the facility open. appreciate any suggestions to help us keep our beast running.

 

[True Knight]

I had the same problem with mine. The issue is the shift fork in the transfer case. The fork has two nylon tabs that are the wear surface. When these tabs wear away the transfer case will pop out of gear. I had the t-case rebuilt when I installed the 4L80E transmission and the nylon tabs were completely gone and the fork itself was worn down approx 1/16". The fork was about $60-80. That was about a year and a half ago now, and no problems with it popping out of gear anymore.

 

[DawGoneIt]

Your M1028 came with a 4L80E tranny? 208 T-case? We popped the boot off of the shifter to look at the linkage...looked like the backing nut came loose, so the hatchery mechanic tightened up. We will have to look into the shift for though. This truck has had a lot of use the past two years on plow duty. Thanks for the reply, I appreciate it. will check out our YourTube action too

 

[True Knight]

Sorry, I should have clarified a bit more. Ha ha. It came with the TH400 and the 208 transfer case, and I had the problem with it slipping out of 4wd before I swapped out the TH400 with the 4L80E. When I was doing the swap is when I had the 208 t-case rebuilt.