M1008 tranny wont engage when shifting into 4-high

[DawGoneIt]

Hi all,
Our M1008 plow truck wont engage in drive when put into 4 wheel drive. Tested this with wheel hubs unlocked. Looking through TM right now, but is this a switch issue? Happen to anyone out there? Mucho appreciated if someone can tell me how easy this is to fix.
DawGoneIt

 

[Rmtaunton]

First unlock hubs , put in 4 and check to see if drive shaft moves .

If not put back in 2 wheel drive and lock hubs , check to see if drive shaft moves .

Probably a cruddy or broken hub easy fix,

 

[Drock]

Have you tried it with the wheel hubs (Locked?). Have you checked the linkedge and the fluid levels of the trans & transfer case?

 

[Skinny]

Any chance the linkage is improperly adjusted and the tcase is going into neutral?

2wd to 4wd simply engages the front output, rear output always remains connected.

 

[DawGoneIt]

locked hubs and tried to drive in 2 wheel and nuthin, no go. Hubs yeah?

 

[porkysplace]

View attachment 534523Hi all,
Our M1008 plow truck wont engage in drive when put into 4 wheel drive. Tested this with wheel hubs unlocked. Looking through TM right now, but is this a switch issue? Happen to anyone out there? Mucho appreciated if someone can tell me how easy this is to fix.
DawGoneIt

The switch only works the idiot light on the dash , either linkage out of adjustment or bad transfer case . The truck should still move if the hub locks are not engaging . Does the truck move in 2 wheel drive ?

 

[DawGoneIt]

I put the truck up on stands. Locked the hubs, put in 4WD, put in drive and nothing - no front shaft turning at all, or rear shaft for that matter. Hubs unlocked in 2WD, rear shaft spins fine in drive. 4WD shifter linkage looks ok under there. the Big Ah Ha moment was when employee who reported problem said smoke was coming from the front differential (just got that bit of news). front pumpkin dry when checked, lotsa glitter. Sound like a seized front diff?

 

[Skinny]

That would definately be plausible. Regardless of the hubs position, if the front diff is seized and you are in 4wd nothing is going to move. That is more likely with what you found than the tcase being so far out of adjustement and going into Neutral.