Upgrading an M211

[wilber]

Has anyone ever modified a 211 or 135 by upgrading the drivetrain to rockwells, multifuel, 5 speed and an airshift T-case?

I have a 211 that I love the look of. I don't want to mess with the 302, the auto or the sprag T-case. If I could find a donor M-35 with a shot body I was thinking about making the swap of the entire drive train.

 

[drgreg]

I think your engine would be between the seats.

 

[wilber]

I was afraid of that. thanks for the reply.

 

[Travis89xj]

I an interested to know also. I was thinking of doing the same to my 135 but I haven't picked it up yet to make measurement and what not. Chances are I will let the gas motor everyone on here says they are fun to drive.

 

[wilber]

My 211 eingine runs fine but it has a vibration in the transmission that worries me. It shifts fine but I worry about the reliability. I'm not into restoration, more into functionality.

Last winter I took it out in the snow and ice and didn't like the way the front axle grabbed when idling down. It seemed that when I slowed to take a corner I lost traction in the front. I also have a 35 A2 with an air lock T case and didn't notice the same problem. I assumed it was just the way the sprag T case worked. That got me to thinking about an airlock. Unfortunately with this axle setup you have two rear driveshafts, so if you change the T-case you have to change to Rockwells.

I may still look at the change, but add a big block Chevy from an old dump truck I have.

 

[armytruck63]

Wilber,
The problem you describe might be due to the fact that the M211 has a sprag clutch for front axle engagement. You don't have to shift the front axle in and out to get six wheel drive. When the rear driveshafts spin faster that the front driveshaft, such as when trying to start moving on ice, the sprag clutch engages the front driveshaft and axle. There are two sprag clutches, one for forward travel and one for reverse.

The advantage of this system is automatic engagement of the front axle. The disadvantage is unexpected disengagement of the front axle. For example, if you try to drive down a steep slippery hill in a forward gear using engine compression to hold you back, only your rear axles will be engaged.

I think this may be the cause of a loss of front axle traction when slowing down to take a turn.

 

[wilber]

ArmyTruck63,
I think you are right on the money. Thanks for the info.

 

[armytruck63]

Glad to help. I have a sweet spot for M211's. When I was 10, an M211 was the first military vehicle I ever rode in. I've been hooked ever since, though I don't own an M211 (yet).

 

[colin455]

I was told that the sprag was 6x6 in forward and 4x4(rears) in reverse. Can't vouch for it though. Not yet anyway. Hopefully soon. Will keep apprised.

 

[topo]

The sprag is used for forward only . for reverse the transfer case the lower shift rail is pulled out to lock it in 6x6 but with wear the linkage needs to pull it out more then the mechanical linkage will let it move . it is like it needs to be pulled out 2 inches but the linkage will only pull it out 1 1/2 inches .

 

[Travis89xj]

Is there anyway to put a shift lever in to shift the tcase when you want to?

 

[topo]

I don't know. at one time I think Boyce Equipment could make this transfer case a two speed .

 

[Travis89xj]

Im going to have to research this a little I like fabricating, maybe I can come up with something. I would like to keep my truck mostly original, but I would like my front axle to work when I say so