Re: [MV] M-54 transfer case ?

From: David Cole (DavidCole@tk7.net)
Date: Mon Apr 14 2003 - 08:18:58 PDT


If you have a sprag based transfer case, the front axle engages when the
rear wheels slip by certain percentage. (I don't recall the specs) A
sprag is a device that looks a lot like a roller bearing, but instead of
having round roller, the peices between the inner and outer race are sort
of oblong and designed to jam when the inner and outer race move in one
direction. (If you saw one, you would instantly understand how it does
this.) I believe the M54 transfer case has two sprags, one for forward
motion, and one for backwards motion. There is a shifter that is air
powered via a cylinder built into the transfer case that engages either the
forward sprag or the reverse sprag. The transfer case is really just a big
two speed transmisson with a front drive shaft driven via the sprag
mechanism. The case on my M51 is very large, but that makes sense since
the gears themselves must be large to handle the full 1st gear torqe coming
from the transmission. I've found my M51 to be pretty simple once you
figure it out. Everything is just simply massive. When people ask me
what the 602 cu inch gas engine looks like, I just tell them to picture a
chevy 250 six cylinder on steroids. I've used my "civilian" el-cheapo
engine lift to pull the brake drums and avoid a hernia. I always wondered
why Napa sells brake drum carts for Semi's, now I know why. Installing and
removing tires takes some getting use to also. But I've found that a
square nose shovel is invaluable in shuffling the tire and wheel into
position. No dead lifting here. My slight 250 lb frame can't take stress!

Dave

>>>>>>>>>>>>>>>>>>>>>>>

On Sun, 13 Apr 2003 22:32:08 -0500, Adam Suess <ajsuess@hotmail.com> wrote:

> Is there a way to disengage the front axle on a M 54 with out removing
> the drive shaft? A sprag is a over running clutch right? So the front
> axle could free wheel around corners? I'm clueless as to what’s inside
> the transfer case and how it's suppose to operate. Thanks, Adam Suess
>
>
>
>
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-- 
Dave


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