M939a1/M939A2 transfer case model?

[SLOrazorsedge]

I'm looking at buying a back up transfer case for my M939A1/A2 trucks. I'm looking at a Rockwell Mod#1130 but have been told the Mod #1138 is the right one. The Mod #1130 looks correct. Anyone confirm which is correct? Thanks guys.

 

[tobyS]

Here is a good place to start. Not exactly your questions answer but some finer points discussed.

http://www.steelsoldiers.com/showthread.php?59654-M818-Transfer-Case-Upgrade-T-138-to-T-1138

 

[SLOrazorsedge]

Thanks TobyS, I found that before I posted, just added to my uncertainty on 1138 Vs 1130 transfer case for the M939's...

 

[tobyS]

I don't get hits for the T1130 that are readily identifiable. One says this (not a 939 thread);

Transmission: Twin disc Model 1130 Automatic,
(4 forward, 4 reverse with integral transfer case )

Google does not do much better.

 

[jcappeljr]

I have a good take out transfer case from a M929a1.$700

 

[tobyS]

How do you know that what you say you're "looking at" is in fact an 1130 and not an 1138? By google images, the 1130 and 1138 look alike. Hope someone knows the difference. I can't find much on an 1130 to compare or what they came in. What else have you come up with? Maybe it has something to do with ratios. I vaguely remember one to one and overdrive discussion.

edit; Looked back and found the T-138 is a 1/1 ratio (engine to rear axle) and the T1138 is .73/1. (both axles) thus ENTIRELY different.

When in the middle of a rebuild of what was a new old stock T-138 in my 817 that was set up wrong in the bearings, I tried to find good info about the TC and became very frustrated. At least you have time, not in a hurry.

I'm still trying to understand the differences.