Tranny fluid mystery????

[XM 2742]

I have read that automatic transmission fluid could be substituted for the 30 wt in the M211-135 tranny but do a few mods need o be made to the tranny?

My deuce went from the military to the forrest service to a fire dept to a scrap dealer before I got it and upon inspection I discovered that it has auto trans fluid.

Did the military recommend or test the auto tranny fluid idea and if so when? Did the military do the mods to the tranny and if so what mods? Is there a data plate that should document a fluid mod and if so where is it?

I intend to open and inspect the tranny but what mods should I look for?

I am just hopeing that the someone didn't just pour in some auto tranny fluid and hope for the best...........a blown tranny may be why the fire dept got rid of the deuce.

Any input on this problem would be appreciated.

 

[M543A2]

I used an M-135 for over 20 years for hauling grain, stone, pulling an implement trailer, and with a 11' snow plow in the winter. When I bought it, I saw it had engine oil in the transmission, so I went to the local transmission shop to talk with the owner, who had worked on these transmissions in the military and also built the civilian version for racing. He said to definitely get the engine oil out of the transmission and put Dexron in it if I wanted it to live. He said the shear and detergent qualities of the engine oil were all wrong for an automatic. The military did it, in his opinion, to keep from complicating the supply lines. I drained the transmission and converter, put Dexron in it and ran it for 500 miles. I then drained it again and put in fresh oil to make sure it was cleaned out by the Dexron. I ran the truck under demanding conditions for the whole time I owned it with no transmission problems. No modifications to the transmission were made. I did make sure the oil cooler at the front bottom of the trans oil pan was clean. Remove the front cover after draining coolant and wash it out with a hose. I also paid attention to the exterior band adjustment at the top of the valve body casting.
I would keep the Dexron no matter what the military recommended. I feel my experience bears out the wisdom of that decision. I hear so much about how weak these transmissions are, and I think the engine oil is the biggest cause. I worked my truck hard, but did not abuse it. I also learned how to shift the transmission to get the RPM to go higher for better power between gears. I would pull the stick into "hilly" after each shift until the RPM reached the desired level, then move the stick to "level" for the next shift, and so on.
Regards Marti