Transmission cooler for M939 series trucks, anyone done this ?

[rrrr]

At a recent mudfest my M932a1 tructor tranny got warm 275 degrees (I had dex 3 in the tranny). I was doing some heavy pulling. The engine temp stayed cool and since my pulling speeds were so low the tranny never got good cooling. I did change the fluid and drop the pan and change the filter after the event since my truck started shifting down hard. The new fluid and filters fixed this.

I've been thinking about adding a tranny cooler to the front of the radiator. Has anyone done this ?

Hayden makes a heavy unit that lists the MT654 on it on an online site.

The unit is a Hayden oc-1292.

 

[jedawson1]

?

 

[Cannoncocker]

Trans cooler for M923a2

Great idea. Here in the desert where temps can exceed 120 degrees keeping any automatic transmission cool is problem. Even before I bought my M923a2 I was kicking the idea around as to an extra trans cooler and how to best go about it. HD would be an understatement for off road conditions. Keep us up to speed on what you come up with. Thank, John

 

[trooper632]

I believe the a2 trucks already have them installed

 

[Derrickl112]

I believe the a2 trucks already have them installed

Both of my m939a2's have one.


The FMTV's have a large cooler with two electric fans.

 

[quickfarms]

Interesting idea. Does the truck have a cooler from the factory?

 

[rrrr]

Yes the trucks have a cooler but I found under heavy load pulling my transmission heated up. Yes my transmission and cooler are fine. This was pulling trucks out of the mud all day. Frequently trucks their trailer and mud trucks on the trailer all at once. They added better coolers to the A2 trucks for this reason.

The cooler uses engine coolant to keep it at a constant temp. During heavy long pulls the transmission will heat up beyond the capability of the cooler to cool.

 

[Castle Bravo]

All M939/A1/A2 trucks have a transmission oil cooler, which is located above the passenger side frame rail next to the engine. M939A2s have a power steering cooler in front of the radiator.

 

[Suprman]

Do all the trucks have the same power steering pump I thought they all had the same coolers. I just figured the trans cooler was built into the radiator.

 

[Cannoncocker]

I have yet to find the trans cooler on my M923a2? Will keep looking! Next move would be an after market HD unit to upgrade from stock. The bigger the better!

 

[jw4x4]

If the engine stayed cool, the fan actuator was likely not engaged due to the temp not being high enough. If this is the case, a remedy would be to install the 2 bolts which lock the fan to the pulley, bypassing the air clutch. The fan runs all the time. Just remove and stow the bolts at the conclusion of the event.

 

[rrrr]

If the engine stayed cool, the fan actuator was likely not engaged due to the temp not being high enough. If this is the case, a remedy would be to install the 2 bolts which lock the fan to the pulley, bypassing the air clutch. The fan runs all the time. Just remove and stow the bolts at the conclusion of the event.

As I mentioned earlier the engine temp was fine and the fan actuator worked as well. The tranny cooler on these trucks just couldn't keep up with the heavy use. My engine temp stayed cool.

When I get a chance, I'm going to look at the system and see how easy it would be to add it in. I was hoping that someone else already had done something like this.

 

[rrrr]

Watch the video at 15 seconds in. I was doing this for over 5 hours straight. The mud was deep and like glue.


https://www.youtube.com/watch?v=uii3H7FyIZE&feature=youtube_gdata_player

 

[wheelspinner]

What about stacking two standard units in series?

 

[rrrr]

The units use engine oil to heat/cool tranny fluid. Way too many connections and I can only imagine a stock cooler costing a lot more and not working as well.