This is weird, elevated transmission oil temp from truck sitting idle?!

[PapaPumpSD]

I started up my M925A2 after it sat in a snowstorm for over 4 hours. It was freezing out so I let it idle for around 15min. at ~700 rpm. When I get into the truck I noticed my trans oil temp was over 160 degree F and my engine temp was not even 120 F yet. Why would my trans oil temp be elevated from just sitting idle????

Note: Recently the truck's transmission oil temp has been hitting nearly 275 F while driving it just 6 or so miles (unloaded). Something isn't right and some of your guys mentioned a few things that could be the cuprit. But this elevated trans oil temp from sitting idle is strange.

Thanks all,

Brent

 

[Artisan]

Is the winch PTO engaged?

 

[Swamp Donkey]

Check the temp of the transmission with an IR temp gun. Don't trust the gauge.

 

[BenRoberts]

I had a gauge go wacky on me, I would tap it and it would shoot way up and tap it again it would go back down

 

[Jason O]

You may have the wrong temp sender installed in the transmission. One of my trucks did the same thing. Gage hit 275, and I freaked out, pulled over, tested with an IR and it was less than 160.

If you don't have a way to test temperature, but you can safely touch the transmission sump for a few seconds with your hand, it's not 275 deg.

 

[PapaPumpSD]

Thanks for the responses everyone! The winch PTO is not engaged. The tans temp gauge is loose (it wobbles in the gauge mount) and it does jump around a bit when bumped. I'm going buy a new trans temp sending unit and gauge but I cannot for the life of me find the NSN for the trans temp sending unit. Can someone please let me know the NSN for this part?

The only info I could find in the TM that might relate to the trans temp unit is NSN 6685008145271, P/N MS24537. See TM 9-2320-272-24P-1, Figure 146 & page 146-1 which calls out the items for "LOW AIR WARNING SWITCH,MECHANICAL TACHOMETER,TRANSMISSIONTEMPERATURE TRANSMITTER, COOLANT TEMPERATURE SENDING UNIT, OIL PRESSURE TRANSMITTER, AND STOPLIGHT SWITCH"'

Thanks again gentlemen. I really appreciate your help!

Brent

 

[Swamp Donkey]

The gauge grounds through the mounting bracket. Pull the panel, tighten the bracket and see if that helps. You'll have to do this anyway if you replace the gauge so you may as well see if the original is working with a good ground.

Gauge and sending unit links below. You can buy from him or find all the information your looking for in the descriptions.

Gauge
http://www.eriksmilitarysurplus.com/tega10f11.html

Sending Unit
http://www.eriksmilitarysurplus.com/teseunwirush.html

 

[PapaPumpSD]

Is the winch PTO engaged?

Great thought. I checked it and it wasn't engaged. At this point I'm pretty sure it's a faulty gauge as I can put my hand on the trans oil pan and it only feels warm when the gauge is reading >175F. I bought a new gauge and I'll try to get it installed by this weekend.

Brent

 

[PapaPumpSD]

The gauge grounds through the mounting bracket. Pull the panel, tighten the bracket and see if that helps. You'll have to do this anyway if you replace the gauge so you may as well see if the original is working with a good ground.

Gauge and sending unit links below. You can buy from him or find all the information your looking for in the descriptions.

Gauge
http://www.eriksmilitarysurplus.com/tega10f11.html

Sending Unit
http://www.eriksmilitarysurplus.com/teseunwirush.html

Thank you Swamp! We'll tinker with the ground this week. I bought a new gauge so I'll see if we can get this squared away. I do believe it's a faulty gauge at this point but it's only an assumption so I won't drive the truck until I get this remedied. Bummer!

Brent

 

[74M35A2]

To make it even easier, shoot the IR gun at the spin on trans filter.

 

[Swamp Donkey]

The temperature sending unit is accessed through the door in the floor on the A0/A1 models. Most likely the same for the A2 but I'm not sure. I'd shoot the temp where the sender is installed for comparison with the gauge. You can do this without getting out of the truck if it can be done through the door.

 

[PapaPumpSD]

Well, I replaced the trans oil temp gauge and all seems to be okay. As an insurance policy, I purchased an IR gun to verify the gauge is working properly.