The truck had been running with delo 15-40 motor oil in the transmission when I bought it. They installed a trans cooler as well. The problem is it is running at a temp of 300 +. I’ve recently flush the system and put ATF in the system and it is still running extremely hot. Does anybody have any information on running motor oil in this transmission? Any tips to possibly lower the temperature of the transmission?
-
Steel Soldiers now has a few new forums, read more about it at: New Munitions Forums!
1984 AM general M923 wo/w transmission over heating
- Thread starter noslo
- Start date
Did you verify the actual temp with an infared gun? Never trust the dash gauge. If it is hot off an IR gun then heat exchanger is probably clogged up full of crap and not allowing proper circulation no matter how many coolers you add. Check the flow rate and report back. Or you may have a collapsed line causing restriction.
If it has motor oil in it, then leave it in there. Switch the DEX III if you want to but you will have to cool the transmission down. As DEX III has unlimited life span at 160 degrees.
I will add that it running at 300 degrees it will only last a few miles at that temp since the oil is breaking down at that point.
Sent from my SM-G965U using Tapatalk
If it has motor oil in it, then leave it in there. Switch the DEX III if you want to but you will have to cool the transmission down. As DEX III has unlimited life span at 160 degrees.
I will add that it running at 300 degrees it will only last a few miles at that temp since the oil is breaking down at that point.
Sent from my SM-G965U using Tapatalk
Last edited:
I did when I had the Allison in my truck. I also ran an extremely large cooler that my temps never got above 160 degrees. It takes alot to get all the fluid out. A simple flush will not get it all on the first try. Regular 10w or 15-40 is just as good as Dextron III just some folks live by it. I would leave it alone if it isn't having problems
You can also get a test kit from Blackstone labs and send a fluid sample in. It will give you a breakdown of any internal problems your transmission is having.
You would need to check your flow rate at 2 places to ensure the problem Before and after the exchanger. Simple flow rate test would be, Place the Transfer case in Neutral. Parking brake on. Take the line off the exchanger. Place in a clear container. Start the truck. Transmission in 1-3. let run till the 1 gallon container is full. Do a time lapse. Put the fluid back into the transmission. Then do the same flow rate test after the exchanger.
If there is no difference then you may have a front pump going out. It should fill that 1 gallon container within 15 seconds on both lines.
Last edited:
snowtrac nome
Well-known member
- 1,674
- 138
- 63
- Location
- western alaska
If the torque converter isn't locking up you are going to make a lot of heat too. the other thing that will fry the oil in those transmissions would be a lot of staying stopped in gear, I remember several times in korea where I was in grid lock and had to put the trans into natural to cool it down.
MAdams
Active member
- 380
- 127
- 43
- Location
- San Dimas, CA
Take Simp's advice, if you switch to DEXiii make sure to add an additional cooler. ATF doesn't handle high heat as well as 15-40 will. The radiator cooling fan doesn't come on until 190 degrees which means the trans heat exchanger will only cool to about 190
74M35A2
Well-known member
- 4,145
- 328
- 83
- Location
- Livonia, MI
The trans cooler is huge on these trucks. My trans runs cold until the trans cooler actually heats it up, then never exceeds engine coolant temp. If you are driving around empty, I doubt it is reaching 300F. Likely just sender, gauge, or wiring/ground fault.
A2 trucks have a heat exchanger and an air/air cooler. A1 trucks only have the exchanger. All that crap that builds up in the radiator you see from the coolant sitting for so long can actually build up across all the little holes in the heat exchanger and block half of it. The engine cool and run fine on a partially blocked exchanger if the truck isn't being worked.
Sent from my SM-G965U using Tapatalk