Converting M923 over to Transmission Fluid

[CES 3245th]

Converting M923 over to Transmission Fluid???? I saw where they used NAPA heavy-duty tractor hydraulic and transmission fluid. Pros and Cons anybody?? Easy now, it’s just a question!!

 

[simp5782]

Converting M923 over to Transmission Fluid???? I saw where they used NAPA heavy-duty tractor hydraulic and transmission fluid. Pros and Cons anybody?? Easy now, it’s just a question!!

There are alot of threads on this but its mostly personal preference.
If its not broke, leave it alone.


You can run dextron. The con is that you have to get a bigger cooler to keep the temp down. The heat exchanger especially in the summer is not good for the transmission. Since your engine is using coolant to cool the transmission. The heat cant get gone fast enough. Especially ATF is happy under 180 and has unlimited life expectancy under 170. I went to a large air to air cooler bypassing the heat exchanger and my trans temp in july went from 225 towing to 160 and never moving above it even on mountains. The engine coolant has alot to do to cool itself, the engine oil, and transmission.

Ill add that i killed 2 MT654s and i know one was from heat.

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[Swamp Donkey]

Yay! Another oil debate...

15W40...just because.

 

[Lukes_deuce]

Simp,

To clarify, did you still use engine oil after you went to an external cooler? Did you change plumb the trans into a normal transmission cooler and put it in front of the radiator? My temps were fine lately, around 200-225 but its not even hot out and I wasnt loaded down. I personally dont think the the coolant heat exchanger is a good idea and would eventually by pass it for the trans.

If staying with 15-40, do you need to change anything on the truck?

 

[simp5782]

Simp,

To clarify, did you still use engine oil after you went to an external cooler? Did you change plumb the trans into a normal transmission cooler and put it in front of the radiator? My temps were fine lately, around 200-225 but its not even hot out and I wasnt loaded down. I personally dont think the the coolant heat exchanger is a good idea and would eventually by pass it for the trans.

If staying with 15-40, do you need to change anything on the truck?

I had dextron. Only because i had taken the trans apart before i installed it. I had a large cooler made to my radiator in a swap i did. I dont have a Allison anymore. But i noticed that temp drop on that. A2 trucks have an air to air cooler and heat exchanger if that tells you anything.

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[TheBigOldSarge]

just going to put my 2 cents in: I was going to use this, cause I got it at the GA. Rally! But once you change over can you go back??? t

a U-Tube

 

[TheBigOldSarge]

Check out U-tube there is lots of Video about Pro's & Con's.

 

[simp5782]

Like i said. Its personal preference. I ran dextron and i had ok luck. I do work a 5 ton harder and put more miles than everyone on here. That led to my allisons going out more than anything.

Csmdavis will tell you KISS. Keep it simple stupid. If its operating fine leave it alone.

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[TheBigOldSarge]

Roger / I agree with that. it is easier. any one need some

 

[Csm Davis]

Thanks Simp and it is not 15w40 that was used in 99% of these trucks it is 10wt engine oil that they were all built with. The 15w40 was a change in the manual and didn't get done to most of these trucks. RSMS even used 10wt whe they were doing complete rebuids up through 2013.

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[CES 3245th]

How about this one....Has anybody used Allison Approved TES 295® automatic transmission fluid in their 5 ton?? Any thoughts or opinions??

 

[simp5782]

It is just a fancy name for Dextron and Allison now swears by it to "handle their warranty" yet years ago they swore by Dextron. It isn't worth the money honestly. It will run on any fluid.

The military uses 10w and 1540 for logistical purposes. The military even says you can put water in it in an emergency and it will operate. You can put whatever you want in it, your pocketbook.

 

[juanprado]

The decision was made for me as it was already dexron for my M923 from Ft. Polk. I have changed the pan filter once and the spins on yearly and had no issues. It also "feels" like it shifts better than other trucks I have been allowed to drive but that has many variables....

but I also rarely tow more than some limited stuff or carry heavy weight in the bed and Do not circle the globe repeatedly like Simp

 

[Csm Davis]

How about this one....Has anybody used Allison Approved TES 295 automatic transmission fluid in their 5 ton?? Any thoughts or opinions??

Here's the biggest reason to stick with what you have, half of the people I have talked to about changing thier 5 ton out to the tes 295 have had the transmission fail after changing. They have enough money that they said they were going to do it anyway and they had to replace the transmission.

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[check58]

Our Allison guy doesn't use TES on our older trucks, when I asked, he says "I'm not sold on that stuff". He's pretty good at what he does, I can't think of a time we've had to take something back to him; considering it's a 30 mile drive, I'm happy to have his expertise. Being that these are basically stock Allison transmissions, I'm curious what causes these transmissions to fail after a fluid change. I wonder if the new stuff dislodges some large pieces of sludge or something... It would be great to have an oil analysis on a failed transmission.

 

[Csm Davis]

Our Allison guy doesn't use TES on our older trucks, when I asked, he says "I'm not sold on that stuff". He's pretty good at what he does, I can't think of a time we've had to take something back to him; considering it's a 30 mile drive, I'm happy to have his expertise. Being that these are basically stock Allison transmissions, I'm curious what causes these transmissions to fail after a fluid change. I wonder if the new stuff dislodges some large pieces of sludge or something... It would be great to have an oil analysis on a failed transmission.

Pretty sure it is the heat, like Simp said the dex type fluids don't like temps over 180 and these trucks were designed to use the 10wt and normal temperature of 210 or more which is fine on 10wt or most hydraulic/ transmission oil. What everyone needs to remember that these trucks were designed by engineers not just slapped together by a couple guys in their garage. So yeah 15w40 is for Logistics but 10wt wasn't, in 83-4 it was considered a heavy duty oil by Allison and would allow the transmission to be run hotter, so less cooling system requirements.

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[CES 3245th]

Thanks Jeff for that info! Do you have any recommendations for a particular 15w40 brand??? Also in these types of vehicles & transmissionswould be advised to stay away from the synthetic oil?

 

[vvwilkins]

Regarding Using TES-295 (aka TranSynd)

Yes. I run this in my 1ton Duramax dually and just converted my M923A2. Works great and specifically designed for Allison heavy duty transmissions. My truck had 10w oil when I bought it. Shift quality improved considerably after the conversion. Others have different experiences.
-V

 

[simp5782]

Regarding Using TES-295 (aka TranSynd)

Yes. I run this in my 1ton Duramax dually and just converted my M923A2. Works great and specifically designed for Allison heavy duty transmissions. My truck had 10w oil when I bought it. Shift quality improved considerably after the conversion. Others have different experiences.
-V

A2 transmissions have both a heat exchanger and an air to air cooler. It would be any anyone who is towing with an A2s best interest to get the heat away from the exchanger and engine in the summer months and run the strict air to air or even a bigger air to air. Heat is the killer. It may run fine on trans syn for awhile and never have a problem. People who work the trucks it may not last as long.

With the engine getting hot and it trying to cool the oil plus the transmission and torque converter head thru the back of the engine the cooling system on the truck can only do so much so temps do climb. Then factor in your EGTs it gets to be constant issue. Especially towing.

Added a chart of the temps for ATF.

 

[vvwilkins]

A2 transmissions have both a heat exchanger and an air to air cooler. It would be any anyone who is towing with an A2s best interest to get the heat away from the exchanger and engine in the summer months and run the strict air to air or even a bigger air to air. Heat is the killer. It may run fine on trans syn for awhile and never have a problem. People who work the trucks it may not last as long.

With the engine getting hot and it trying to cool the oil plus the transmission and torque converter head thru the back of the engine the cooling system on the truck can only do so much so temps do climb. Then factor in your EGTs it gets to be constant issue. Especially towing.

Added a chart of the temps for ATF.

Definitely like your suggestion of larger Air-2-Air exchanger. Putting that on my list. Thanks!
-v