MT654 Allison Transmission

[CaptainBillUSMC]

Hello!

I've read the TMs for my M925A2 truck, include the Lube Order as well as the -10. I also read the manual from Allison that I found on here. The TMs talk about using motor oil, depending on ambient temps. I live in East Tennessee. Rarely get to neg temps. Been here 5 years and I think it's gotten below 0 (2) times. So, according to the TM, I would be fine to use 15W40. My choice would be Shell Rotella. Allison says you can also use Dexron III.

When I pulled the dipstick, I noticed it isn't 15W40 in there. It's amber/honey color, doesn't smell like motor oil, and is thin. Drips right off the dipstick, hot or cold. When I pull the crankcase dipstick, the oil stays in place. That tells me that it's either HDO10 or its hydraulic oil (which is scary).

I was hoping you all could share your experiences with me:
-For those that run with 15W40, have you experiences any long term issues?
-Any truth to the notion that running 15W40 causes higher trans. temps and increases wear?

-For those who converted to Dexron III, what has been your experience? Better, worse?

-Has anyone ever used Lucas Oil Stabilizer in the transmission as an additive? I am not a fan of snake oil, but i am a fan of that particular product as an additive.

I know some of you probably would like to know if I am experiencing any issues. Just the typical hard down shift from 2d to 1. So why mess with it? Well, my thinking is I don't know what was used in there before. And the filter is a Fram and I don't like Fram. The oil looks good, I just don't like not knowing what is in there.

Thank you for your time.

-Capt Bill

 

[juanprado]

Sir, you are correct Fram is poo

I would recommend you change the internal pan filter also.

Mine came with dexron already changed when I picked it up directly from Ft. Polk. Mine shifts great and no issue. I do not carry weight and tow small trailers occasionally.
Btw, O'reillys still sells old school dexron in gallons. I sold auto parts in another life and prefer atf as it has specific additives for transmission not found in plain old motor oil. Ymmv

If you convert flush and try to get as much out as you can.

Lots and lots of threads on here on what fluid to use.

Many who carry lots of weight use with heavy trailers prefer 15w40.

Some have changed to the newer approved allison fluids that are more expensive.

 

[CaptainBillUSMC]

Sir, you are correct Fram is poo

I would recommend you change the internal pan filter also.

Mine came with dexron already changed when I picked it up directly from Ft. Polk. Mine shifts great and no issue. I do not carry weight and tow small trailers occasionally.
Btw, O'reillys still sells old school dexron in gallons. I sold auto parts in another life and prefer atf as it has specific additives for transmission not found in plain old motor oil. Ymmv

If you convert flush and try to get as much out as you can.

Lots and lots of threads on here on what fluid to use.

Many who carry lots of weight use with heavy trailers prefer 15w40.

Some have changed to the newer approved allison fluids that are more expensive.

Thank you! I saw the threads for the fluids. I just wanted to get an idea for how everyone's transmissions are holding after using 15W40 vs Dexron III. That's good advice on changing the internal filter. I am going to check out O'reillys. Thanks again!

 

[muthkw25]

I run amsoil in my transmission and its fantastic. I swapped fluid and swapped spin on filter and ran it 500 miles and then did a drain and swap changing both filters again to convert it all over. Highly recommended.

 

[ericp351]

I doubt the 15w 40 will make trans run hot. Mine don,t, probably colder, loaded, as said above. Option 3, or 4, may be universal tractor fluid. More or less 20 wt. Has some EP additives. Less solvent and slightly thicker than AtF. Probably like obsolete trans oil type A. Affordable, and may provide smoth shifts lightly loaded, as ATF. Good luck.

 

[juanprado]

Check the allison website for approved fluids.
Not sure universal tractor fluid is one

 

[ericp351]

I highly doubt that it would be listed. To be clear, I tried to list it as an alternative. Way better than hyd oil listed in the original post. Slots in between crude, but very effective motor oil and transmition oil . It works in simple transmittions, rear axles, and hydraulics. I think something to consider if on a budgit, want smooth shifts, but a bit more "beef" than the lattest trans oil. That's it.

 

[CaptainBillUSMC]

Thanks to everyone who took the time to respond. After some thought, I am going to change the fluid and both filters and fill with 15W40. I hate to do it because the trans fluid is so clean, but it's thin and I have no idea what fluid it is.

 

[Mullaney]

Thanks to everyone who took the time to respond. After some thought, I am going to change the fluid and both filters and fill with 15W40. I hate to do it because the trans fluid is so clean, but it's thin and I have no idea what fluid it is.

.
Well... You could order a sample kit from Blackstone or somebody like that.
You could sample the oil and have them test it and tell you what it is...