transmission oil change for HEMTT

[2deuce]

I've got an unknown oil in the transmission. It looks like motor oil, if I was to guess. It's a very dark amber color. I've read that Allison recommends to drain the transmission, and put on a new filter, then fill with TES295. Then run for 30 minutes, then repeat, which then should give about 80-90% TES295 in the transmission. Have any of you done this? and if so how much does drain out? Thanks

 

[simp5782]

It is 15w40 weight oil. Military standard for that truck. 31qts for mechanical transmission. 36 w/out filter and 37qts with filter for the electronic.


Consult LO 9-2320-279-12
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[2deuce]

Those numbers of quarts would be for a new transmission or a rebuilt one that is dry. A used transmission will not fully drain. I'm wondering how much will drain and what will that 15w40/TES295 mix be like. Allison says only to drain and refill again after running 30 minutes with the end result having TES295 being the predominate oil and not requiring another change for 100k. I'm guessing about half or a small amount more of the total volume can be drained from the pan. After 1 drain and refill 50/50 ratio, and after the 2nd 75/25 (if my guess is close). Being the recommendation is drain after 30 minutes tells me a 50/50 mix is not good and the 30 min. is given to get the 2 oils well mixed before draining again.

This will cost close to $400 to reach this point. Napa has TES295 on sale this month.

 

[simp5782]

Those numbers of quarts would be for a new transmission or a rebuilt one that is dry. A used transmission will not fully drain. I'm wondering how much will drain and what will that 15w40/TES295 mix be like. Allison says only to drain and refill again after running 30 minutes with the end result having TES295 being the predominate oil and not requiring another change for 100k. I'm guessing about half or a small amount more of the total volume can be drained from the pan. After 1 drain and refill 50/50 ratio, and after the 2nd 75/25 (if my guess is close). Being the recommendation is drain after 30 minutes tells me a 50/50 mix is not good and the 30 min. is given to get the 2 oils well mixed before draining again.

This will cost close to $400 to reach this point. Napa has TES295 on sale this month.

If you are switching to dextron then go get an electric diesel transfer pump from harbor freight. Hook it to your trans cooler line, put your other line in an empty bucket. Go ahead and get 10 to 15gal of dex in buckets. Run the truck with that pump pushing new fluid in like a transmission flush machine. I do it on the 600 series allisons. You also have to keep the transmission temp with dextron under 220. The cooler the better. Under 180 degrees it has a 100k mileage rating.

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[Csm Davis]

I've got an unknown oil in the transmission. It looks like motor oil, if I was to guess. It's a very dark amber color. I've read that Allison recommends to drain the transmission, and put on a new filter, then fill with TES295. Then run for 30 minutes, then repeat, which then should give about 80-90% TES295 in the transmission. Have any of you done this? and if so how much does drain out? Thanks

Have you heard about anyone having transmission trouble with the engine oil being used? I personally wouldn't change it to anything but what the military used unless you are installing a new completely rebuilt transmission. I have heard to many guys that swapped to dexitron in their 939 trucks and lost the transmission. Your truck but unless you are getting a guarantee or warranty from someone that it won't mess up a transmission to swap I wouldn't do it.

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[2deuce]

I'm not switching to Dextron. I'm switching to the Allison recommended oil TES295. Like I said in my 1st post... I'm not sure what oil is in there. It only looks like motor oil to me. My oil level is just at the bottom of the stick when running cold and only a little higher when hot running. I don't know(have no experience adding oil to this truck) how much it will take to be in the safe zone on the stick, but at $38 a gallon and the fact the oil looks like it needs a change, being the color I described in my 1st post, and since I need to add oil and I don't know what is in there, I figured the safest oil to replace would be the allison recommended TES295.

Now I see where people have stated that the military used motor oil over the correct oil only because they didn't want to stock specific oils and have one oil common in all vehicles for ease of logistics. My truck also came with what looked like a high sulphur 15-40wt in the engine and not a recommended oil by Detroit. It is plain to see longevity of the engine was not high on their list of importance, which suggests the same thoughts on the transmission.

Now I know you guys are trying to help, and I appreciate that, but the thread is going in the wrong direction for me, because assumptions were made about dextron. I don't know how I can be more clear on my intentions.

Thanks

 

[2deuce]

I will also add in response to Csm Davis, I have no maintenance records on the truck. So I don't know what oil is in there. I have seen it stated that all transmissions came with allison approved oil when new, not the military approved oil. There was a hint of pink on the dip stick when I wiped it the 1st time and the Austran TES295 I bought is pink. I don't know the color of all the Allison approved oils that are TES295. I'm guessing they would be the same color, but I don't know.

Being I shouldn't drive the truck low on oil and I thought I shouldn't add an oil not approved by Allison. I can't say with any certainty what is in there now....brand, type or weight. Plus the fact that the military had reasons other than longevity in their oil choice. My bottom line is I want this transmission to last as long as I own the truck and the cost of oil is not a factor.

Thanks

 

[simp5782]

Follow the LO the military put out. Its also cheaper. Plus saves headaches. Put 15-40 in it. Unless you want to try to swap it all out. And it will take 3 drain and refills to get it all by draining the pan. I bet your HT740D does not even come back in the Allison system since there is a thread by Suprman in which allison says they dont even make it.

https://www.steelsoldiers.com/showthread.php?t=122393

If you are unsure of the oil send it out for an oil analysis. It will tell you the weight as well as its life left and any contaminants in the fluid.

Transmission life is beyond any relm of your control. Sorry. There is no quality assurance in the military production of parts. A new rebuilt transmission out of the can may not move an inch. Your transmission may last 200 hours or 20,000. You dont know. The allisons in the 600 series go out on just a wim. Like the guy who used his crane now it wont come out of reverse.



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[simp5782]

Also up until 2010 Allison authorized the use of Dextron in its transmissions. Your transmission would fall under the pre 2010 I believe in which they authorized dextron and not transyn to be in it. So you can run either per the bulletin. Your 700 series transmission is listed below. It also says that SAE 30 and 15w40 are approved fluids.

http://www.lubegard.com/pdfs/allison_techbulletin.pdf

Also in the words of Swampdonkey on Allison. If your truck tire rolls onto grass then Allison considers that Severe Duty.

 

[2deuce]

Thanks simp5782 for your thoughts and the links. I just talked to a couple of guys in my club that have this transmission in their trucks(not HEMTTs) and they run 5-30wt. They said that is what the military runs. Nothing is very clear to me on this. They also said that 3 drain and fills would be required for a drain plug change. I guess what I need to figure out is whether or not there is a benefit in changing to TES295/transyd. It seems that what I have is 5-30wt motor oil in there now. My club members thought to top up with more 5-30wt and run it.
With what the military used for oil in my 8v92 detroit diesel, I just don't trust their decision on transmission oil.
I want to go with the best chance for a long lived transmission, what do any of you guys with this transmission run in it and why???

Thanks

 

[simp5782]

Well. Like the guy who keeps dropping liners in his NHC250 cause he is using the coolant "cummins" recommends. Yet he is having issues cause it is the latest and greatest stuff. Well the military wanted it simple. CSMdavis says it alot. KISS keep it simple stupid. Most of the military oil is straight 10w in the other allisons. They seem to work alright. I am sure transyn is like dextron. It has to stay cool to work right. The m939 trucks run a heat exchanger and i saw temps of 240 on the transmission. Then it makes the engine work harder. So not sure what the optimum trans temp is for transyn. Or synthetic dextron but i would check that vs what your trans gauge reads. I would run an oil analysis on it and see what it says.

I have killed 2 mt654s in a 9months. I am sure it is due to heat from towing. Each lasted a lil over 30k miles.

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[Floridianson]

My club members thought to top up with more 5-30wt and run it.
That heavy of a machine and what you might be doing with it I would stay with 15/40. Also I have 3 military trucks the run 15/40 in there transmission and I am not going to switch till they need a rebuild if ever.

Transyn is a good product for machines that put on lots of miles and have the fluid change. You save money with Transyn because the cost of fluid changes as you get more miles with it. My guess we do not put that kind of miles on our machines.

 

[JDToumanian]

I switched to Transynd in my HEMTT, but I don't remember exactly how much came out when I drained it... I want to say just under 10 gallons. I brought 15 and had around 5 gallons left.

Personally I think switching is the right thing to do, but I acknowledge that a transmission with a lot of wear from using 15w-40 could fail afterwards. That's why I bought a new transmission in the can to have as a spare but per Murphy's Law just having the spare probably guarantees I'll never need it.

There's a lot of info out there about using motor oil... A retired Allison engineer who posts on the Bus Nuts forum I occasionally read and whose opinion I value, says that the motor oil spec was always a poor compromise for severe situations that would cause Dexron to burn, but once TES295 came about, there is NO situation in which motor oil is superior. That is why I switched. He says the motor oil spec is still there because the military refused to switch to TES295 and insisted that they continue to allow it.

Jon

 

[Swamp Donkey]

Also in the words of Swampdonkey on Allison. If your truck tire rolls onto grass then Allison considers that Severe Duty.

Whoa whoa whoa...don't put me in an oil debate. When it comes to oil, there's a fence. There's people on either side of it, and some that sit on it, but none of them will ever agree. I'll play for a second but you'll get no opinions from me here.

I'll stand beside my statement though, as will Allison. If you want the proof then Google is your friend. I read black and white print just fine but I'm terrible at making sense of opinions and assumptions. I'm from the 15w40 "mafia" but will keep my research and reasoning to myself. I don't hold grudges or start battles over what everyone decides to use. Run what makes you happy and content...

I'll offer a fact to help you in your decision though, 2deuce. Different lubricants create different wear patterns on what they lubricate. If you swap lubricants during the service life of a part, you abruptly change wear patterns. Moving parts don't like abrupt changes. It's the same reason it's ill-advised to swap from natural to synthetic fluids in differentials, T-cases and such....different wear patterns. Unless your transmission was just rebuilt I'd run what's already in there. Plenty of testing by people and companies, in many different industries, with way more money involved than me to back me up on that. New or fresh rebuild isn't much of an issue. Drastic changes in fluid type after the part has been in service is asking for trouble.

15w40 tends to be a darker amber. If it doesn't smell burnt or look milky/contaminated I'd top it off and ride off into the sunset. As far as the pink on the dipstick... dump it and refill with the same thing already in there if you like. As Simp said, you can't control when a transmission decides to fail. You can **** sure develop a migraine while worrying about it though.

Ok...one more tip. A quick, down and dirty test to see what oil it is. Take a small sample and put it on a piece of metal. Burn it with a torch and take a whiff. If it smells like motor oil then it's 15w40. If it doesn't, then it is most likely straight 10w, the other common oil the military used in transmissions. Straight 10w is more of a hydraulic fluid and doesn't smell like motor oil when burned. Since it's golden in color we can be pretty sure it's not transmission fluid, which would have its own unique smell due to the additive package in the oil.

That's it. No more from me on the subject. Swamp Donkey out...

 

[Floridianson]

Don't know if I believe everything on the Web but found these figures on regular transmission fluids versa miles and heat.
Yea I remember that same engineer Mr.Johnson aka Mr. Transynd and I had a thread from him where he stated that at the time the C4 or the motor oils were ok by him and Allison to run in the heavy use military transmissions. Straight 40 weight for hot days and nights and 15/40 to better cover the different ambient temperatures. Looks to me it's all about the heat and if we can keep it down with the fluids that might be run. Your truck your call.

 

[2deuce]

I believe in keeping it simple, but I don't like the stupid. I can see where the military wants one oil, or one fuel to fit all, but they can afford the consequences or lay a heavy hand on the manufacturer to keep their lucrative contract. The fact that they can drop in a rebuilt detroit in a HEMTT every 20K from using the wrong oil tells me something about the stupid in their mindset. Their reasons are going to be much different than mine and could be understandable from their point of view. I changed the oil in my engine to Delo 100. I'm almost certain I'm going to change to TES295 in the transmission also. I don't understand how one oil is going to benefit the transmission over another, and because of that I have to trust Allison the maker to recommend the best oil, not a user, that has different reasons or criteria or goals to meet than my own. I have thought all along that TES295 is the best. As an owner the decision to switch is weighed by cost and benefit. I'm agreeing with JDToumanian's conclusion to switch. I could do an oil analysis, but I wouldn't understand the result, for one reason I don't know how long since the last change, there are other factors too.

Jon, did you change your oil more than once? If not the percentage of old to new is still high since only about half drains each time you change it.

I'm hopeful other owners continue to share there reasons for running the oil they do, with their successes and failures, but if they do what they do because the military does it, they may want to reconsider, that being my opinion.

Whether I switch or not(I think I will) I will post here any results I find, and certainly report a failure.

Thanks to all,
Greg

 

[Csm Davis]

I'm not switching to Dextron. I'm switching to the Allison recommended oil TES295. Like I said in my 1st post... I'm not sure what oil is in there. It only looks like motor oil to me. My oil level is just at the bottom of the stick when running cold and only a little higher when hot running. I don't know(have no experience adding oil to this truck) how much it will take to be in the safe zone on the stick, but at $38 a gallon and the fact the oil looks like it needs a change, being the color I described in my 1st post, and since I need to add oil and I don't know what is in there, I figured the safest oil to replace would be the allison recommended TES295.

Now I see where people have stated that the military used motor oil over the correct oil only because they didn't want to stock specific oils and have one oil common in all vehicles for ease of logistics. My truck also came with what looked like a high sulphur 15-40wt in the engine and not a recommended oil by Detroit. It is plain to see longevity of the engine was not high on their list of importance, which suggests the same thoughts on the transmission.

Now I know you guys are trying to help, and I appreciate that, but the thread is going in the wrong direction for me, because assumptions were made about dextron. I don't know how I can be more clear on my intentions.

Thanks

I will also add in response to Csm Davis, I have no maintenance records on the truck. So I don't know what oil is in there. I have seen it stated that all transmissions came with allison approved oil when new, not the military approved oil. There was a hint of pink on the dip stick when I wiped it the 1st time and the Austran TES295 I bought is pink. I don't know the color of all the Allison approved oils that are TES295. I'm guessing they would be the same color, but I don't know.

Being I shouldn't drive the truck low on oil and I thought I shouldn't add an oil not approved by Allison. I can't say with any certainty what is in there now....brand, type or weight. Plus the fact that the military had reasons other than longevity in their oil choice. My bottom line is I want this transmission to last as long as I own the truck and the cost of oil is not a factor.

Thanks

Okay I did not say you were switching to Dextron. If you will reread what I wrote i said several 939 owners had switched to Dextron because that is what Allison recommended for their transmission. I personally think that what you are asking about is up to you as I said it's your truck I wish you all the great times in it. As I and Swamp And Simp have pointed out once a part has been used with a specific type of oil l would not change it, not sure how old you are but I can remember a time you didn't want to change brands of engine oil, they are all compatible now. I am not saying that Allison is wrong or the military is wrong, what I am saying is that Allison even says the two types are different enough that you don't want a mixture of them and I believe that is reason enough for me to never swap unless you are going with a brand-new transmission.
Now to address a mistake i have heard on here several times is that the military has removed transmission fluid from these vehicles after they got them and put motor oil in it's place. That is completely wrong, these vehicles were ordered and delivered with the oils that are listed on the data plates. I am not saying some idiot in service didn't dump Dextron in your transmission because he thought all automatic transmissions use Dextron, I have seen it done many times. Don't get me wrong I love all the service members but there are many even in the mechanics ranks I would not let work on my trucks unless I am watching everything they do. Also logistics doesn't over rule what the military uses in a vehicle if that was the case l would not have ever bought a 1200.00 dollar bucket of oil for a winch the Navy uses. If we can use one part or oil across many vehicles, we will, but not at the risk of a truck or tank failure in battle. So don't think that the military made Allison use 10wt or any other oil to save a few thousand dollars, when these trucks were originally designed the motor oil was a option for heavy duty use in these trucks and that is how they were ordered. Unless someone can find the Allison engineer that was assigned to the military projects in the early 80's and he says they were forced to agree to motor oil, I will continue to believe the Allison paperwork from that era that says these oils were approved for use not only in military but civilian heavy duty use.
We are not trying to bully you or anyone into using something to hurt a military vehicle but these trucks were and are being used with great success as ordered.

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[2deuce]

Thanks Floridianson, Cool is good, excessive heat is bad. That is all I really know about transmissions and oil. My problem is I haven't run my HEMTT in different seasons/conditions to know if I have affected a change in temperature by a change of oil. I hope others report their results.

 

[2deuce]

We can only give what we think and our opinions and I truly appreciate that from those that posted.
My truck was originally built in 1984. The properties that are built into todays oils are improving all the time whether we change to an improved version is a choice we need to make. That is why I started this thread... I'm trying to make the right choice. My truck I believe was rebuilt last in 9/2010. It has 7400 miles on it and about 600 hours on the meter. It came from the National Guard, I'm the 1st civilian owner.

 

[silverstate55]

Since you've mentioned engine oil at least twice, make sure that the multi-grade 15-40W is out of the engine; use only straight-grade SAE40 (or 30W in cold weather) LOW-ASH, DETERGENT-TYPE oil in your 2-stroke Detroit. Otherwise you'll score your liners, among other things. Shell Rotella makes a nice compatible oil that is widely available.