Use of SAE 15W40 motor oil in Allison HT746

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Use of SAE 15W40 motor oil in Allison HT746

June 13, 2011, 04:49:28 pm

I just got some quotes on 34 quarts of Dexron III ATF for a transmission fluid change. I didn't like what I heard. I looked up what Allsion specs and it appears if I read it correctly that I can use SAE 15W40 motor oil instead of ATF at 1/4 of the cost. Has anyone done this successfully? Do you have any comments?

www.allisontransmission.com/documents/product/13-TR-90,%20Rev%20E.pdf

Re: This SIL replaces 13-TR-90, Rev. D. 13-TR-90, Rev. E
Please discard your copy of 13-TR-90, Rev. D. March, 2001
This SIL includes information about Allison Product Code(s):
oil recommendations, oil specifications and Page 1 of 4
Allison/Castrol TranSynd™ 1.

The guy is coming tomorrow to do the oil change so a quick response will be greatly appreciated.

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #1 – June 13, 2011, 05:35:20 pm

Kent,

A very serious step. I have no input. Even if it is approved, I suspect its much higher viscosity will hurt performance and MPG.

But, here is a link to a retired fluids specialist with Allison. I would suggest you contact him:

RV.Net Open Roads Forum: Let Me Know if You Have Allison Transmission Fluid

Brett

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #2 – June 13, 2011, 05:38:41 pm

Quote from: wolfe10 – June 13, 2011, 05:35:20 pm

Kent,

A very serious step. I have no input. Even if it is approved, I suspect its much higher viscosity will hurt performance and MPG.

But, here is a link to a retired fluids specialist with Allison. I would suggest you contact him:

RV.Net Open Roads Forum: Let Me Know if You Have Allison Transmission Fluid

Brett

That's just what I needed Brett. The mechanic that is going to do the oil changes for me said that he had used motor oil for years in Allison transmissions, but that sure scared me. I will contact your reference and post the results.

Did you read the Allison tech bulletin that I referenced?

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #3 – June 13, 2011, 09:00:24 pm

Kent,

Below is the Private Message from the retired Allison fluids specialist:

Subject: RE: Allison fluid question
Wolfe10,

The Allison Service Information quoted in the post is obsolete. SIL 13-TR-90 is old and was replaced by Allison SIL 10-TR-99. Engine oils are no longer recommended for any on-highway Allison transmission products. They were allowed for many years but we kept having problems with them oxidizing too soon. When you miss an oil change with an engine oil, you're probably in trouble if you let it go too long.

So.......... tell this guy not to put engine oil in his Allison transmission. Either use a TES-389 or TES-295 approved product.

The latest Service Information may be found at http://www.allisontransmission.com/servlet/DownloadOnDemand?ApplicationID=155&DownloadID=5

Brett

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #4 – June 13, 2011, 09:00:24 pm

Quote from: Kent Speers – June 13, 2011, 05:38:41 pm

Quote from: wolfe10 – June 13, 2011, 05:35:20 pm
Kent,

A very serious step. I have no input. Even if it is approved, I suspect its much higher viscosity will hurt performance and MPG.

But, here is a link to a retired fluids specialist with Allison. I would suggest you contact him:

RV.Net Open Roads Forum: Let Me Know if You Have Allison Transmission Fluid

Brett

That's just what I needed Brett. The mechanic that is going to do the oil changes for me said that he had used motor oil for years in Allison transmissions, but that sure scared me. I will contact your reference and post the results.

Did you read the Allison tech bulletin that I referenced?

Kent,

Brett sent me a message and told me to answer your post. I was the former Transmission Fluids Engineer at Allison and retired in 2009. I approved all Allison fluids (on a worldwide basis) from 1990 until my retirement in 2009. I also came up with the TranSynd program and worked with BP/Castrol over a number of years to get it tested and approved. I did the same for ExxonMobil with their Mobil DELVAC Synthetic ATF.

The Allison Service Information quoted has been obsolete for a few years now. I obsoleted it. It was replaced by 10-TR-99 (now referred to as Service Tip ST1099. Engine oils are no longer recommended for any on-highway Allison transmission products. They were allowed for many years but we kept having problems with them oxidizing too soon. So, when you missed an oil change with an engine oil, you were in danger of having problems if you let it run too long.

So.......... do not put engine oil in your Allison HT Series transmission. Use either a TES-389 or TES-295 approved product. TranSynd is your best bet. ALso, DEXRON-III is now obsolete too; so, they are also not recommended. You can go to the Allison website and find a list of approved fluids.

The latest Service Information may be found at http://www.allisontransmission.com/servlet/DownloadOnDemand?ApplicationID=155&DownloadID=5

PS: I've joined this forum too and I'm here to help. Please send me a PM when you need help. Otherwise, I'll try to monitor the forum from time to time.

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #5 – June 13, 2011, 09:16:00 pm

Quote from: hzjcm8 – June 13, 2011, 09:00:24 pm

PS: I've joined this forum too and I'm here to help. Please send me a PM when you need help. Otherwise, I'll try to monitor the forum from time to time.

Thank you and Welcome to ForeForums!

Michelle

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #6 – June 13, 2011, 09:19:00 pm

Tom,
Thank you for lending your expertise to this forum. I'm sure I speak for many here that seek qualified professionals that are willing to share there knowledge.
Rick

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #7 – June 13, 2011, 09:34:23 pm

Having Tom here speaks to the quality of information and the professionalism of ForeForums. We are fortunate to have people of Tom's caliber here. He is one among many.

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #8 – June 13, 2011, 09:38:19 pm

Quote from: hzjcm8 – June 13, 2011, 09:00:24 pm

Quote from: Kent Speers – June 13, 2011, 05:38:41 pm

Kent,

Brett sent me a message and told me to answer your post. I was the former Transmission Fluids Engineer at Allison and retired in 2009. I approved all Allison fluids (on a worldwide basis) from 1990 until my retirement in 2009. I also came up with the TranSynd program and worked with BP/Castrol over a number of years to get it tested and approved. I did the same for ExxonMobil with their Mobil DELVAC Synthetic ATF.

The Allison Service Information quoted has been obsolete for a few years now. I obsoleted it. It was replaced by 10-TR-99 (now referred to as Service Tip ST1099. Engine oils are no longer recommended for any on-highway Allison transmission products. They were allowed for many years but we kept having problems with them oxidizing too soon. So, when you missed an oil change with an engine oil, you were in danger of having problems if you let it run too long.

So.......... do not put engine oil in your Allison HT Series transmission. Use either a TES-389 or TES-295 approved product. TranSynd is your best bet. ALso, DEXRON-III is now obsolete too; so, they are also not recommended. You can go to the Allison website and find a list of approved fluids.

The latest Service Information may be found at www.allisontransmission.com/servlet/DownloadOnDemand?ApplicationID=155&DownloadID=5

PS: I've joined this forum too and I'm here to help. Please send me a PM when you need help. Otherwise, I'll try to monitor the forum from time to time.

First of all Brett, thank you for saving from me some potential problems by introducing us to Tom.

Tom, we are very pleased to have access to your expertise. I have an 1993, HT746 four speed transmission. Based on Brett's concerns, I did not buy motor oil but I did buy Dexron III at $13.99 per gallon. That is a very good price and I would like to use it if possible. What would be the worst case scenario if I used the Dexron III? How long and how many miles could I safely use it?

Once again, thanks in advance for your help.

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #9 – June 13, 2011, 10:13:26 pm

Tom, I am also pleased to seeyou here, I have been following your comments on the Good Sam Forum too.
Thanks

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #10 – June 13, 2011, 10:48:27 pm

I too am getting ready to change transmission fluid. I know what a disaster having a Allison go down could be, especially if towing, lengthly overhaul time, lodging, etc. were to be considered and imagine what a retarder at the end of the transmission would add to the bill. It would be a great inconvenience to have to do a head replacement etc. on my 6V-92TA but I would cuss a thousand times a day and do it. The Allison is another matter. You almost need a clean room (perhaps you do) to overhaul an automatic and have it last the way we all would like it to. So, I guess the answer is, I can't afford to take the chance of a mechanic vs. a Allison engineer opinion. I did just a little research on pricing and have found the TES-389 to be less expensive per 5 gallon pail vs. Dextron. This fact may give some validity to the quoted forum post below. I have copy pasted the following totally without any recommendation:

Quote

BEGIN QUOTED FORUM POST

TES-389 is a spec for what used to be the DEX III stuff. When GM quit licensing DEX III in 2007, Allison had to create this new spec for people that didn't want to be forced into buying TES-295 fluids. Admittedly, TES-295's are top notch, but they are also top-shelf in price as well. Many people simply have no need for such expensive fluids.

The TES-389 fluids are verified for performance and issued licenses if they meet the criteria. It merely continues the existence of what was essentially DEX III. It also specifically address the seal compatibility issue. Any lincensed TES-389 will not cause seal issues in older Allison trannies, as I understand it. Hence, DEX VI is NOT a TES-389 licensed fluid. TES-389 is an Allison fluid license spec. DEX VI is a GM fluid license spec. They are difference products with difference construction by design.

DEX VI, OTOH, is a significant improvement over DEX III. It has 2x the oxidation and shear resistance. It is a much better fluid than DEX III, but ONLY if you can use it without fear of seal hardening in some transmissions.

GM felt that DEX VI was OK for all backwards compatibility; Allison disagrees. Hence, the serial number cutoffs for the Indy and Baltimore plants. If your truck tranny is after the cutoff, then DEX VI is a perfectly suited fluid for the tranny; not as good as TES-295, but certainly better than former DEX III products.

Allison has but two specs in regard to fluids we'd use; a premium (TES-295) and a basic (TES-389). DEX VI fluids fall in-between those two specs as far as abilities. But because DEX VI cannot pass the TES-295 standards, it gets pushed down to the same service schedule as the TES-389 fluids. But make no mistake, DEX VI can kick the butt of any TES-389 in regard to longevity. If Allison were so inclined to make a third spec, the DEX VI would likely fall in-between the others.

To put it simply, there is a "good, better, best" mentality here. Allison only has the "good" (TES-389) and the "best" (TES-295). They make no acknowledgement of "better", so anything that is "better" than "good" still gets treated (downgraded) as inferior, even though that is not the true view of things.

END OF QUOTE

There are other forums that offer other synthetic options that still meet Transyn TES-295 specs. After reading the Allison bulletin, I am concerned about changing to a synthetic and even if the torque converter were to be siphoned out, not meeting the Allison specifications until the next (expensive) change.

Let the transmission fluid wars begin!

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #11 – June 14, 2011, 07:58:10 am

Tom,

Could you comment on the time-based requirement for Transynd changes for those of us that don't accumulate a lot of miles per year? Also, what's behind the severe service designation for all Allison trannys with a retarder? Can we consider longer change intervals if we limit trans temps to some max level?

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #12 – June 14, 2011, 11:41:30 pm

Tom, sorry to bear you with another quest for your opinion, but as I use all Amsoil products ( I believe in the product) am I correct that their "Torque Drive Synthetic ATFluid" meets the specifics of Allison TES-295 and TES-389 as stated on the label?. I realise that some people are not aware of the quality of this product even though the founder was the original developer of Synthetic oils for automobile use. Synthetic oil is the only oil used in Jet aircraft I believe. I have the 4000 series trans' with retarder

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #13 – June 15, 2011, 06:52:35 am

Seems it is all perfectly clear,
Just use what ever you like and prefer price wise.
Seems common sense is out the window here.
Pay the piper when your caught.

Perfect rational thought for some
Me, I use the good stuff, do not like the price, but I love the peace of mind, as I am truely "Cheap & Tacky", but proper lubrication is cheap insurance.
I prefer to worry about other things than my transmission.

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #14 – June 15, 2011, 04:55:41 pm

Quote from: Kent Speers – June 13, 2011, 09:38:19 pm

First of all Brett, thank you for saving from me some potential problems by introducing us to Tom.

Tom, we are very pleased to have access to your expertise. I have an 1993, HT746 four speed transmission. Based on Brett's concerns, I did not buy motor oil but I did buy Dexron III at $13.99 per gallon. That is a very good price and I would like to use it if possible. What would be the worst case scenario if I used the Dexron III? How long and how many miles could I safely use it?

Once again, thanks in advance for your help.

Kent,

My recommendation is to go with TranSynd (or another one of the approved TES-295 fluids). I wrote the specification and approved all the products. You can easily do 100,000 miles on it in your HT746. On DEXRON-III products, I'd only recommend 25,000 miles max. In either case, you should be doing oil analysis (which I can do for you). Send me a PM and I'll give you my cell phone number and we can discuss this.

PS: There are no longer any approved DEXRON products on the market. That specification has been obsolete for 5 years so I wouldn't recommend it at all since who knows what goes into them these days.

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #15 – June 15, 2011, 05:04:08 pm

Tom,

Just read your post. Sure would be nice to go 100K plus!

Please address the Allison bulletin remark about any change to Transyn not meeting specs, even if the torque converter has been partially siphoned out until a followup change is done.

I just worry about spending the cash and then having to do it again. Any way around this?

Nice to have your input on the forum.

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #16 – June 16, 2011, 04:48:01 am

Pierce, It is very simple, everyone knows that if you do not drive it, it will last for ever, not eating your money in repairs or needed service, it is all your choice.
Unlike the fire dept where everything is free, here you have to pay the piper or keep cheaping out ?

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #17 – June 16, 2011, 04:10:13 pm

Penny Wise is very often Pound Foolish. Go with the TranSynd (or approved equivalent) and get rid of the other stuff. It really IS that simple.

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #18 – June 16, 2011, 09:33:49 pm

Dave,

I think you may have not caught my point. I'm not worried about spending the money. My worry is if I change to TranSynd and can't replace ALL the old fluid and according to the factory bulletin, this will not meet Allison specs, what risk am I taking driving and how long should I go until the next change to bring it into Allison specs? Am I in a gray area and what are the downside possibilities until it is ALL TransSynd? I just wanted to hear the factory answer (or retired factory answer).

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #19 – June 16, 2011, 10:20:53 pm

Quote from: amos.harrison – June 14, 2011, 07:58:10 am

Tom,

Could you comment on the time-based requirement for Transynd changes for those of us that don't accumulate a lot of miles per year? Also, what's behind the severe service designation for all Allison trannys with a retarder? Can we consider longer change intervals if we limit trans temps to some max level?

Amos,
Time based changes only apply if you are not doing oil analysis. Oil analysis takes precedent over both distance based and time based recommended change intervals. Allison places "Severe Duty" restrictions on all retarder applications because the retarder absorbs braking energy and transfers it to the fluid as heat. Therefore, sump temps are higher and oxidation life of the oil is shorter. Oil analysis picks up viscosity change, wear metals, oxidation state, and contamination. This is all that is needed to extend drain intervals. Sorry, there have been no test studies so there are currently no rules for sump temp vs. drain interval. You either do time or distance based "default" intervals or you do oil analysis and run until the analysis says to change the fluid.

Make sense

? You can save a "ton" of money doing oil analysis.

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #20 – June 16, 2011, 10:28:17 pm

Quote from: Pierce & Gaylie Stewart – June 16, 2011, 09:33:49 pm

Dave,

I think you may have not caught my point. I'm not worried about spending the money. My worry is if I change to TranSynd and can't replace ALL the old fluid and according to the factory bulletin, this will not meet Allison specs, what risk am I taking driving and how long should I go until the next change to bring it into Allison specs? Am I in a gray area and what are the downside possibilities until it is ALL TransSynd? I just wanted to hear the factory answer (or retired factory answer).

Dave,

You just need to do a double drain and refill. That will get you around 90% TranSynd and that's what Allison wants you to do for the maximum drain intervals.
Here's what I mean by a double drain and refill. Drain the old fluid, refill with TranSynd, drive around for 1/2 hour (approx.) just until the fluid is warmed up and circulated through the torque converter and cooling system. Then, drain again, change the filters and refill with TranSynd. At this point you're good to go for the maximum recommended drain intervals. If you really want to maximize the utility you get from TranSynd (miles/dollar), start doing oil analysis and change based on fluid condition instead of the recommended change intervals. Allison publishes this but it's in the small print. I know because I wrote the small print.

Thanks !!

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #21 – June 17, 2011, 12:46:24 am

Tom,

Thanks for the definitive answer about the double drain and refill. Your last two posts should clear up any questions that most of us will have. Covered it well but I guess that was your job. Now to get you in a Foretravel.

Thank you !!

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #22 – June 17, 2011, 01:04:41 am

Tom,

On another transmission question. Is it possible for a Allison HT746 not to go into lockup? If it did not, would this result in elevated transmission temperatures? Would an owner be able to see this by reading the code by pressing the transmission switch under the flip up dash and reading the flashes from the bulb or would a specialized reader be required to retrieve stored codes? Most likely culprit?

Thanks in advance.

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #23 – June 17, 2011, 08:37:55 am

As far as switching from Dexron to Transynd (which I did many years ago), I have a slightly different procedure than Tom suggests.

With the first change using Transynd, stick with the same drain interval as you did with Dexron. After the NEXT change, then you can go by the Transynd change interval/change interval based on fluid tests.

At least I can't justify two changes within a few miles. You certainly are "covered" using the Dexron change interval with the 80% Transynd/20% Dexron you have after the first change (due to fluid in the torque converter, cooler and lines to cooler that do not drain).

Brett

Re: Use of SAE 15W40 motor oil in Allison HT746

Reply #24 – June 17, 2011, 12:00:10 pm

Brett,
I'm inclined to go with your proceedure of driving the TranSynd the time allowed for the Dexron insofar as cost effectiveness goes. Tom can chime in if this is not the Allison recomendation.

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