Former Allison Transmission Fluids Engineer

[JoeT]

Tom, thanks so much for you contribution to this forum.
My question is:
I have some Transynd left from my last fluid change three years ago. I'm due to change my filters. Will the left over Transynd still be good to replace the lost fluid when I change the filters? I don't know the shelf life of Transynd that has been opened.

[hzjcm8]

Quote:

Originally Posted by JoeT Tom, thanks so much for you contribution to this forum. My question is: I have some Transynd left from my last fluid change three years ago. I'm due to change my filters. Will the left over Transynd still be good to replace the lost fluid when I change the filters? I don't know the shelf life of Transynd that has been opened.

Joe,

No problem. The shelf life is at least 10 years.

Happy motoring !!!

[Steve Ownby]

Tom,

Thanks for your generous input of time and expertise on this forum.

I have a fluid related question about heat rejection but this may not be in your field. On a couple of other forums that I participate in, there have been a number of instances of the transmission fluid cooler, which is internal to the engine radiator and immersed in engine coolant, failing. When it fails both the engine cooling system and the transmission are cross contaminated. This appears to be catastrophic to the transmission & requires a complete rebuild.

My question is, can a transmission cooler external to the radiator provide enough cooling capacity without being so big that it's not practical? The coolant immersed design appears to be common in the diesel pusher business but appears to be a serious weakness.

Thanks again,

[kbeseman]

Mr. Transynd,
Have a '03 coach w/ a Allison 3000, trany oil changed at 35K w/ Transynd, now have 80K mi. Is it OK to go back to the Dextron or what?
Thanks,

[oemtech]

Quote:

Originally Posted by kbeseman Mr. Transynd, Have a '03 coach w/ a Allison 3000, trany oil changed at 35K w/ Transynd, now have 80K mi. Is it OK to go back to the Dextron or what? Thanks,

I would have it tested just for grins.. But, me I would do new filter/filters and new Transynd fluid.

[AFChap]

Quote:

Have a '03 coach w/ a Allison 3000, trany oil changed at 35K w/ Transynd, now have 80K mi. Is it OK to go back to the Dextron or what?

Don't see why you could not go back to Dexron. My Allison has a bit over 60k on it. I don't use synthetics as I see no advantage to them for our use ...and the only vehicle I have owned that had sythentics in it had a total rear end failure way earlier than any dyno-lubed vehicle I have ever owned.

[hzjcm8]

Quote:

Originally Posted by Steve Ownby Tom, Thanks for your generous input of time and expertise on this forum. I have a fluid related question about heat rejection but this may not be in your field. On a couple of other forums that I participate in, there have been a number of instances of the transmission fluid cooler, which is internal to the engine radiator and immersed in engine coolant, failing. When it fails both the engine cooling system and the transmission are cross contaminated. This appears to be catastrophic to the transmission & requires a complete rebuild. My question is, can a transmission cooler external to the radiator provide enough cooling capacity without being so big that it's not practical? The coolant immersed design appears to be common in the diesel pusher business but appears to be a serious weakness. Thanks again,

Steve,

You're right, it's not really in my field of study. But, I don't see why you couldn't do it. It would definitely need an independent fan though. I know that at one time, Allison had an "Integral Cooler" design but I'm not sure of the performance.

Sorry, but that's all I know about this subject.

[hzjcm8]

Quote:

Originally Posted by kbeseman Mr. Transynd, Have a '03 coach w/ a Allison 3000, trany oil changed at 35K w/ Transynd, now have 80K mi. Is it OK to go back to the Dextron or what? Thanks,

Kbeseman,

There's no problem switching back and forth between TranSynd and DEXRON-III (if you can find one). However, I'm not sure why you'd want to do that given the long drain intervals and good chemical and physical stability of TranSynd. So, why do you want to switch back?

Also, what makes you think you have to change the fluid at all? The TranSynd should be good for 300,000 miles.

[hzjcm8]

Quote:

Originally Posted by AFChap Don't see why you could not go back to Dexron. My Allison has a bit over 60k on it. I don't use synthetics as I see no advantage to them for our use ...and the only vehicle I have owned that had sythentics in it had a total rear end failure way earlier than any dyno-lubed vehicle I have ever owned.

AFChap,

What do you pay for a transmission fluid change? How often do you change the fluid? Are you doing oil analysis to determine end of fluid life? I can tell you that not all synthetics are good. Some will still shear down (lose viscosity over time). I personally tested TranSynd for 10 years in city buses with retarders (Allison B400R and B500R transmissions). We also ran it in a bus for 100,000 miles and then ran a 2000 hour durability on an Allison 1000 Series transmission with no problems using the used TranSynd.

It's pretty much "bullet proof". With the ultra-long life and stability, I'm not sure why you're not using it even at the high price. The price is easily offset by the cost of the oil changes over the life of the vehicle.

Please keep in mind that I'm good with you doing whatever you want. Either fluid is OK (TES-389/DEXRON-IIIH or TES-295) ..... it's just a matter of fluid life and corresponding drain intervals.

[Mr_D]

Quote:

Originally Posted by hzjcm8 I think we changed over to TranSynd in the factory in January of 1999. Before that we used DEXRON-III GM factory fill from Petro-Canada.

The problem is that when the transmission was installed in a chassis the builder may have used Dexron to refill it. That's what happened to my 2000 and 2002 Newmar Dutch Stars. Then I had to go through the two drain/filter change/refill cycle.

[Route 66]

Quote:

Originally Posted by Mr_D The problem is that when the transmission was installed in a chassis the builder may have used Dexron to refill it. That's what happened to my 2000 and 2002 Newmar Dutch Stars. Then I had to go through the two drain/filter change/refill cycle.

Correct. Don't know why they would do that, but they did.

[AFChap]

Quote:

What do you pay for a transmission fluid change? How often do you change the fluid? Are you doing oil analysis to determine end of fluid life?

My records say 2 year change interval (anywhere from 8-22k miles) at cost $240-$290. I am not doing any oil analysys.

Quote:

Transynd ...It's pretty much "bullet proof". With the ultra-long life and stability, I'm not sure why you're not using it even at the high price.

My '02 Spartan chassis came with DexronIII. If it came with Transynd I most likely would be using it. As indicated before, my experience with synthetics (very limited, yes) has not been good. On the other hand, dino oils have served me very well.

[monarchman53]

My '03 Allison 1000 has 25000 miles on it and I would like to change it over to TranSynd. I keep hearing about "the two change change". I understand the principal but am not sure of the process. How far do I need to drive it after the initial change before draining and filling the second time. Also do I need to use two filters (one for each change) or one? If one, do I change at first or second fill?
Thanks,
Rod

[DAN L]

Quote:

Originally Posted by monarchman53 My '03 Allison 1000 has 25000 miles on it and I would like to change it over to TranSynd. I keep hearing about "the two change change". I understand the principal but am not sure of the process. How far do I need to drive it after the initial change before draining and filling the second time. Also do I need to use two filters (one for each change) or one? If one, do I change at first or second fill? Thanks, Rod

do you store your moho in the winter?
i left my moho sit unstarted for a couple of months. most of the torque converter oil drained into the transmission pan.
my alli 1000 transmission holds 14.1 quarts. i drained 13.5 quarts including the filter. i refilled with 13.5 quarts of amsoil tes 295 fluid. that is a 95.7% fluid change which is good enough for me.
if you were to drain 10 qts, refill with tes 295 fluid, then drain again imho you would have 71% the first time and about a 95% fluid change the second time at considerable more expense.
don't forget to take the magnet off of the old filter and reinstall it on the new filter.