Transmission Fluid chg - Time vs. Miliage

[Paul T]

My Workhorse Maintenance Schedule calls for transmission filter/fluid change at 50,000 miles with no time zone mentioned.
My Allison’s Operating Manual says 50,000 miles or 24 months.
Of course I’m just reading it for the first time while thinking I had a long time to go getting to 50,000, And now am a bit perplexed that the Workhorse schedule led me astray (Even though I think 24 months for the TranSynd fluid is a bit conservative.) Have all you folks really swapped out transmission fluid/filter at 24 months? I did the 5000 mile trany filter change and haven't given it a thought until now and its running great.
I'm never going to get to retire!

[TWOSHEA]

Paul T, No need to Being that you have an '06 MH you are ready for a transmission change. Not because of the 50'000 miles, but because you are at the four year change date for Trans Syn. We have an '03 Bounder that I had switched to Trans Syn Sept. 18, '07.. I had it done at Atlantic Detroit Diesel Allison in Latham, NY.. I am good for four years or 4000 hours (two years to go ) Change the Trans Syn every four years You can find Atlantic Detroit Diesel Allison I venture to say in all states... After all it is an Allison Trans.

[DriVer]

According to Allison:

Depending on the vocation and duty cycle, extended drain interval guidelines for TranSynd™ are up to 300,000 miles/48 months/6,000 hours for general duty and up to 150,000 miles/48 months/6,000 hours for severe duty.

A motorhome's duty cycle is rated as severe duty.

[Paul T]

I was hoping for replies like DriVer and TWOSHEA have provided but would like to see it in writing. I assume a perusal of the Allison web site is a good place to start. Thanks guys,

[TandW]

Pay now or pay later. Insurance is cheaper than to have to react to extensive repairs at some inopportune time. Say DriVer, do you know whether or not water is held in solution by any or all types of tranny juice? Thanks!

[DriVer]

Quote:

Originally Posted by TandW Say DriVer, do you know whether or not water is held in solution by any or all types of tranny juice? Thanks!

Chief, That's one heck of a good question and I might approach an Allison Service Center with the same question. I know there will be the possibility for moisture to enter all of the systems on the chassis however the effects on each are difficult to document. Exposure length, environment and operational cycles will largely affect the percentage I would expect.

Thanks for the question.

[TWOSHEA]

Paul T, I led you in the right direction for service as it would apply to the NE corridor of the US. Go to www.allisontransmission.com and click on locations. (upper right hand corner of home page) Click your way through the sight bringing you to which ever State you want to locate a service center in. Give them a call and they will answer all your questions.

[TrekPR]

As the transmission is not a closed system I would think water would evaporate when the transmission is brought up to operating temperature. If you had a large amount would it not show up similar to water in the engine oil?

[JCM]

The problem there is that the transmission never gets that hot - in comparison to the motor. I don’t think that the water would be "boiled" off.

[TrekPR]

I don't want to be argumentative and I don't really know how water will react in this instance but water does not have to boil to evaporate.

[Paul and Sue]

I don't know when your warranty runs out, but one rule I live by is, I always change the trans oil on cars, trucks, motorhomes just before the warranty runs out. That way if anything is wrong in there like metal, water they can find it and fix it before your warranty runs out. I have done this for the last 30 years and it paid off only once, my 1999 ford V-10 motorhome had a one inch long metal band which was part of the retainer ring. They replaced the trans with one month of warranty left.

[TandW]

Not all the water that enters a gas tank comes from the fuel island. As a less than full tank experiences changes in surrounding temperature, the vapor pressure can sometimes be insufficient to prevent moisture-laden ambient air from entering the tank. Once this humidity enters the tanks it condenses into water. We know that gas does not mix with water. Take brake fluid which is a high temp hydraulic fluid. We have been told that it will hold water in suspension. Thus we do not have to fear frozen brake lines, as with air brakes. Then we have ATF. A hydraulic fluid which is expected to work in below zero environments. I suspect it probably has some of the same water dissolving properties as brake fluid. But then, maybe not. But I do expect that water does enter the transmission case with changes in operating conditions, parameters or the environment. I changed out some contaminated ATF in my AAPB resorvoir. The fluid was opaque and pink, not the normal clear red color. After some time on the shelf the water and ATF still had not separated. I don't know; this is just an observation. Good luck!!!