A3 Transmission Fluid Questions

[glcaines]

I now have the official word from Castrol and Allison on the compatibility of TranSynd and motor oil. I have heard concerns that to switch to TranSynd, that it is better to switch to Dexron III first and then go to TranSynd. I plan on replacing the motor oil in my Allison 1545P with TranSynd. Here is what I found out directly from Castrol Technical Service.

Question for Castrol:
I have an Allison 1545P transmission with 10w-30w
motor oil in it and would like to convert to TranSynd fluid. The military uses motor oil instead of TM fluid. I have been told that motor oil is not compatible with TranSynd and that I should instead convert to Dexron III by draining and filling. Can I safely drain and fill 2 - 3 times with TranSynd to purge the system of motor oil? I'm concerned about any potential compatibility problems between motor oil and TranSynd.


Answer:
Thank you for contacting Castrol,
Castrol Transynd will be compatible with motor oil; however it will require several transmission fluid flushes to purge the system of motor oil.
Castrol Consumer Relations

I still most likely will purge with Dexron III several times first just to get rid of the motor oil with a less expensive fluid. I also contacted Allison by telephone (very difficult) and they told me basically the same thing as Castrol. Allison also told me that there is absolutely no problem with using Dexron III - it simply needs to be changed more often. Allison told me that the transmission will work just as well with Dexron III as TranSynd, but to be very careful since Dexron III is no longer certified by GM. I was also warned very strongly NOT to use Dexron VI as it will eat up the seals in a 1545P transmission.

 

[glcaines]

Well, I finally got around to purging the motor oil from the Allison transmission in my A3. I bought five gallons of Dexron III from NAPA (NAPA Brand). Before I started, I drove the truck 10 miles to make sure the fluid was thoroughly hot. I drained the pan with the big drain plug, and refilled with Dexron III. I then drove about 8 miles, and repeated the process. I did this five times. The fifth time, I didn't drain. I also replaced the external filter. One note here: the external filter was barely screwed on. It was very loose, but amazingly, it was not leaking. I have about one quart left of the five gallons of Dexron III I started with. I should note that when I drained the motor oil, it was as clean looking as if it had just come from the can. My truck only has about 4K miles on it now, so unless something is slipping in the transmission, the oil should look clean.

Man, what a difference in the way the transmission operates! A lot of people on SS have made the switch in their A3s and have sung the praises of dumping the motor oil. I'm now definitely in that camp. The transmission shifts much more smoothly, both up and down. Previously, the shifting seemed to hesitate and then the truck would lunge when the transmission shifted. No more - it now shifts smooth as silk. I would recommend everyone to make the switch. In my opinion, the military was foolish for using motor oil, although I understand their reasoning.

I also have five gallons of TranSynd that I planned to switch to after purging the motor oil with Dexron III. I'm now having second thoughts. I may just keep the Dexron III in the transmission and sell my bucket of TranSynd. Perhaps it's just because I'm so tired from working on my truck about 12 hours straight today.

 

[goodguyzy]

good post, im planning on doing the same thing. Thats after i disconnect the CTIS. Call me lame but i plan on leaving the rock guards in place and "shaving" the counter weight to equal the guard.

 

[renovate7]

I have one more drain and refill to do and then I'll be running on Dex III. On this truck also the motor oil that came out on the first drain looked and smelled like brand new.... I like your description about it hesitating and then lunging as it changed gears on motor oil, thats exactly how I would describe it...There's an easier way to disconnect the CTIS and keep everything in place for accuracy and future reuse. I just pulled the hose that runs from the lug to the CTIS valve on the wheel and put a plug in each. It's all still there and can be reconnected by putting the hose back in.

 

[goodguyzy]

that's a good idea on the CTIS, however i want to take out valves and weigh each cover,nut,etc and match that on the counter weight. Ive got some really bad bounce on some of them and think that's a good place to start.

 

[glcaines]

that's a good idea on the CTIS, however i want to take out valves and weigh each cover,nut,etc and match that on the counter weight. Ive got some really bad bounce on some of them and think that's a good place to start.

I've been running one wheel with all CTIS components installed, sans the rock guard. I do have the extra nuts installed that secures the rock guard. I haven't noticed any difference in the way it runs. I capped the hollow lug as well, and screwed valve with bushing into the valve stem to hold air. Hopefully, I will have a new wheel valve shortly.

 

[renovate7]

I added lead shims behind the existing weight to balance the tire with all the CTIS stuff still in place.. Makes a world of difference.

 

[glcaines]

I added lead shims behind the existing weight to balance the tire with all the CTIS stuff still in place.. Makes a world of difference.

I would be careful using lead shims behind the weight. Lead flows very easily under pressure. When the nut is torqued down, you can get the proper torque setting, but as the lead is squeazed out, the torque setting will relax, possibly causing loss of air at the o-ring seal in that part of the wheel. However, that is a neat looking job.

 

[goodguyzy]

i would like to take all the CTIS components and weigh them to see exactly what they are to see if the counter weight equals. I would assume AM general did this in the design, but at work i find engineers screw up all the time.

 

[Floridianson]

Kinda got off topic with the CTIS stuff guys.
After reading all the posted how does this sound. Drain the pan and fill the pan with new Dextron 3 or equ. Take off the spin on filter. Have soldier # two watch the 5 gal. buckett that is under the filter and stop the motor when it changes color or an amount you feel is is close to 2/3 what was in the pan. Blow out the return line from the filter to trans. with air. Drain the pan again. Fill with Dextron 3 or equ. again and change spin on filter.. Run like this for a dertermand amount of time or miles. Say 100 miles. Then the last change with Dextron or equ. and trans pan filter plus spin on?

The price of the oil is not a concern for me here but to get a good change out.

 

[Sutphensvc]

Ok, being an Allison tech and working on a couple A3's, dextron III or transyn is ok, using the napa hyd fluid not so good.

If you drain down the pan, pull the return and feed line line from the cooler and with them not hooked to the trans, blow air in reverse direction thru the cooler lines, about 25-35 PSI will do.

After all the fluid is out(or as much as possible), hook the lines back up and put in the fluid, only fill to the top of the fill line. Start truck for 2-3 mins then shut down, add to fill line again. Run truck till fluid hot and add again until normal fluid level is where it should be.

Transynd and dextron III shouldn't be mixed in any large fashion, but a little is ok.

 

[Floridianson]

My thought here was to suck up the new fluid and spin the old out of the TC.
When changing out the old I don't see how it would hurt to over fill the pan till the dip stick is full. As soon as I start it and the oil starts to flow out the spin on filter housing and the pan will be down below the need to add line fast.
How many Qts. does the TC hold?

I rember the old Dodge/Chrysler you could drain the TC with the plug they had in it.

 

[Sutphensvc]

If I remember the tc holds about 8 quarts. If you wanted to get really crazy, find a mom and POP tranny shop, and have them do a fluid exchange. A little left in the tc won't hurt much, we never get it all when we do pm's.

Let me pull my books in the morning, to see what Allison says is acceptable amount of cross.

 

[goodguyzy]

An A3 thread of topic? welcome to the A3 world, every thread is a jumbled mess. Until we get our own forum, that's how it will be

 

[Rustygears]

How can the Napa tranny/hyd fluid be 'not so good'? It is rated dex III, GL-4, CAT ratings, C-4, etc. Napa is a large & reputable company and if the oil didn't meet OEM specs, they wouldn't claim it and wouldn't risk major fleet lawsuits printing it in their catalogs, literature and containers.

I can assume the poster claiming 'not so good' has a PhD in both analytical chemistry and mechanical engineering as well as a complete lab where a thorough analysis has been performed to arrive at that conclusion? Or is it an opinion based upon rumor and impressions?

I hate it when opinions are presented as facts. We are all looking for guidance based upon actual experience and facts.

 

[mktopside]

How can the Napa tranny/hyd fluid be 'not so good'? It is rated dex III, GL-4, CAT ratings, C-4, etc. Napa is a large & reputable company and if the oil didn't meet OEM specs, they wouldn't claim it and wouldn't risk major fleet lawsuits printing it in their catalogs, literature and containers.

I can assume the poster claiming 'not so good' has a PhD in both analytical chemistry and mechanical engineering as well as a complete lab where a thorough analysis has been performed to arrive at that conclusion? Or is it an opinion based upon rumor and impressions?

I hate it when opinions are presented as facts. We are all looking for guidance based upon actual experience and facts.

"Kid #3: My Mommy says smoking kills.
Nick Naylor: Oh, is your Mommy a doctor?
Kid #3: No.
Nick Naylor: A scientific researcher of some kind?
Kid #3: No.
Nick Naylor: Well, then she's hardly a credible expert, is she? "

 

[Sutphensvc]

It is rated with the correct friction modifiers, and at running temp hold nice on the clutches, but if you take off cold without running the tranny up to about 100 degrees to thin it out, it will allow premature wear.

I am not saying don't use it, its just not recommended. Dextron and Transynd have a thinner viscous level when cold.

Valvoline has a multigrade atf that says ok for Ford SP, but has torn up a countless amount of torqueshift trannys.

I am not trying to be a know-it-all or trying to say can't or don't, just trying to share knowledge from yrs of work and training have shown myself.

 

[Rustygears]

"thinner viscous level" => "lower viscosity" ? (No such thing as 'viscous level')
"Dextron" => Dexron? (No such thing as 'Dextron')

I think 10w40 (as used by the Army) is much more viscous than the industrial Napa transmission fluid referenced. Dexron III has the same viscosity as the referenced Napa fluid. That is why it carries the Dexron III certification and has for many years.

 

[Sutphensvc]

Yes, I didn't pay attention to my "smart" phones autocorrect, sorry about any confusion with the terms.

Allison, does approve 40w for the non TCM transmissions(computer controlled), that being said, some industrial World type Allisons also allow for 40w.

 

[glcaines]

I think 10w40 (as used by the Army) is much more viscous than the industrial Napa transmission fluid referenced. .

I'm convinced that lower viscosity is the main reason the Allison transmission shifts much more smoothly and quicker with the ATF than the motor oil. I drove my A3 again yesterday and I am amazed at how much better the transmission feels. My transmission is the 1545, which locks up, and the lock up function is also much smoother than with the motor oil installed. I think anyone with an A3 that still has motor oil installed and then drove one with ATF, would immediately be convinced to change out the fluid.