I'm thinking about changing from the Oil that came in it to Dexron. I've read all the threads below. The book says the capacity is 16 qts to drain and fill, 20 qts if dry (installing a rebuilt tranny?) and 22 qts total (includes cooler and lines?). I liked the idea of removing the return line from the cooler and refilling as it runs out to get it all, including the torque converter. However, the transmission fill tube runs into the pan at the very bottom. The outlet to and return line from the cooler are at the top. How can I be sure I'm getting it all and the new fluid isn't just being put into the bottom and then taking a short route and being pushed out at the top, engine running, leaving oil in the tranny? If I drain and fill, getting 75%, run the truck, then drain and fill again, leaving 6% of the original fluid in the tranny, is this OK? If the engine oil and Dexron are compatible I think that would be easiest, although expensive with Dexron III being $10 a gallon. We have a local Allison Dealer here but I've found getting the right info from dealers isn't always easy or possible. Thoughts from the board please.
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A3 Transmission Fluid Questions
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mktopside
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DEXIII is cheap, just buy 7 gallons instead of 5 and drain and fill it and extra time to get the rest out. It's not rocket science, you just want clean fluid in there.
Remember if you have trouble filling the trans, you likely have a clogged vent line. The vent lines are on the back of the cab, and run up to the top then slightly back down. Blow some compressed air through the hose if it won't fill.
shovelheadmike
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I agree. The drain and.fill is what I did.
Loganwood
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Me too. I just got 5 gallons in though
glcaines
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I'm going to use the drain and fill with mine as well.
shovelheadmike
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While I was told by the local Allison dealer not to go from.the.motor oil.to.the.transsyn, but.to Dextron3. I believe.it.is.safe.to.then go from.the.Dextron 3 to the Transyn. That is.what my father did on his Monaco motor home. At.which time.Allison did extend his trans warantee.
mktopside
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That's what I had assumed as well. I've got about 1500 miles on the Dex, and I might do the switch to Transynd when I change the engine oil next.
I think I'm going to give Delvac 5w40 synthetic a shot in the engine on the next go around.
Rustygears
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When I brought my A3 home, I immediately bought a pail of Napa hydraulic fluid (NHF 85-405 Premium Heavy Duty Tractor Hydraulic & Transmission Fluid GL-4), which carries a Dexron III rating and surpasses it with the GL-4 rating. This oil is a great price and comes in bulk 5 gal pails. I wasn't able to flush, so I changed filters and filled with the Napa fluid, giving me a 43% Dex, 57% 10w-40 MO mix. I only today was able to actually drive it, getting the new fluid circulating through the circuits for all 4 gears. What a difference! The shifts are better, the temperature has dropped considerably. Next weekend I will change the trans oil again, which should put me at about 80% Dex. It will be interesting to see if I can tell any additional difference in operation.body, div, table, thead, tbody, tfoot, tr, th, td, p { font-family: "Arial"; font-size: x-small; }
lonegunman
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I swapped mine to Dex before driving it cross country. Temps dropped easily 20 degrees and shifting got a lot better. Best idea ever.
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Talked to a Allison mechanic and his thoughts were to run the motor oil and not change out to ATF because it is going to wash out a lot of nasty stuff and could cause problems. He thought I should run it till it need R&R then change out. Guess we will see if anyone has any problems along these lines after change out. I do like the idea of a change out though.
Got lots of good info here...I drained the fluid to change it and only got 8 qts, book says it should be 16. Went to the Allison sight and found out they used 2 pans, one 3.8" high that uses 9 qts per change and one that is 5.3" high and uses 16 qts. I have the 3.8". The C4 fluids which include several weights of motor oil are for severe duty and off road. They are only to be used at 5 degrees and higher. The Dex III is for light duty and highway and is good to minus 22. NAPA had several 5 gallon buckets of different products that would work including DexIII and various tractor and industrial fluids. Some were C3/C4 compatible, others Dex III. Some mentioned various makers including Allison on their labels. I also changed the filter, NAPA #1268. The Allison sight also said they made 5602 of these AT1545 transmissions...So it looks like I changed 8 of 15 qts. I'm going to run this a bit and change everything again. Because it only took 2 gallons and I bought 8 I may do it a third time. I understand about changing types of fluids and the problems it can cause to a piece of equipment with a lot of use but this truck only had 3850 miles...I had posted in another thread about people who used motor flush, diesel in a can, in high milage engines. By the time it washed out all the gunk and varnish they had a big drop in oil pressure, not good.
shovelheadmike
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Allison told me that the motor oil will varnish really bad when heated with a little load on the trans and should be removed.ASAP!!!
shovelheadmike
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Yes, the Dextron will.flush stuff out. That is.why we.change.the.filters...
mktopside
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Yea I can't see leaving the motor oil in there with as little miles as these trucks have. Maybe if they had 100,000 miles on them I'd worry about it; but even then any problems caused after the switch were there before and were just being masked by what you were using.
Rustygears
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I agree as well. Motor oil running at tranny temps will varnish - just look at the inside of a valve cover of an old V-8 running 10W-40.
I can't believe the temperature drop I experienced with the 'flush run' when I only had 43% Dex.
The Napa ATF/Hydro oil part number I cited in my earlier post was the correct replacement for DexIII/C4 application and specifically calls out Allison endorsement, as does the GM C4 rating that surpasses the old DexIII rating. This is the same rating that Transynd carries (at a much, much higher price!).
I can't believe the temperature drop I experienced with the 'flush run' when I only had 43% Dex.
The Napa ATF/Hydro oil part number I cited in my earlier post was the correct replacement for DexIII/C4 application and specifically calls out Allison endorsement, as does the GM C4 rating that surpasses the old DexIII rating. This is the same rating that Transynd carries (at a much, much higher price!).
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So you changed out the oil to ATF and replaced the filter so how long are you going to run it before you change out the filter again?
mktopside
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Personally, I plan on changing my trans and fuel filters again on my next oil change just for good measure.
My take on the whole "risk" associated with changing from 15w40 to DexIII is:
"I don't care if something bad happens"
Since switching to DexIII the shifting has been getting smoother and smoother the more I drive it. It shifted so poorly with 15w40, that to me the improvement is worth any real or perceived risk. If the trans takes a dump because of switching to DexIII (as an ASE certified master technician, my professional opinion is it "will not") fine, as the performance with 15w40 would have cause me to go with another transmission in the truck as a top priority. Granted that crap shifting could have been a result of my clogged vent line, but I would have never found out that the vent line was clogged if I hadn't switched to DexIII.
Just my
I tried to blow into each of the three vent lines individually and found two I think are plugged. One of them it felt like a little air was getting thru. Can I disconnect them down below and use compressed air etc to clear them? I'm going to be under the truck later but thought I'd ask here first.
mktopside
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I'm not 100% sure what the other two are, but I think they are for the diffs. I just held onto them while a buddy tugged on the trans vent hose from under the truck, when I felt the one move, I shot some air through it and heard the trans fluid in my funnel go "glug". IIRC it was the middle one, but I don't really remember.
I wouldn't worry about the other hoses feeling plugged, I wouldn't try to force air through them either because there is no where for that air to go if they are for the diffs. If you felt air go through one, it was probably the trans vent, and if you can fill your trans through a funnel without it burping it all over the cab then you are good to go.
When I went to fill mine it didn't immediately occur to me that the trans vent was plugged. I drained it, then went to fill it and it was filling at a rate of 1qt and hour (guess). I let it sit for a while to assure I had enough in there to start the engine, and when I did it drew in most of the fluid in the funnel. I said "Huh, that's weird.... who knows, I'm going to keep filling". So I did.
Eventually the funnel filled back up and wouldn't go down anymore. So I decided to shut the truck off and see what it did.......... Bad idea. As soon as it turned off and huge air bubble shot back up the tube and the funnel, and shot trans fluid all over the cab like a contraption in Willy Wonkas Chocolate factory. I flew out of the cab screaming like a little girl, covered from almost head to toe in trans fluid.
After cleaning up I decided that I should probably check the vent lines, and just chalked up the spill to "Rust proofing".
Mike
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Thought I'd report as I continue this process. I drove about 10 miles today with lots of starts and stops. Tranny got up to 130, it was running 150 but that was also during hotter months. Shifting seems smoother, especially going into 4th. I let it cool for an hour and then changed the fluid again. The oil that was originally in there looked like brand new when it came out, this stuff looked like Cherry Coke. I only got 7 qts out this time. I'm going to do another drive and change it a final time...I checked the 3 vent hoses that go up the back of the cab. The biggest T's under the truck and looks like it goes to each of the brake booster units. One of the small ones goes to the top off the fuel tank. The 3rd went down between the left side of the tranny and the frame rail and was just hanging there. Didn't initially see where it's supposed to go. Guess I'm going to have to dig thru the manuals to find out, not the easiest thing to do.