Changed the PCM transmission fluid today and...

[IDBoating]

Some here may remember that I received a brand new PCM transmission under warranty last Fall (thanks, PCM! ). I just changed it at the 25 hour point as required by PCM (every 100 hours/12 months thereafter). The old fluid looked perfect, no signs of contamination or particulates at all.

However, just like when I changed the fluid on my original transmission, I could only extract about 1/2 a quart. The manual says it takes two quarts (!!!), yet both times I've changed it my MityVac 7400 has sucked it dry at ~16 ounces. Another ~16 ounces brings it right up to the full line on its dipstick, even after taking it out for a short test drive with shifts into forward and reverse (again per the manual).

I probed around with the MityVac's hose. The first time I found a small pocket of additional fluid, but after that I got nothing but air.

If I'm not getting all of the fluid out, I'm wondering if I should change it more often - say with every engine oil change at 50 hours. That would be 2X as often as required, but Dexron III is cheap compared to transmissions.

I know some fluid is in the intercooler and hoses, but PCM would have no way to know how long the hoses are so I presume their "two quarts" means the amount in the transmission housing itself.

Anyone else service their own PCM 1:1 transmissions? How much fluid do you get out?

[dom w. forte]

Whats the size of the hose you are sticking into trans to extract the fluid, we use a small plastic type tube about .25 dia. to get to the bottom.

[IDBoating]

Yep, about that size. It's the smallest plastic hose that came with the 7400 that Kevin recommended. If I poke it around a bit I can "get deeper" and find a pocket or two, but I've done that each time and only get about 16 ounces. After that all I get is air.

How much do you get out?

[dingleberry]

When I serviced mine for the first time over the winter, I ran into the same thing. Used a hand pump to suck it out into just an oil collection pan, so I didn't realize how little I managed to get out. Seemed like not as much as I expected, but I finally gave up after trying to poke around with the hose for about 15 mins.

When I went to put the new ATF in, it over filled with less than one quart. So I just repeated the process a couple of times, figuring at least it would eventually replace almost all the old ATF (plus, the old stuff had looked pretty good, anyway). Then just filled it to the correct level and called it done. Been working fine this summer so far.

[IDBoating]

Yeah, as mentioned above I think I'll just start changing it with every oil change. That will be twice as often as required, making up in some degree for the fact that I'm not changing all of it.

Unless I AM changing all of it. I'm still interested to hear how much Dom gets out of the transmissions when his shop does a service. If they get more, I'm anxious to hear how!