Yet another tranny fluid change question

[epa1775]

I've been reading alot of the old posts about changing tranny fluid and my question is this. It seems like there are multiple ways to do it. I was planning on just draining it from the plug and then filling it back it up. (Have 9 qts of Amsoil). Is this sufficient? I've also read where you can pull out one of the cooler lines and flush it out while running the truck. Thanks for the help. This is my first diesel. My old man posts on here though I'm not sure what his user ID is. Thanks for the help.

Pete

[ANXIOUS-SUBMAN]

If you only drain the pan you won't get much fluid out. I do that about every other oil change and it only takes less than three quarts to top the trany off again. You don't have a signature so we don't know which trany you have.

[epa1775]

I have a 2002 GMC Sierra 2500 HD truck. Only three quarts huh? Guess I'll be pulling cooler lines.

Pete

[jbplock]

Pete,

The spec for an Allison drain & refill using the plug on the OEM pan is 7.4qts. If you do the flush by removing the cooler return line you will need more fluid .. I used approx 14 qts when switching mine to 100% M1-ATF. I later installed the deep pan which adds another 3.2 qts.

Try searching the forum for more info...

:)

[Tsckey]

I did it the lazy man's way and just drained and refilled (filter, too, of course). After two changes I'm getting close to 100% synthetic. If I'd had an extra body and a bit more guts I'd have tried pulling the cooler lines. But, my ability to screw things up is pretty well advanced. Even I can unscrew a drain plug and put it back without hurting anything.

TC

[Mr. D]

When I drained the pan of my '02 Allison I bought a large, heavy plastic food container with graduated markings at Smart and Final so I could be sure exactly the amount of ATF that came out. It wasn't what I had been told, it was more! Then I replaced that exact amount with synthetic and checked the dip stick afterwards to be sure.

[jbplock]

...I bought a large, heavy plastic food container with graduated markings ... so I could be sure exactly the amount of ATF that came out. It wasn't what I had been told, it was more! ...

Mr. D,
I had a similar experience .. I also used one of those plastic food containers (stolen from my wife) but being an ultra-anal engineer type, :rolleyes: I checked the graudations first by pouring in 1qt of water at a time from a "calibrated" 1 qt oil bottle. I found the grauduations on the big container were way off :eek: .. so I put my own marks on it.. not that it made much difference but I felt better ... :)