So I was thinking about what a mess and hassle it is to drop the pan and all, and I was thinking maybe there's a better way.
Would it be possible to just disconnect the line running to the cooler and let the fluid go into some kind of clear container (2 liter bottle maybe?) and replace whatever comes out with fresh fluid as I go? I suppose this could be a long way to do it if the fluid flows through there at a slow pace, but I don't see why this wouldn't work.
Any pros or cons from y'all??
By the way, I have a Ram D250, 89 model, 2wd, 3spd auto.

 

that would not drain the fluid out of the transmision. all you would do is drain the oil out of the the cooler and the line. you are better off to take the oilpan off and do an oilchange. then you can see it there is a problem with your transmision. like metal debris in the bottom of your oilpan. plus then you can make sure the oil pickup is clear.

 

Can't change the filter very well unless you drop the pan.

 

Good points- thanks for the cons. Any pros? I'm a little confused about how you say that it would only be removing the oil from the cooler- doesn't the oil flow through the cooler? I'm talking about doing this with the engine running so that the fluid would flow. Isn't that how it works? The fluid goes into the cooler on one side and back into the tranny on the other side. Right?
You're totally correct on the filter point, though. I should probably do the whole nine yards, and then an annual fluid change. This truck only sees about 8 to 10 thousand miles per year.

 

if you do that with your engine running you will probably fu*% your transmision because you will be running it without fluid. if you don't want to deal with the mess you could take it to a shop for them to do a transmision flush. it would probably cost $100

 

well i dont recomment this. but i emptied my transmission in a very simlar fashion. i had the front end up on jackstands for a couple days, and i guess one of the cooler lines was leaky. It was wet and snowy outside so i didnt notice it all drained out. When i put the truck back onto the road it was running like a bag and i didnt know why. after 2 weeks i realized i had basically no fluid in the transmission

 

So all the fluid drained out while it was just sitting there? I bet that took a while. My idea about doing it with the engine running was to go about it a quart at a time, a quart out, then a quart in. I know better than to run it dry.

 

you could try jacking up the front end and taking out the driveshaft but you are still better off to do it the propper way and take the oil pan off. its not that messy.

 

A transmission holds 8 quarts. 1 out 1 in and you still have 8 quarts of contaminated fluid that is just slightly less contaminated by 12.5% and you still have a dirty filter and whatever sludge is left in the pan. 1 more out and 1 more in cleans the oil by even less than 12.5% because 1/8 of the second quart drained was new oil you just added. Every time you do this the benefit continues to drop. Even when you drop the pan and change the filter you only reduce the contaminated fluid by 50% because you only drain 4 quarts by dropping the pan. The filter change and the sludge that is cleaned out of the bottom of the pan and the diagnostics gained by what is in that sludge are the the best reasons for dropping the pan.
If you want to stop a lot of the mess they make a drain plug you can install in the pan. I have one and it is great. It is just like draining the engine oil.

 

* let me clarify, when i say "all" of the fluid leaked out i really mean that it was no longer showing on the dipstick. i think i had to add four or five liters (about four on five quarts) into my A727, i dont know what the capacities are on all the transmissions.

I had to drill and tap a new oil pan plug when my brother ruined one on his blazer, it wasnt that hard, so i think SEAL is on to something with making one for the tranny...