transmission fluid change

[pinnacle]

I recently purchased Castrol full Synthetic transmission fluid. I am just going to do a drain ad refill. Since the 02 Yukon has a drain plug in the bottom of the pan this makes it easy. However, the pan drain will only change out 40%-50% of the fluid, I was thinking about pushing some new fluid thru the system and draining it a second time.

My question is: how much fluid will the pump pick up in a minute? How long will it take to pump 3 qts?

I wanted to drain the pan, add 3 to 4 new qts, run it at idle for a few mins and drain it again. If I let it run too long it may mix the fluid too much. But if it doesnt run long enought I will br draining mostly new fluid. Any suggestion other than disconnecting the Cooler?

[Black92LudeSI]

When I had my transmission fluid change they flushed the system. Basically its a machine that circulates the new fluid through the trans. THe fluid as this process is running gets poured out into a bucket. You see the fluid start at this brownish red and eventually turn to a red color being poured out in the bucket. When its red then you know that the new fluid is completely in the trans. This process took a few minutes to do, at least 5 minutes and this machine pumps the fluid through at a good amount of force. In my opinion, if you were to do this your way, it would get out alot of bad fluid but not all of it. I would reccomend for 80bucks getting this done. It only takes about a half hour. They dont drop the pan, they just plug 2 tubes from the machine into 2 different ends of the rubber transmission tubes. It then circulates. I think jiffy lubes have the machines as well as Monroe Muffler

hope this helps

[denalio34ceo]

Dropping the pan is the MOST important thing in the transmission flush. Particles collect in the pan and they have to be taken out. If not, they recirculate through the transmission again with your clean transmission fluid.

[Black92LudeSI]

The flow by the machine pushing the new fluid through will remove the particles(not metal chunks). Small fillings are light enough to move with the fluid. The machine pushes this fluid through at a good amount of speed. Again, your right large metal pieces will sit at the bottom but if this is the case you might as well get a new transmission.

[LOBSENZA]

I am planning to change the transmission fluid in my 2001 Yukon XL Denali and wanted to use full synthetic fluid. Which brand(s) do you recommend?

[LOBSENZA]

One other question, I am planning to drop the pan for the fluid change. I know this only changes a portion of the fluid. Will it hurt to mix synthetic with what they put in at the factory?