Please help me out with this. On a closed thread someone said to do the following when changing the fluid in the trans-

"I just drained, refilled with DexIII, and changed the spin on filter but someone on the forum had a good idea that makes sense. That is to drain and refill, then run it in drive with your foot on the brake for exactly 3 minutes then drain again and refill. They claim that gets over 90% of the old fluid out. Your not suppose to power flush an Allison."

Help me understand why ...then run it in drive with your foot on the brake for exactly 3 minutes then drain again and refill.... What am I missing? Why not just drive around for 5 minutes.

I know I'm reading too much into this, but since the thread is closed, I'm wondering why.

Thanks.

I was re-stating a suggestion from another member here. I've not done the math to measure how much of the new fluid transfers out of the pan during those 3 minutes, but it sounded like a logical idea. I'm sorry that I don't know enough to say whether or not this is the best way to change the trans fluid.

I was re-stating a suggestion from another member here. I've not done the math to measure how much of the new fluid transfers out of the pan during those 3 minutes, but it sounded like a logical idea. I'm sorry that I don't know enough to say whether or not this is the best way to change the trans fluid.

Did the other member suggest running the vehicle with the drain plug out? It sounds a risky. Just checking...

Gosh No! I'm sorry for any confusion. The idea was to just drain/fill a second time.

***Replace the drain plug before adding new fluid.:D

Did the other member suggest running the vehicle with the drain plug out? It sounds a risky. Just checking...
sounds like an expensive idea.

Amen. The post didn't seem right but was closed already to comment.

http://www.dieselplace.com/forum/showthread.php?t=231615

I haven't worked on auto tranny's in quite some time but if they haven't changed much, once you refill the pan the first time after dumping it, disconnect the outflow cooling line and start the engine, the new fluid in the pan will get pumped into the torque converter and the old remaining fluid in the converter will get pumped out via the disconnected cooling line into your drain pan. Stop the engine, refill the pan and you should end up with an 80% to 90% oil change. The trick would be the amount of time you run the engine and pump out the fluid. In the old days when old tranny fluid was dark brown and cloudy, you could easily tell when you had reached the optimum point of dumping fluid because the fluid coming out of your drain line would turn from dark brown to bright red.

In this case, if the 1000 holds 13 qts, then I'd pump out about 5 qts and call it good. Button it up and refill to slightly below the hot-full mark.

sounds like an expensive idea.
x2...