transmission flush question
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transmission flush question
I have been reading (mostly here) that there is a thermostat that controls flow to the cooler on the torque shift transmission. That the truck has to be at operating temp and that you might have to heat the Mercron SP to flush correctly.
My question is, Why can't I drain the pan, replace the in trans filter, replace the frame mounted filter, remove the return line, flush like you would any other transmission,(refilling as the return line fills a container) and then shut the whole thing down. remove the cooler lines at the frame mounted filter, and flush the cooler? (15 psi air or a trans cooler flush aerosol). Hook it all back up, run around a bit, top it off.
Would that not replace all the fluid accept what is in the thermostat? (very little)
My question is, Why can't I drain the pan, replace the in trans filter, replace the frame mounted filter, remove the return line, flush like you would any other transmission,(refilling as the return line fills a container) and then shut the whole thing down. remove the cooler lines at the frame mounted filter, and flush the cooler? (15 psi air or a trans cooler flush aerosol). Hook it all back up, run around a bit, top it off.
Would that not replace all the fluid accept what is in the thermostat? (very little)
Frmr Ford Trans Engr
Joined: Aug 1999
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From: SE Florida
The problem with your method is that when the thermostat is closed there is only 10% of the normal cooler flow. The other 90% of the fluid goes to the pan instead of to the cooler.
So you can do it, but you'll only change a small amount of the total fluid and mix the old and new fluid in the pan.
Also, there is no reason to change the internal filter unless the trans failed. The frame mounted filter should be changed, but you're just wasting money changing the internal filter.
So you can do it, but you'll only change a small amount of the total fluid and mix the old and new fluid in the pan.
Also, there is no reason to change the internal filter unless the trans failed. The frame mounted filter should be changed, but you're just wasting money changing the internal filter.
Postmaster
Joined: Mar 2007
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From: Dunwoody, GA
There's also oil in the TC that's not released until it reaches a certain temperature, right?
Mark, how often is it recommended to change the frame mounted filter? I thought every 30k miles but can't remember off the top of my head.
Mark, how often is it recommended to change the frame mounted filter? I thought every 30k miles but can't remember off the top of my head.
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OK
I thought that the thermostat just controlled flow to the cooler. The cooler may only hold about a quart (guess).
Unless this is a different design,(very possible) the TC will flow at all times. That is where most of the heat comes from.
What I am suggesting is by-pass (or ignore it) the cooler for the flush, and then empty the cooler after the rest of the trans fluid is swapped out. As the thermostat opens, it fills the cooler with new fluid.
Not to high-jack the my own thread. But did anyone else realize that the torq shift is a 6 speed trans and that 4th is blocked out? (making it the 5 speed + tc lock)
I thought that the thermostat just controlled flow to the cooler. The cooler may only hold about a quart (guess).
Unless this is a different design,(very possible) the TC will flow at all times. That is where most of the heat comes from.
What I am suggesting is by-pass (or ignore it) the cooler for the flush, and then empty the cooler after the rest of the trans fluid is swapped out. As the thermostat opens, it fills the cooler with new fluid.
Not to high-jack the my own thread. But did anyone else realize that the torq shift is a 6 speed trans and that 4th is blocked out? (making it the 5 speed + tc lock)
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Mark
I just saw a procedure that helps me understand your post better. I should have stated that I was going to tap into the return line on the transmission side of the thermostat / filter, not the cooler side.
The by passing of the thermostat would not matter then.
I just saw a procedure that helps me understand your post better. I should have stated that I was going to tap into the return line on the transmission side of the thermostat / filter, not the cooler side.
The by passing of the thermostat would not matter then.
