Seeking Comments on a Novel ATF Drain Procedure

[TxGreaseMonkey]

Many people, in order to completely drain the pan and torque converter, disconnect the hose coming out of the cooler, start the engine, and pump the system dry into a container. Then, they drop and clean the pan, replace the filter and pan, and refill with ATF. Here's an alternative, for pans with a drain plug, that I just thought of:

Drain and clean the pan, change the filter, replace the pan and drain plug, start the engine and pump the remaining fluid into the pan, drain the pan a second time, replace drain plug, and refill with ATF. This might be a little less messy.

Give me your comments.

 

[Gary Allan]

There would be nothing to pump. The pump's feed is from the pan. That new fluid displaces the old fluid in the converter. Basically everything besides the converter and cooler lines (tank in rad included) is in the pan. Those are the only caches of fluid (of any appreciable amount). Basically, your pump would attempt to pump air..and spinning semi-dry.

 

[Black Thunder]

this is what i do.

i drop the pan/change filter and reinstall.

then i remove the line and pump out 2 quarts of fluid, then i add 2 quarts.

i keep doing this until i am satisfied with the color of the fluid.
put the line back on and run for several min.
check fluid level and add if necessary.

 

[Mike_dup1]

As stated, must be fluid in pan to pump out the old.

First, You need to drop pan and change fluid and filter. Re-install pan and add several qts of ATF (whatever the fill for pan is). Start engine and pump out the fluid into a container while adding new ATF untill you have added the required amount + any amount over that so you are confident you have all the new fluid you want. Most ATF shops will use 2 more qts to be sure. Adjust fluid to level, test drive and recheck level after operating temp is achived. Check for leaks and you are done. (NOTE-To remove fluid, loosen or remover cooler lines)

This is the procedure used by the ASE trans pros that have changed several of my trucks (to synthetic) over the years. Never any problems with this procedure.

 

[TxGreaseMonkey]

Thanks . . . makes sense. An Amsoil dealer I know uses the first method I described in his Dodge truck to pump the system "dry," before dropping the pan and changing the filter.

 

[Black Thunder]

thanks mike, i forgot to add that step of refilling the pan.

 

[GSDad]

Running a transmission dry, even for a short period, is risky, very risky.

 

[LACTD]

What GSDAD said. On the earlier 2nd Gen Dodge 98.5 up the drain back valve is removed because it is a restricion and potential failure. So at first start-up for day you shift to N and let it idle for 45 seconds, otherwise you have a dry converter and over time will kill it. :^)