pneumatic ATF flush

[towncar]

Hello everybody.

I have a '94 Rover 827 coupe with Honda C27A1 engine and automatic transmission, 211k km mileage. According to the service record i received with the car, it had a transmission oil changed at 160km, which is 50k km time ago. So time to change, especially that shifting is harsh and noticeable , eg. when when switching from 1 to 2nd gear.

I'd like to flush it completely with Valvoline Maxlife ATF as it is advertised as ATF-Z1 compatible. Unfortunately Genuine Honda fluid is >$33 at my area, while Maxlife is $14.

Here is my plan of flushing it, check this diagram i drew:

will it work? the air from the 'old fluid' container would push out the fresh fluid into the transmission. can anyone used this method?
or i should rather collect the old fluid into some container and pour the fresh one through some funnel? any advice unappreciated. thanks.

 

[towncar]

>any advice unappreciated.

of course i meant appreciated! my firefox spellcheck corrected it wrong.

 

[INDYMAC]

It looks like similar technology to the BG tranfer systems here in the States. I did this recently, but I think the next time I do it I will do the tranfer of fluid first. Then I will drop the pan and check the plugs, clean the pan and filter. Once that is finished, I will top off the fluid with the new stuff (2-3 more quarts). I think this procedure would cover all aspects of a complete fluid flush.

 

[towncar]

The drawing i posted its just my idea, i don't know whether such technology is used. The fluid containers would have to be completely sealed to make it work. So i was wondering whether such method is used. My understanding is that the same amount of fluid exits and enters the transmission, if not one of the container could explode.
Of course i could perform standard flush, with a funnel, but it could be messy and more difficult pour the fluid.

My transmission has only one drain plug and i cannot remove the pan, and can't drain the torque converter, so i have to flush it to replace the fluid.

 

[calvin1]

Are you sure you need to make a completely closed system? I know that on my transmission that I can refill it with the cooler supply depositing old fluid in one bucket and the return picking up the new fluid from another. I have a helper run the truck until the new fluid is all gone and then shut it down.

Calvin

 

[bcossa2001]

Calvin--do you have to disconnect 2 lines? Would it work if you cut only 1 line (regardless where it goes/comes from)--submerge the end that supplies fluid to the trans in new fluid and run the other end (the end that takes fluid out of the trans)to a waste receptacle? As long as you have new fluid going into the trans does it matter where you cut the hose??

 

[unDummy]

towncar, that will work well if it is completely sealed. This is basically how all the ATF flush machines work. If you have an ATF drainplug, start with a drain/refill of the pan first. This will increase the amount of old fluid removed. Since air is compressible, you'll have an expansion tank situation. The amount of clean ATF returning will be less and slower then what is being pushed into the old bucket. Use clear plastic containers so that you can watch the old and new ATF levels. Even after you shut the vehicle off, pressure will continue to push new ATF into the transmission allowing it to catch up, until PSI drops to nothing.

Sorry Calvin, but ATF pump pickups are in the pan. It can not siphon fluid from the cooler hose. The cooler loop is pressure only. There is no vacuum. This happens to be one of the biggest internet bogus hearsay out there.

 

[bcossa2001]

Thanks, undummy. I just learned something...

 

[Donald]

Why not just drop both lines from the cooler into a waste oil bucket and pour in fresh fluid into dipstick until you see fresh fluid coming out. You will need 2 people as you really want one person to concentrate on pouring in new fluid.

 

[Donald]

I also think even a little air pressure would blow up the buckets of new & old fluid in your diagram unless you really had sturdy ones.