[RolHammer]

In threads like this one

http://www.odyclub.com/forums/showthread.php?s=&threadid=65442

really great information is given as to performing an ATF flush. One aspect of the process remains problematic, however: put the fresh ATF back in. If you've got a 2nd Gen with the jet kit installed you can't use the ATF fill plug and have to use the dipstick tube. However, pouring the fluid in through the dipstick tube is pretty slow.

Because the return line's not under any suction, there's no way to 'pull' it in. But, after I did my own flush accoring to cnn's excellent instructions at the thread linked to above, I was mulling things around in my mind & got to thinking 'Could you maybe push it in instead?'

Basically, the concept I'm thinking about here is using a manual transfer pump during the time when the ATF return line's been removed during the flush phase of the operation. Essentially, the idea is taking a pump like this one

or maybe this one

and putting the pump's 'out' tube into the return line back to the ATF sump and the pump's 'in' tube into a containter of fresh ATF. Then, just suck in and push out until you've got the necessary volume put back into the sump. (In the technique in the thread linked to above, you'd be putting 4L back in after the initial drain and ~2 L after each step in the flush process).

What does everyone think - would this simplify the process any ?

 

[0dyfamily]

You definitely have the angle on these neat shop tools, RolHammer.

You still have to drive it between drains/refills to move fluid out of the torque converter, but you may be on to something here.

OF

 

[Laphroaig]

Last time I changed the ATF, I let it sit on one of my hot water radiator (it was winter) to let it warm. Viscosity was lower and it was much easier to pour it in the dipstick hole.

I'll try to unscrew the ATF plug next time...

 

[RolHammer]

Last time I changed the ATF, I let it sit on one of my hot water radiator (it was winter) to let it warm. Viscosity was lower and it was much easier to pour it in the dipstick hole.

I did mine on a warm spring day. I just put the ATF in the vehicle, which I'd parked on the driveway in the sun. It was very warm in there and the stuff poured pretty well.

Visocity wasn't the holdup though. The 3/8" tube (or whatever the diameter is) you've got slipped down into the dipstick tube is the rate-limiting factor IME.

You definitely have the angle on these neat shop tools, RolHammer.

You still have to drive it between drains/refills to move fluid out of the torque converter, but you may be on to something here.

Thank, OF. Yes, you're right - you still need to actually drive it, moving through all of the gears, including reverse to ensure fresh ATF's displacing old in all the parts of the ATF. Also, the whole ATF replacement process in its proper form is much larger than just a single iteration of 'flush & fill'. I was just thinking this pump thing might take some of the pain out of the process.

And, speaking about the serial 'do this whole thing three times' aspect of the process as it seems to have evolved into - how necessary is that, really? Seems like a single iteration of cnn's process in the link above replaces 91-92% of the ATF (twelve liter capacity, I found it took eleven liters before pristine ATF started coming out of the return line on the cooler). The pragmatist in me urges me to call this 'close enough' and halt at one iteration versus chasing after that remaining small percentage, pushing against the headwind of the Law of Diminishing Returns at ~$80 an iteration (11 liters at $7.74 a liter). My thought is just one iteration of the fill & flush, keep that $160 in your pocket (and that additional 22 liters out of the recycling stream) and call it a day. Perhaps a slightly more frequent interval could be employed, but only enough to try to realign the mathematics of the 92% completion of a single iteration vs. what you'd get with three iterations each time.

I dunno, maybe I'm looking at this the wrong way or not considering all the facts but that's what I see, looking on this as a total layman. <shrug>

 

[0dyfamily]

RH, I believe the reason for all this multiple drain / refill business is to get to higher speed, liberate fluid entrained in the torque converter so it can mix with the rest of the fluid, then drain again...and again...and again....and winning the dilution battle by doing it a total of 4 times.

I remember when you could drain a car's T/C. Then again, I remember when transmissions came in 3 flavors (GM TH400, 727 TorqueFlite, and Ford C series)we never changed tranny fluid.

OF