5R55W flush procedure?

[Russ in CT]

I just got an '02 Ex, SOHC V6 with 5R55W (no dipstick). Its got 107K on it, so its technically not due for a tranny fluid change for another ~40K miles, but I think even 100K is too long. So I want to change the fluid. But if I just drop the pan, replace the filter, then refill, I'm leaving a lot of old fluid behind. Is there a way to completely flush it?

What if I drop the pan and change the filter (clean pan, clean magnet, etc), prefill approximate level, then use the tranny cooler lines to flush it? Hook up intake line to fresh fluid, output line to bucket, and run engine until clean fluid comes out. Then let it drain from the 'fill plug' at the bottom of the pan until its at the proper level (or add if its low).

Will this work? What is wrong with this plan?

 

[CDW6212R]

Many people do that, and I was planning to also with my 99 trans. I think that they run the engine to push out a gallon or so to begin with, and then drop the pan etc.

I would suggest adding a trans filter up front though, that is good insurance for most Fords.

 

[BrooklynBay]

You should use Mercon V fluid even though a lot will be wasted. This is the correct fluid for this transmission. A lot of people like Amsoil or Mobile 1 if you choose full synthetic fluid. Lubegard makes friction modifier additives which are OEM approved.

 

[CDW6212R]

Yes use the best fluid, and be very careful if you buy the Lubegard. They have a different version for Mercon versus the Mercon V. The front labels of the bottles are not all clear, read the backside carefully. Regards,

 

[Russ in CT]

So reading the posts on 'flushing' the tranny fluid, I see that the cooler lines don't suck any fluid in, just push old out. So you can't just use two buckets (one with clean fluid) and do a fluid flush.

What was mentioned in those threads was to keep starting and stopping motor, to pour a new quart in the dipstick tube, to match the old stuff coming out. Well we can't do that with our 5R55W, since it doesn't have a dipstick.

What if I use the cooler line like a dipstick tube? Take the 'intake' cooler line, run a longer hose to it, extend up higher than the tranny and put a funnel in it? Use the 5R55E method of pouring in new quart for each old one, only I'm pouring it into the oil cooler line, using gravity feed to force it in.

Thoughts? I'm trying to find a way to change the fluid without leaving a bunch of old fluid behind (which just dropping the pan would result in).