Flushed my transmission today

[JackFish]

Ford C4, type F.
I stuck a plastic hose on the cooler line and ran it into a bucket with liter markings.
Started the car, and it pumped about 2 liters out before air came up. Refilled the 2 liters. Repeat process. Run it through the gears. I used 8 liters.
I initially ran a hose into a fitting on the cooler to top off but discovered that gravity feed won't work very well. It would seem the fluid must be "pushed" through the cooler.

 

[BuickGN]

You should be adding fluid as it's being pumped out. Not the best idea to let it run dry. The pump doesn't like that very much.

 

[JackFish]

Next time I will definitely do that, just to be on the safe side.
Went for a drive and everything seems OK, shifting very smoothly, (knock on wood)!

 

[unDummy]

I've said it before. ATF pickup is in the pan.
Splicing into the cooler line loop is like cutting your garden hose in half. Don't expect the handle to siphon. You need to top off the sump/well through the dipstick to do a cooler line flush.

As long as you don't purposely run the pump dry for an extended period of time, no harm is done.
You can 'overfill the dry unit' and move a gallon or more through it quickly without having to start/stop/start.... in 1-2 quart intervals.

C4 and type-F? Must be older then many members here. What vehicle?

 

[JackFish]

Thanks for the tips.
It's a 1978 Ford Fairmont with a straight six 200!
I did it in intervals to keep a close eye on how much ATF I putting through it.
But now that I've done it once I now know what to expect.
Piece o' cake!

 

[Donald]

unDummy - so do you suggest filling via dipstick while its running out into drain bucket from cooler line (probably need 2 people) or run it until you see some air bubbles, shut it down then add what was pumped out and start up again?

 

[unDummy]

I always run until sign of bubbles. You will not keep up with the output of the ATF pump. The dipstick diameter is too small.

And after initial shutdown, I add what was pumped out, plus several extra quarts, restart/run until bubbles come out again, top it off with original pumped out amount, check level, & refill the beer mug.

 

[Donald]

So running with too much is only a problem if you are actually driving the car?

 

[Kestas]

I've done some transmissions where, if you have a tight fit between the funnel spout and dipstick tube, the transmission will suck the fluid in and you can essentially keep up with the outflow as long as you can pour it from a big mouth container.

 

[Donald]

Does anyone worry about the fluid that is actually in the cooler? Doesn't it get missed? Or too little to matter?

 

[unDummy]

Why worry? For the cooler, disconnect the line 'exiting' the cooler and not feeding it. But, as always, any maintenance is better then none so pick the 'easier to access' line, which does not have to be the optimum choice. Some will simply blow the ATF cooler empty with compressed air.

Running too much ATF or running out of fluid is only a problem when driving the car.

Yep Kestas, since pumping out the fluid creates vacuum, it is possible to have fluid drawn in if the tranny is relatively sealed. Many are vented(case vent, seal leakage, open dipstick, and of course the open cooler line). And, the vacuum may NOT be friendly to some seals. I don't care to purposely create 'that vacuum' by blocking off those vents.

 

[Greggy_D]

Quote:

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top it off with original pumped out amount, check level, & refill the beer mug.

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Best part of the job!

 

[BuickGN]

Quote:

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I always run until sign of bubbles. You will not keep up with the output of the ATF pump. The dipstick diameter is too small.

And after initial shutdown, I add what was pumped out, plus several extra quarts, restart/run until bubbles come out again, top it off with original pumped out amount, check level, & refill the beer mug.

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While I realize the C4 and it's gearator (sp) style pump may not be as sensitive to fluid loss, the vane style pumps really don't like to be run dry whether driving or idling in neutral.