Trans fluid on my car has never been changed in the years I have had it. I think its about time I changed it out.

I read through old posts and it seems like forum wisdom is to do an "exchange" out of the upper radiator fitting. Few questions I had:

1. What size hose goes on there without a clamp? 3/8?
2. It looks like fluid capacity is 8 quarts? If so, can I change out all 8 or do I change out 4 for now, drive a 1000 miles and change out another 4 quarts?
3. I will be pumping out 2 quarts at a time and adding back 2 in instead of running it dry - any thoughts on this?
4. Castrol Transmax for Imports - this is what I plan to use. Any reservation or recommendations?

 

transmax import is what I used...

I got one of those fancy transmission funnels with a on/off valve at the bottom and a clear vinyl hose with a fitting for the dipstick tube. I cut the hose way shorter than it came, and rigged up a coat hanger to hang said funnel off bottom of hood.



my method was to first warm up the transmission thoroughly (I drove about 15 miles on county roads), then use a oil sucker to get as much out of the dipstick as I could, this got about 2-3 quarts. disconnect that top hose, run it into a graduated container, and now through the dipstick tube add as much ATF as you removed with the oil sucker.

start the engine and let it idle, each quart that comes out into your container, add a quart, I did this as a continuous process, repeat this until the stuff coming out is clear red. shut off engine, replace cooler hose.

test drive a few miles, with engine idling, check trans dipstick, and top off if needed.


note, btw, these transmissions don't have a conventional filter inside, they do have a screen, and its not a bad idea to drop the pan and check/clean this screen, it rarely needs replacement unless you abuse it.... before dropping the pan, clean the heck out of everything around it, as even a speck of grit can destroy a transmission.

 

Thanks Pierce! Turns out the nut on the transmission line is frozen solid. I soaked some rust penetrant on it and plan to add some every day for the next 3-4 days.

Don't want to break the mated fitting inside the radiator....

 

you need a pair of flare wrenches for those. one for the hex on the fixed part of the insert, the other for the actual flare nut.

 

Gotcha....do you know what size the fixed part inside the radiator is?
I was looking at a set with 15m, 19mm and 22mm....the 19mm wrench that I have does not fit. 22mm?

 

i dunno,, measure it with a caliber ?

 

I tried opening that fitting with a pair of flare nut wrenches that I borrowed from a friend. It does not budge, I can move the entire engine with it.

I am thinking that the fitting is rusted on to the pipe. So I am probably going to have a shop just drop the pan, change the filter and replace the fluid that way.

 

So I finally got around to breaking that flare nut loose.
Can someone advise what size hose is needed to connect while draining the ATF out of the cooler line?

 

 

As an FYI I usually take the line off at the transmission. Works out for me as I have a lift and it's not an issue to get under the car.

 

Sounds good - will keep that in mind the next time I end up doing another flush. The new fluid seems to have cured some of the harsh shifting I would observe after freeway driving.

 

Would a best practices be to drop the pan and clean the screen first, then proceed with the flush?
Any advantages in using a synthetic atf? Any recommendations on an accessory cooler and it;s location?

 

I never had any issues with my ATF overheating even towing while heavily loaded in my 740T wagon, climbing the sierras aggressively in 100F weather, but the turbos do have a bigger stock cooler and my 740 was a 92 which had a larger radiator.

I think the best ATF for these is a quality classic Dexron III, like Castrol's Transmax Import Multivehicle... note the AW7x automatic transmissions are from Aisin, which is Toyota's transmission division, these are essentially the same transmissions used in cars like 1980s Turbo Supras, and many generations of RWD Toyota pickups. I've heard a 'synth' ATF can cause transmission seal leakage

I've always drained it, then drop the pan and clean the screen, reassemble, add sufficient ATF to bring it up to the cold line, and disconnect the cooler return hose and idle the engine in neutral while pouring in more via a dipstick funnel until it runs clear from the hose... i keep track of how much comes out and how much I added to flush, and use that to figure out about how much I should add, then drive a half hour and check it against the 'hot' mark