How much transmission fluid is in the A/T cooler when it is cold?

[keystone]

I had transmission fluid changed a few months ago by a mechanic. But last 4 years I have a leaking transmission cooler (very very little that mechanic said it was probably okay not to change it now). Since it has been 10 years since my radiator was changed, I am changing the radiator myself and while I am doing that I thought I should change the transmission cooler. Before ordering ACM brand A/T cooler, which is about $230, I have a second thought since I don't want to lose much transmission fluid that hurts the transmission (not more than the amount that would leak in another 30K miles or until next transmission service). If the front of the car is on the ramp-about 10 inches higher, how much transmission fluid, do you think, I would lose while putting a new one (whatever amount is inside the old cooler plus any comes out from the hoses)? When the car is cold, does the transmission fluid drains to the pan so that there is not much fluid in the cooler? I have 95 525 auto.

[whiskychaser]

If you are lucky, your new rad will come with plastic caps covering the atf in/outlet. When I replaced mine, I disconnected the bottom hose first. I quickly screwed one of the caps onto the rad outlet and bunged up the hose. Lost about an egg cup full. Capped top, removed rad and drained atf into an old measuring jug. Filled the new rad with same amount of clean atf, capped it and installed it a la Haynes.

An old mate (a plumber) told me this method of connecting up live is called the 'snatch' method. My understanding of US slang is limited and dated but I believe this may not be something you say over tea with the vicar

[keystone]

If you are lucky, your new rad will come with plastic caps covering the atf in/outlet. When I replaced mine, I disconnected the bottom hose first. I quickly screwed one of the caps onto the rad outlet and bunged up the hose. Lost about an egg cup full. Capped top, removed rad and drained atf into an old measuring jug. Filled the new rad with same amount of clean atf, capped it and installed it a la Haynes.

An old mate (a plumber) told me this method of connecting up live is called the 'snatch' method. My understanding of US slang is limited and dated but I believe this may not be something you say over tea with the vicar

Thanks. Do you mean the two hoses next to each other when you said you disconnected bottom hose first? Transmission cooler and radiator are separate in my car, which is like this one: https://www.autohausaz.com/search/imageexpand.aspx?imageurl=../secure/PartImages/17201728770.jpg
There are two hoses next two each other that go into the cooler at the bottom and the cooler is in front of the radiator.

[whiskychaser]

Ah. Not only is my US idiom out of date but I assumed your atf cooler and rad were combined like mine:D If you can get at the connections easily I'd still go for the method I described. The system isnt under pressure and its a bit like emptying an upturned wine bottle. If your tranny has a dipstick, just measure what the cooler takes, pour that down the dipstick hole and forget I ever spoke

[Ross]

The cooler wil be full, it doesn't drain back.
Just refill the trans to the proper level. Who cares how much is in the cooler?

[keystone]

The cooler wil be full, it doesn't drain back.
Just refill the trans to the proper level. Who cares how much is in the cooler?

Thanks. I was hoping to hear that it drains back so that there is not much left in the cooler. Since the transmission filler is under the car and the car needs to be leveled, running at normal temp etc. (sounds complicated), I have no courage to do that, which is the reason I always take it to a mechanic for transmission fluid and filter change done recently few months ago. I am also not sure the type of fluid he put there so I don't want to mix it with another type of ATF.

[keystone]

Do you think it is possible to turn the cooler upside down by twisting and disconnect those two hoses since there will be enough room after the radiator is removed and the car is slightly elevated? In this way there wont be much fluid loss and I can add it into the cooler when I connect the hoses. Are those hose flexible enough? I am just trying to think how I can handle this and it sounds stupid even to me. But it might work if I don't break the hoses.

[genphreak]

Unless you have just done several fluid changes, try draining as much as you can- one only get's a third of it each time you drop the pan. Best to take the opportunity to replace worn fluid and replace to correct level by as per the precise BMW procedure. This way you knoe it's all gonna be good. If M50/M60, you really need a temp sensor and a long (large diameter) easy syphon tube, to avoid risking the wrong fluid levels.

[keystone]

Unless you have just done several fluid changes, try draining as much as you can- one only get's a third of it each time you drop the pan. Best to take the opportunity to replace worn fluid and replace to correct level by as per the precise BMW procedure. This way you knoe it's all gonna be good. If M50/M60, you really need a temp sensor and a long (large diameter) easy syphon tube, to avoid risking the wrong fluid levels.

Thanks. I have not done it myself so far, which is the reason I am a little scared since I am going to install new cooler and am afraid of losing some fluid during the process. I have had my mechanic change the transmission fluid every 30K.

[genphreak]

It is really easy on M20 and M30 cars as they have a dipstick. Later models without the dipstick are designed to be done on a hoist with the car level. The procedures are in the Bently manual and you can search for them here too. best ones to use are those that come from the BMW Techincal Info System (TIS).

I can't trust many mechanics myself, so if you don't trust him/her, do it this way. Make sure you use the absolutely right fluid, not something claimed to be compatible. Many use Dexron II, Dexron II and IV may not be as good. Mercon is the exact right stuff for most, I use Castrol myself, but beware names/grades- they differ between markets.

Sounds like you have had the fluid regularly changed though, so all should be fine either way.

[632 Regal]

The cooler wil be full, it doesn't drain back.
Just refill the trans to the proper level. Who cares how much is in the cooler?

It would matter a lot if it's packed full of goodies and beer :-)

[keystone]

Many thanks everyone for your help. I have installed a new cooler. I filled the cooler with new fluid and hoses are flexible so it did not seem like I lost much fluid other than whatever It leaked before I changed. But car seems to be fine and shifts okay.
Also thanks Bill R. for replying my radiator question in another post. The new radiator is working fine (Behr-Made in S. Africa).
In the last 6-8 months, I did a lot of installation myself (radiator, transmission cooler, water pump, thermostat, aluminum thermostat housing, upper and lower coolant hoses, mechanical tensioner, all the pulleys except for PS pulley, fan clutch, belts, knock sensors-it was giving knock sensor errors, spark plugs, fuel filter, and oil change). Only thing that has been ignored in the car for the last 6 years is bleeding brakes ( maybe I should do that myself too). Finally car seems to be running well unless something goes bad soon (hopefully it does not happen when I am on the road).
Again many thanks for your help and it is a great feeling to fix things that work.

[Russell]

The cooler wil be full, it doesn't drain back.
Just refill the trans to the proper level. Who cares how much is in the cooler?

My indy blows all the fluid out of the trany cooler ( to increase the amount of new fluid) when they service my trany. That's why i care. :)

[genphreak]

Good o. Keep it up. Sounds like u better bleed those brakes now, old fluid is not good for the rubber, cylinder surfaces or performance.