I am planning to replace my trans cooler lines. Any ideas on how much trans fluid I need to drain out?

Does anyone see any objections to just pouring the ATF in my fuel tank?

Thanks,

Dkr.

Why not just plan a fluid/filter change while you're in there? What is the rationale behind replacing the lines? Are they worn?

Don't pour the ATF in your tank. If you have any metallic pieces or friction disc shards, they'll be consumed by your injection system. Additionally, ATF smells HORRIBLE when burned!

__________________
Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]

I have no idea what vehicle you are dealing with, but most vehicles won't lose more than a few ounces of ATF when the cooler lines are disconnected.

In where? The garage?

__________________
When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

Sorry, it is a 1984 300D. The trans fluid and filter were recently replaced about 5K miles ago. The lines are just worn and look like they are about to fall apart.

Dkr.

Hard lines or hoses?

__________________
When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

The hoses...

Dkr.

I would not do anything but place a drain pan under the hoses when they are disconnected. Draining the transmission itself won't accomplish anything.

__________________
When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

You won't lose much. Maybe have some small plugs ready to limit loss. Just top off after hoses are replaced. Be careful removing the hoses from the rad nozzles. If they are tight use some PBlaster or similar and maybe a pencil torch on the nut.

While in there, it might be a good idea to have a look at the nuts that hold the transmission cooler nozzles in place (and provide a seal). I had one of those nuts split in half, all of it's own accord. Just noticed the coolant leaking. Discussed in link below

85 300D Radiator bottom nozzle leak

__________________
Graham
85 300D,72 350SL, 98 E320, Outback 2.5

If you run the front up on ramps, you probably won't lose but a few ounces of ATF, but do have a small pan ready. As I recall, you need to hold a backup wrench on the radiator side so you don't shear off the cooler fitting and perhaps ruin the radiator.

I guess you could burn leftover ATF in your engine. Other than oil, it is mainly just "friction modifiers", which originally (Type A) were things like whale oil. Of course, filter it first to at least remove fine metal shards, indeed run it past a strong magnet too. I discard used ATF by lubricating my electric chain-saws, by just pouring it on the chain. But, my sanitation recycles it as "used oil" if left at the street.

__________________
1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

Thanks for all of the responses. I did the job today and it was very easy. I had about an ounce of used ATF that I filtered and dumped in my tank.

Dkr.