Trying to get to hard-to-reach bolt on the ATF return line

edelmatt · Post by **edelmatt** » 13 Mar 2011, 10:52

Hi All.

I dropped the pan and changed the filter/gaskets on my 240. I have the car back together and running now, but the procedure only replaced 3.3 liters (or so) of the fluid. Apparently there is a total of 7 liters in the transmission. Or close to that. I don't have the manual in front of me at the moment. I want to flush out the old fluid completely (or as completely as possible with the transmission installed). The manual suggests the method of draining the fluid 2 liters at a time through the fluid return line above the pan.

It says to disconnect the cooler return line, attach a clear tube to it, put the tube into a drain pan, and run the engine until bubbles show up in the fluid. Then stop the engine, add 2 liters of fluid, and repeat the process a couple times. Presumably this will circulate and empty most of the fluid volume in the transmission.

But it is very difficult to get to the bolt which holds the return line to the filter housing. I can just get to it with a wrench if I have the pan off. But the pan needs to be in place for the procedure. I can also get to it if I remove the exhaust. But I can't imagine I should be running the engine with the exhaust removed.

Do I need a special wrench for reaching this bolt while all the other components are in place? If I need to uninstall/reinstall the exhaust just to do this then I'll bring it to my mechanic.

Thanks all. I really enjoy reading the threads and hope to add my expertise to the discussions when I have any

Matt

Post by **JDS60R** » 13 Mar 2011, 11:34

Disconnect it at the radiator.
Fill the trans up as much as you can and then turn it on, You can watch it pump the fluid out the line. Add more as needed.
In many transmissions I can add more than is left after the pan drain. If there is 4 qts left I will put in 5. When the line is flowing clean , new fluid I turn it off. You don't "have" to run it dry. It actually likes it better when you don't .

Reconnect the line and fill to proper levels. Check the fluid level and inspect for leaks each day for about a week.

Use 2 wrenches on the rad. You must support the rad fitting with a wrench or you risk tearing it out and buying a new rad.

lummert · Post by **lummert** » 13 Mar 2011, 14:50

It is much easier to undo the line at the radiator. The top line should be the one you want.

edelmatt · Post by **edelmatt** » 13 Mar 2011, 21:31

Thanks guys! That's such a simple but clever answer. It's like my mechanic says, "you don't pay us for what we do you pay us for what we know." I'll have a chance to do that probably in another couple weeks.

Question that will be answerable once I get the car raised again: from the top connection on the radiator, is the fluid flowing in or out of the radiator?

Thanks,
Matt

edelmatt · Post by **edelmatt** » 14 Mar 2011, 11:42

Final question: Do I need to shut down the car in order to refill the fluid? Or can I leave the funnel in place and add fluid as the engine is running?

lummert · Post by **lummert** » 14 Mar 2011, 16:12

It may pump out fluid faster than you can add it.