the subject means should I plug the port on the tranny for the line that returns clean fluid to the tranny from the radiator?

Still working on my transmission. I want to isolate the transmission from the radiator to MAKE SURE there is no water getting into the tranny. can I plug the port on the transmission that comes from the radiator? (I have the line that goes from the transmission to the radiator in a bucket).

 

Just by pass it from tranny to transcooler to tranny.

 

If I understand you, you're saying to just bypass the radiator. If I do that then I can't expel bad fluid !? currenly I have the trans to radiator line in a bucket.

 

I haven't gotten all the answers and I think I worded things poorly. I'm going to try this again :-)

I need to flush my transmission on a 2002 F450. (I need to determine if antifreeze is getting into the tranny). I'm putting the transmission fluid line that normally returns transmission fluid to the radiator into a bucket. I have disconnected the other line that gets cooled transmission fluid from the radiator back to the transmission and I have put a plug in place of it in the port on the transmission.

If I did as another poster suggested and joined the return and supply lines together, I wouldn't be able to take out bad fluid.

So...is the plug fine or should I run that line into a bucket filled with clean tranny fluid?

 

If your goal is to take the Radiator out of the loop then you want the line with fluid coming from the tranny to go to one side of the transmission air/oil cooler and then a line coming from the same air/oil cooler dumping in the waste oil bucket. There will be no transmission lines hooked to the radiator. The transmission picks up clean fluid from the pan, pumps it through the internals and then out to the cooler for cooling then back. By having the return hose disconnected before it goes back into the tranny you will remove the contaminated fluid before it goes back in.

Is your coolant system fully serviced? If so watch the outlets from the radiator were the tranny lines would have hooked up. If the radiator is leaking internally you should see coolant coming out there. Might have to get warm before it starts leaking.

 

If your torque converter has a drain plug, than remove it and drain. Remove pan plug also. I would remove the pan and inspect. Install new filter, fill anthem flush if you want. I found it easier to add clean fluid to the full tube, I used those clear washer fluid bottles, just match how much fluid is going out with what you put in.

If you just flush, you are just draining a mixture of old and new fluid. Costly.
To check for cooler in tranny leak, plug one end and use shop air on the other end, and check for bubbles. Just turn the regulator down to 15 psi

 

Have you read this: Changing ATF Fluid in a E4OD and 4R100 transmission - Ford-Trucks.com

I think you are asking if instead of the plug, which you don't need, will it suck clean fluid out of a bucket? The answer is no, there is no suction at that port. You have to add new fluid through the dipstick tube.