Flushing 722.x trans via rad pipes

[spock505]

Hi folks,

Having carried out 2 full changes and one part (no TC drain) I wondered if it were possible to drain without damage via coolant pipes?

I need to change mine anyway, so thought about doing another flush at the same time putting the feed into suitable container whilst engine ticking over. Fill capacity known, so filling a graduated container and stopping before reached could help running dry.

It doesn't seem to be a popular method so assume there is a major potentially destructive draw back?

Thanks,

[spock505]

..just to clarify, it would be to drain only as opposed to filling from another container - rust even on the fittings is a big concern, pulling that into the new fluid would be big risk.

..btw, anyone have part numbers, EPC is not listing my layout - ta..

[sixto]

There's insufficient suction through the cooler lines so that's not the way to fill. The process when there's no TC drain is to have someone mind the key while you pour a gallon of fresh fluid through the dipstick or fill port as old fluid is purged. You need a second person because you can't fill as quickly as it purges so stop the engine as a gallon is purged so you can catch up with filling. There's no harm running a couple of quarts low while not moving. The second person can run through the gears to clean fluid in the valve body. Make sure you trust this person and stand by a fender rather ahead of the car. Repeat until the effluent looks like fresh fluid. For most cars that's a couple of gallons.

I've done a number of fluid changes this way but never on cars that didn't have a transmission dipstick. I don't know how that complicates things.

Sixto
83 300SD

[optimusprime]

I think a pipe change would be needed first .Thats looking at the picture in the post above.Rust will fail , and to will the gearbox..

[oldsinner111]

Yes change lines,I'd be worried about the radaitor,some rot inside letting trans fluid mix with coolant.

[shertex]

Curious that you have no torque converter drain… I thought that was eliminated in 1999.

[spock505]

Thanks for the replies, yep there is a TC drain which I used on the first two full changes but not on the third part change (my poor wording).

If I can get the correct part numbers may well miss out changing just the metal tube, undo at hose ends avoiding any possibility of rust contamination.

It's always had the plastic under tray attached to my knowledge, not sure why its in such bad shape. Worm drive clips will all be changed to, have some nice marine grade stainless to go on.

[spock505]

Its possible the pipe has swung down under the bracket and now rests on soggy foam undertray, anyone have a pic of theirs for comparison? - ta

EPC brings up the following part numbers for my VIN, thing is my metal pipe doesn't join at 90 degrees?



This looks better although listed for the 436, mines a 435