Every time I had some shop flush my trannys in the past the tans always failed at the most a year latero No: So no tranny flush for me...
What's with the bucket of new fluid? There's no pump to deliver it to the transmission. I disconnect ONLY the return tube at the trans cooler, and let it hang in mid-air. I use a length of parts-store tubing on the cooler outlet to direct the fluid into a drain pan. That way, the trans cooler gets flushed, too.
so you disconnect the line that goes back to the tranny at the cooler and you let that drain into a bucket. and then you must add fresh fluid into the filler tube so it doesnt run dry right? and you do this until clean fluid comes out the return line? and are you saying that Devons way will not supply fluid back to the tranny? so the tranny is pushing fluid and not pulling.. for devons way to work the tranny would have to be drawing it from the cooler. and you are saying that it is pushing it TO the cooler which forces it back through the return line. Interesting.. Devon what say you?
According to TCI, the TH350 and TH400 use the fitting at the top of the transmission for fluid return (into the trans), the bottom trans fitting being fluid output. Don't rely on the radiator connections to distinguish inlet/outlet. Devon
You certainly do have a pump. Run the engine at idle and the converter will do its usual thing. It's not like it's line pressure or anything. Devon
ok but devon, does the tranny draw the fluid from the cooler or does it push the fluid to the cooler. or both, because if it only pushes it, then Shurkey is right, what will make the fluid go back to the tranny?
This is done after the filter change. Again, the old fluid will be pushed out the bottom fitting, new fluid will be pulled in through the top fitting while the engine is running. When the fluid coming out appears bright red and clean, shut it off and put it back together. Do a final check on fluid level and drive. The rotation of the torque converter is what moves the fluid. Devon
When you say intake line is also return line right? would it be ok to only disconnect the intake line put it in the bucket of new fluid but then let the fluid come out of the cooler instead of the line going to the cooler. This way the cooler gets flushed? Will that work? I liked Shurkeys idea about flushing the cooler.
NO the intake line is not the same as the return line! Print this thread and go look at the two tubes attached to your transmission. Yes, you can certainly leave the output line connected to the cooler and run a hose from the cooler's outlet into the empty bucket if you want to. If it's still not clear just have a shop do it for you. Devon
I've been doing this procedure for years, and what you're saying is not clear to ME. :^) There are two tubes attached to the trans, that go to the cooler. One is pressure, or OUT from the trans. One is the return, or back IN to the trans. The trans OUT tube goes to the cooler IN port. The cooler OUT port goes to the trans IN tube. There is no mechanism that draws fluid out of a bucket back into the transmission. Not even vacuum, provided the trans vent isn't blocked. In normal operation, the trans pump pushes fluid OUT, through the cooler, and the returning fluid lubricates the gear train of the transmission before returning to the pan. Putting the return tube into a bucket during trans flush does nothing useful that I can figure, because I don't understand how the bucket fluid could return to the trans since there's no pump to move it; and the geartrain doesn't need lube anyway because the wheels aren't turning while you're servicing the trans. The pump moves the fluid from the pan to the converter to the cooler OUT/pressure tube, through the cooler where it's drained into a drain pan. The IN/Return tube does NOTHING except maybe drip a little; which is why I just let it hang, connected to nothing at the cooler end until the flush is done. Of course, the flush is best performed AFTER you've dropped and cleaned the pan; and replaced the trans filter, and reinstalled and re-filled the pan with clean fluid. That way, the only dirty fluid left is in the passages of the transmission, and the converter.
I remember having no problem with being able to draw fluid from a standing container, maybe I don't remember having done it as you described, as I see your point. Maybe I drank too much antifreeze back in the day. Devon
It's official, I'm losing it. My Ron Sessions book describes the procedure as Shurkey did. I'll shut up now. Devon
Now this proceedure seems more likely to do the trans then what I have had done to my cars in the past. I used to have techs hook up the cooler lines to a machine and flush the trans out that way. Still 3 trans later the proceedure still left my trans with failure and the tech with a pocket full of money:error:
Actually, you have me thinking that I should try it your way--but deliberately block the trans vent. IF (big IF) there are no air leaks into the trans, the trans would self-fill once it developed some vacuum inside. I don't know how well this would work; and trans vents aren't always easy to get to. I'll have to look into that some more.
Thats a good idea, hopefully things are clear to you now. LOL. Maybe YOU should have a shop do your work for you from now on. BWAHAH HAHA, it seems you have some things to learn before instructing and criticizing others. *chuckles* and yes according to Shurekey explanation the transmission intake line is the same as the cooler return line. Good day sir. haha
On a day like this, you're absolutely right! I have no doubt I would butcher an oil change right now if you gave me the chance. I deserve the :spank: Devon
There is a reason for that :Smarty: If the fluid in your transmission is dark and burt smelling, changing the fluid is usually the kiss of death. If the fluid has never been changed in a 100k miles and the fluid is in bad shape, leave it alone! I guarantee you you'll be putting in a rebuilt trans in short order.
That's the thing it was never black or even brown as old trans fuids get....At the most just a little more transparent/ faded red color.
