I recently purchased a stronger 4L60E tranny from Flyer, and I'm busy in my garage popping it in.

I got the old one out no problem (besides those stubborn glued connectors on the circuit board).

The new one is in, no problem. Bench-pressed, no tranny jack used :cool:

I am just wondering if anyone has any suggestions regarding flushing the tranny lines and the factory trans cooler. I really don't want to hook up the tranny with all that dirty fluid in the lines!!!

thanks,

Chris

There's always a degree of dirty trans fluid in there, shouldn't be a problem.

I used to have a trans line/cooler flush kit. If you just blow it out with compressed air you will be ok. Just keep your eyes safe. Is there any debris in the old trans?

That canned stuff that I was telling you about will work good. The only thing is you might have a hard time finding it. It's sold as 'trans cooler line flush' or something similar to that. It has a threaded end on it and will fit on the bevels of the stock lines if you push and hold it hard enough. If you have an aftermarket trans cooler, cut the threaded fitting off the hose on the can and just stick the hose in the line for the cooler. It will fit JUST right inside the line. Be sure to clean out both sides if you do that.

The trans is a lot more sensitive to dirt and foriegn material than an engine. The burnt fluid has ash from the old friction material. That ash acts as a lubricant,kinda like tiny marbles on the new clutch surfaces. I'd clean it as best you can.

Flyer makes a good point. If there is ANY debris in there you need to get it out!!!

I agree on the debris. Didn't know the fluid was fried.

Just hook it up the best you can and run it to the nearest shop and get it flushed. Just make sure they use the internal pump and not an external. Good piece of mind for $100 or less.

Well, we should know the total fluid volume of the transmission system.

What about filling up a clean 5 gallon bucket with the total fluid volume of the system, and running a line from the suction side of the system to that bucket. Then getting another 5 gallon bucket and letting all the old fluid in there. Just have the truck runing, idling in park and shut it off once the all of the new fluid id in the tranny.

Would that work?

Fandango .. good diea, but it doesn't work like that. There isn't a suction side, only a pressure sid. The pump pushes the fluid through the coolers and back into the trans where it's exhausted into the pan eventually.

brake cleaner or alcohol - like brian said - use compressed air on a lower psi setting.
and flush the lines and the cooler - flush until it the fluid/cleaner coming out is clear

Naah .. use 90psi at least. More air, the better it cleans. Trans fluid sees 100 psi at low throttle positions, 200psi at WOT on a stock trans.

That's why you use trans cooler line, and not high pressure fuel line or something else cheap. ;)

I ended up renting a small air compressor and blowing air through the lines at 200psi. Worked very well!!

I also bought a new tranny cooler, roughly twice the size of the stock unit.

Chris