Getting my rebuilt trans back this week and I want to flush the lines and tranny cooler of all the old fluid/junk.

What is the best way to do this (without a flush machine)?

Thank you!

-Brian

 

I just put some garden hose over both lines then pumped a gallon of Walmart Dexron III through the lines and coolers with a hand pump. Then I blew out the fluid with air, I believe the rear line is the return.

 

When you are done, install a filter adapter and filter on the return line. It will make the new transmission last a whole lot longer, and catches the small particles that will only wash out of the oil cooler when it starts bouncing down the road.

 

I ran a can of this http://www.lubegard.com/automotive/t...ler_kleen.html through first and then then a can of brake cleaner followed by plenty of air and then some dextron. Lots of junk came out after the brake cleaner. I flushed it both directions, reverse first, and glad I did it.

 

On reverse flushing, must remove one way check valve in many cooler lines. You are corect in rear line is return. I have used paint thinner and air pressure. Clean each section of line and coolers. Be aware that some coolers have a theromstat bypass built in. there is a repair kit to rebuild. See module where connects at front cooler. Adding filter just adds to restriction of circuit, which is something you don't need. Get it clean. A siphon type air gun is great way to clean.

 

Thanks guys for all of the information. I have read your posts, but I am not sure which lines to hook up to for the flush, and how would I get a garden hose to seal on the trans lines? If anyone could write a step-by-step process, that would be great. Also, where do I find these hand pumps you talk about?

Thank you all for your help and time. It is hard because I don't have the truck in front of me, so I can't look at it in person and figure out what lines. Some of you mention front are rear lines? Don't the lines just go from the left and right side of the trans/motor to the cooler?

Again, thanks for the help!

 

I would suggest removing the one-way check ball/valve.
But spray some brake cleaner in, followed up with air and blow it through the lines, and cooler out the other line into a pan

 

Walmart has oil pumps in the automotive section, its just a cheap plastic tube with a piston and handle.

On the drivers side of the transmission there are two lines. The one towards the front of the truck runs to the heat exchanger (passenger side of the block near the firewall). The other line on the heat exchanger goes to the air cooler (raise the hood, it looks like a small radiator on the drivers side behind the grill). The other line on the air cooler runs to the rear line connection on the transmission (thats the return line to the transmission).

Just disconnect the lines at the transmission, and slip two pieces of garden hose over the lines. The hose I used fit tight, but you could use screw clamps or zip ties as well. Pump what ever you want to flush with into the line thats toward the front of the truck and drop the other hose into a bucket.

If you want to flush both ways, there is a check valve that I believe is located between the hard and soft line on the heat exchanger.