I'm going to be doing my first DIY Tranny Flush. I've read the procedures in the tech section several times, but I'm still left with a question.

How do you know when you've pumped through enough fluid? In the example they pump through 8.75 litres. How did they know when to stop?

Thanks.

 

If they stopped at 8.75 liters they changed just over half of the total.

Does the procedure mention the trans needs to be over 170F and the new fluid needs to be hot, too? If not the thermostat will not be open and most of the fluid from the pump returns to the sump without going to the cooler.

 

Do you any better methods? maybe a little more detail. I know how prep for the flush and how to clean up. Id just like a little more detail on the actual flush process.

 

The way I do it is:
I give the transmission shop $149.00 and have a cup of coffee while they do the work. To me, the cost is justified. It'll cost about $100.00 to do it yourself; 22qts + 2 filters + the goodies you need to do it... Again, I'll pay the price and take the free coffee! OH! And then you have to find a place to recycle the old fluid. It's not impossible, but it can be a logistical pain.

 

They are keeping track of what is coming out so they know where to stop and how much to add. the tranny holds 18Q your not gonna get 100% of it..drain the pan 8-9Q then add that amount back into it...then start the truck and let the pump take out the other 8-9Q then add that back in.

 

The Tech article by Bearhunter in the tech folder is very specific that you measure everything you take out so then you know when you have changed all of it.

 

Yes you have to measure how much you pump out so you know how much of a flush you actually did and know how much to put back in. I actually pumped out 8.75 quarts not liters (fluid does not need to be heated...the 8.75 quarts come out in under a minute with the tranny at 180 at the beginning of the procedure). I think your question is how do you know when to stop the truck..... Well that depends on how hot you can get your transmission prior to the flush because it affects the internal thermostat which controls the flow of the fluid. To answer your question more specifically....get your tranny as hot as you can (I got mine to 180)...When you begin the flush the fluid will sputter just before it starts to flow...this is normal. The flow will then be steady and flow freely....as soon as it begins to sputter again/see air or as soon as you have pumped out approximately 9 quarts (whichever comes first) have your partner shut the truck off. As stated the rate and amount of fluid that gets pumped out depends on how hot you get your tranny. If for some reason during the procedure you didn't get the tranny hot enough and only pumped out 5 quarts and it begins to sputter...shut the truck off.

*Important...don't forget to add 10 quarts after you drain the pan to get ahead of the pump...and don't forget to add fluid at the same rate (or as close to the same rate as you can) as the fluid is being pumped out.

 

When changing the internal filter, is there a gasket required for the pan? I didnt see it in the write up.

 

The transmission pan filter is re-useable. If your transmission takes Mercon SP, it is only available from Ford.

 

Sorry guys, I ment to say the transmission pan gasket is re-useable.

 

so ur saying while the truck is running and draining the fluid u have to add it back quart for quart while it is draining?? u cant just drain the 9qts then add it back once u shut it off??

 

WishIhada7.3,

Yep you have got to add it back while you are doing it or the pump will run dry before you get all the old fluid out. The pump has to have hydraulic fluid to pump, it cannot pump air.

 

Not entirely true. I get mine from Diesel Filters Online, which is a sponsor here. I just got my shipment in tonight. $60 and change for 8qts of SP and a external trans filter with o-ring. I agree with the initial 30K tranny flush, I did mine using Bear Hunters method. After completing the initial flush, and looking at Jeff Cooks tranny fluid analysis from Blackstone, I settled on changing the external filter and the pan fluid 7-8 qts depending on how hot the fluid is when draining every 15K. Internal "paint screen" filter ever 60k. Which I will be changing this time around, and inspecting the pan for debris.

 

 

Yes, I flushed it at 30k using Bear Hunters method. That is to get the initial wear material out of the transmission via a complete fluid change. After looking over Beechbumcooks blackstone report on his tranny fluid. i decided that I will just change what comes out of the pan every 15k and change the external filter as well. SP is a fully synthetic fluid, and Jeffs sample would have no doubt went twice as long. FWIW, many Ford dealerships DO NOT flush the tranny at the 30k service, they simply drain the pan. SOme change the external filter, others don't.