I had mentioned in another thread about how I have an oil leak either coming from the rear main seal or oil pan gasket. I have a 2 wheel drive F150 and know about the whole lifting the engine a few inches to get to the oil pan gasket and also removing the transmission. I had recently replaced the transmission filter and replaced the 4 qts of tranny fluid that were darker but ONLY in the pan. I think the auto 4.2 takes 14 qts and wanted to ask should I flush out the rest of the tranny fluid or wait until I fix the oil leak? Truck has over 201k on her now and I want to keep her until the wheels fall off and don't want to replace a transmission. So basically I have about 10 qts still in the torque converter and throughout the tranny. Truck is fine with shifts and runs great but I realize that could be an issue if I don't get the rest of the old tranny fluid out.

 

I would wait until you remove the tranny to replace the rear main seal. That way you can simply pull the converter off the front of the tranny and drain as much fluid out of it that you can. Then drop the pan to get all of that fluid out. Doing that will cut down on the amount of fluid you need to flush the tranny.

 

Thanks Alloro for the advice! That is what I figured. Trying to make this as painless as possible plus keeping cost to a minimum.

 

Well I figured I would call around to get some estimates on a transmission flush and got some interesting opinions. Tire kingdom $129.99 and a place I have done repairs at before $150+. I ended up calling AAMCO and they said they would not touch it after 140k miles. I was told that the 4.2 should last about 350k miles and the transmission about half of that miles. Has anyone else heard of a shop agreeing to that? I thought it was the most absurd thing I have heard of turning business away because of miles. Transmission shifts fine and motor is ok except for the oil pan gasket/rear main seal leak.

 

Just got off of the phone with Tire Kingdom and they said they would not touch the transmission after 100k miles. I was told that changing out the tranny fluid in the pan was good enough along with the filter change like I had done. Risking putting in the 10 qts to the Torque Converter might cause more harm than good with the tranny flush. They said they had a customer who insisted on having the tranny flushed and the truck had problems slipping after it was done.

 

That's a bunch of BS. New fluid in a good trans will NEVER hurt it.

Where they are coming from is that many (most?) people don't do any maintenance to their transmissions. When it gets high mileage they start to notice problems and realize that they should have changed the fluid. Now they get the fluid changed and the trans fails shortly afterward. The new fluid couldn't fix the damaged parts from all those miles of neglect. If they hadn't changed the fluid the trans would have failed, too.

 

Originally bought the truck with 117k on the clock.
I do ADMIT I didn't change out the old tranny fluid until about 150k-170k miles but just in the pan. To that point the tranny had NO ISSUES and was shifting fine and still is. When I dropped just the pan to replace that fluid along with the filter I noticed the yellow little piece that Ford puts in at the factory for the dipstick. Now the fluid was dark but not burned in anyway. Now knowing that these places obviously will not touch it I am concerned if I replace the other 10 qts in the Torque Converter

 

 

Well finally got around to flushing out the old tranny fluid and adding new Mercon V. Took me several hours as I had some issues with taking off the return tranny line and also putting on the 3/8 " vinyl hose. It was pretty straight forward using the hose and draining the old when I started the truck. Dropped the pan once again and replaced the filter. No medal shavings which is great. What a difference driving it last night. Shifts are more solid and no drag. Now hopefully the tranny will last another 100k miles. Here is the link to this great how to to do this: https://sites.google.com/site/fordf1...nge-procedures