Mad Irishman

Its time to change the fluid on the diff's and tranny. Local shop says all they do is back flush the tranny and no filter change. Is this acceptable or should I wait until I can drop the pan myself and actually change the fluid and replace the filter?

Rick's 06

There are different opinions on this and pros and cons either way. If the shop does the trans fluid change, they should be able to change all the fluid which you can't do with a pan drop. But they won't do the filter or clean off the magnet which are important in my opinion. I'm assuming they don't really back flush the system since that would run fluid back through your filter and force out all the shavings that it has captured. That would not be good. If your truck is new or newer, I'd probably vote on dropping the pan and changing the filter. Then drop the pan at regular intervals to change out the 5 quarts you get out. Some have installed a drain plug in the pan to make this chore a lot easier. For what it's worth, that's what I do.

MGD

Hi.

Shop's full of ****. You can't backflush a 4R70/4r75 - fluid will only flow in one direction.

Best method - find a shop with an exchange machine - these use the trans pump to pull in new fluid while expelling the old. Specify that NO cleaning chemicals are to be used.

For completeness - drain the ~5 quarts from the pan first, clean it & the magnet, change the filter, button it up, add 5 quarts of fresh fluid, then perform the exchange. That is the most complete method. It uses almost 20 quarts of fluid.

good luck
MGD

60DRB

Either of the above. I do as Rick.

dm396

I just finished installing this. It was a pain, but should make regular maintenance a lot easier in the future. and besides, it makes me much happier than the lame plastic pan.

new ppe heavy duty aluminum pan installed on 2018 f150. note the nice drain plug.

F150Torqued

I agree with MGD. Being a 'cheap skate' (and more than a little 'Red Neck'), I got as close to this as can. I dropped pan, cleaned magnet, replaced filter then added 4 Quarts. Disconnected the trans cooler line at the radiator and stuck it into a 1 gallon clear jug (Milk Jug). Crank engine and let idle till the milk jug was full (somewhat less than a minute) and shut it off. Emptied the milk jug, added 4 more Quarts and did it again ---- UNTIL what was going into the milk jug was 'pure, clean, fresh' fluid. Took about 17 quarts total. Then reattached the coolant line and checked fluid level (was close enough). I had bought 18 quarts thinking I would spill some - but it actually didn't spill ANY on the driveway.

I figure it was as good as machine exchange except for the extra quart or so I ran before deciding it was expelling good clean fluid. I think it worked very well.

Rippedsquad

i did mine but didnt realize that the small check valve got clogged up. my tranny was overheating and i couldnt figure out that that was the culprit... tool 3 months of guessing cause it never threw a code. the fan clutch would just blast like a jet engine,
id like to pass on the blame to the shop that installed the rebuilt jasper tranny into it 30,000 miles before i bought the truck.
i figured they would have replaced the lines and the check valve along with flushing the cooler when installing a new unit...

Eric Kleven

^^ I had that same kind of overheat problem. I got a new "check valve" (thermal bypass/thermostat). Couldn't get the rusted lines to move, so I used a big C-clamp and some snap-ring pliers to swap the new thermostat guts into the old block. It's been fine ever since.