Thanks. That sounds like the ticket. Do this cold? Or would operating temp be OK? I guess If I have cheap fresh fluid on an I/V pole and flowing down the fill tube, it should be ok. My sister ran her Aspen SE super 6 dry of trans fluid and it was never the same. Ever since, I'm a "half full or no less than half full" when it comes to trans fluid. Too much fluid blew my trans in my 76 Volare back in the 80s.
You can do the initial pump out cold. Unhook the pressure side cooler line and put it in a large drain pan. Crank the car until there's no more fluid coming out. This'll pump out the converter, too. Fill with the cheap fluid of choice (Dex/Merc will work). Then treat it like a normal service. Run it to temp, shift through the gears, etc. Then repeat by pulling the pressure side cooler line again, cranking the engine until it's all pumped out. Then you can pull the pan and change the filter without taking a bath. Refill with the superseded Merc V. (It's silly not to at this stage. With the exception of the 727 in the Dip [the Dip has Type F in it since it's a "built" transmission] I've changed every stock Mopar in the family over to AFT4 and every Ford over to Merc V. The old man is saying the 270,000 mile old trans in his '92 Aerostar has never shifted better since the switch.)
If I remember rightly there's a band adjustment for the OD on this transmission. Check out an FSM if you can.
Don't worry about running the trans dry doing this. If anything you'll only be running it for a few seconds at the "dry" stage and over the years, the clutches and bands are soaked enough not to take damage after a few seconds. If you're really worried about it, have your buddy hang in the window and have him shut it down when you see there's no more fluid coming out.
Just dropping the pan will only drop out about four or five quarts. How much bad fluid is left in the lines, the cooler, the converter? Kind of useless to refill with four-six quarts when there's another six or so of the old crap still left in the trans.
I've been doing this for years in my own shop. I never had the money for a "flush" machine (which circulates new while pulling out the old). Believe it or not, this is actually in the FSM for Hyundai as most modern Hyundai transmissions don't have a pan, just a drain plug which only allows for four quarts to be drained out, with another 8 quarts left behind.
And cover your own ass on this. Let your buddy know this is only a shot at keeping the trans. After so many years of neglect and the fact the trans was having issues before, there's a better than 50/50 shot at having to replace the trans sooner rather than later. But, hey, spending a few bucks on new fluid and filter is worth the shot compared to automatically (forgive the pun) assuming the trans is done and spending the money on a good used one or rebuild.
I swear, most of the transmissions I've ever rebuilt were done simply because of neglect. Everyone remembers to change his or her oil every 3000 miles, but no one thinks of a trans service every 30K. Nope, don't think about it until the trans starts acting up then get in a panic because the car is now giving you issues.
And don't get me going on light truck and van owners who don't know how to tow properly.
