904 flush and fill service question

I have a 93 dart with 125k shifts well but has some leaks and is going through some trans fluid.
I was reading in the Mopar website about the Torqueflite and it said if the tranny has over 50k dont even think about a flush and fill because chemical differences between saturated clutch plates and new fluid will cause a failure on the plates pretty quickly.
I also want to address the leaks but have not run them down yet figure mostly likely old rubber and work seals.
Any thoughts on flush and fill and performing a in-place seal replacement?
I see a "Torqueflite 904 External RESEAL Kit '60-63 With SLANT 6"

http://www.ebay.com/itm/370539322527?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

Thanks for your input,
John

Buddy owns a trans shop, you mention a flush around him you better duck. I do know he does get work rebuilding units that have been flushed.......

Drain and fill will also put 4 or so quarts of new fluid into an old trans. So even if you change a leaky gasket you're going to get a good amount 1/3 to 1/2 of new fluid into the system.

At 125K miles on a transmission is a lot of miles to introduce all new trans fluild into the system.

Many trans shops use a power flush apparatus. It's air powered and pushes fluid through the lines with the car not running. Mostly used when a trans blow metal chunks or a trans to radiator cooler leaks radiator fluid into the trans.

Modern transmission fluid exchange machines operate with the car running with the transmission naturally pumping fluid through it. These machines let the transmission pump fluid out of a cooler line and then put new fluid immediately back into the transmission at the same rate and amount. The level of the trans fluid will not change much during the whole process. Like a blood transfusion.

If you need to fix leaks you clean around the trans really good. Probably high pressure self serve car wash jacking the front end up. Clean around the dipstick tube seal, shift shaft selector seal, trans pan, cooler line connections, inside bellhousing (front seal), and rear tailshaft seal. Then see (or repair shop see) where it is leaking from looking at those locations.