Trans Fluid/Filter Change?

1996 Z28 Automatic, 75k miles, doing a transmission fluid/filter change,,
Question: Should this be done professionally at shop, & should we choose a shop that will drain torque converter as well, I would think its important to drain converter to get all old oil out?

If we do fluid/filter change in back yard, there is no way we can drain all transmission oil, correct?

Thanks for any input and advice,

 

Most places just drain the pan, and refill.

The correct way to get 100% fluid change would be to:

Drain fluid from pan (about 4-5 qrts)

Remove pan and change filter

Reinstall pan

Add the same amount of new fluid as what came out

Disconnect the fluid line that goes from the transmission, to the tranny cooler (mounted on/near radiator, disconnect from tranny side)

Start engine (fluid should be coming from disconnected hose, if it is coming from the tranny, reconnect hose, and disconenct the other)

Pump out about 1 qrt into a clear bottle, stop engine, and replace that 1 qrt with new.

You will do this about 5-6 times depending the capacity of the TC. You want to do it until the fluid coming out of the hose is nice and red.

This procedure will ensure 100% fluid replacement.

 

This is always a hot topic here, so I'll add my $.02 worth - replace fluid and filter at the recommended "severe service" interval and don't lose any sleep over it. The last tranny in my wrecker went about 300,000 miles and was never "flushed".