DIY'ing 7A trans fluid, need advice!

AstatenateZ

Ok, so I am a DIY'er and consider myself fairly mechanically inclined. I made a post a couple weeks back about having my friend at Nissan doing my 7A full flush for me. Upon further inspection the Nissan and all local Nissan's in my area for that matter do NOT have an exchanger machine for trans fluid and they'd be forced to use a hand pump (only the CVT's with dipstick are able to use the exchanger machines) I was only going to pay one of my Nissan tech buddies to do it when I thought they were using a machine that would pump ALL fluid out.

My buddy also told me there was a "special" charge pipe that needed to be used and no local stores have one as they haven't serviced 7A tranmissions. So with it being his first time, not using the fancy machine, and using a simple hand pump with a special charge pipe. I figured why not do it myself? As well as the fact that if he's just draining the 2-4 qts that come out of the pan there'd still be roughly 1-3 qts left in tq converter and valvebody. So he'd have to do it 2-3 times before its fully "new" fluid in trans... so again, why not just do it myself???

After much research and reading many posts on here of people DIY'ing I thought I'd ask some advice before I tackle it, I got a print out from Nissan of how to do it, the temps to check at (104 degrees) and whatnot.

Basically I have purchased 10 qts of S Matic, I have both a hand pump and a chemical sprayer to pump new fluid in. I can easily get my hands on infrared and measure trans pan for the 104 degree sweet spot. But here's my question... Can I just pull drain plug, measure whatever comes out and simply add that back in with fresh fluid?


My plan was to put car on lift, drain the fluid (i.e 2-4 qts) , replace drain plug, while at the same temp as when drained, add 2-4 qts back (however much comes out) and then drive in manual mode thru al 7 gears for a few mins and repeat process a second time to ensure all trans fluid or at least 90% of the fluid in trans is fresh?

Any advice, tips, on my second time filling trans should I use the infrared to measure tran temp and wait for it to overflow and drip out? Or will my way work? Any advice is appreciated.