DIY'ing 7A trans fluid, need advice!
 

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.

First time, some of the trans fluid may have leaked out during use so you may need to refill with a little more than came out.
Second time, shouldn't be enough time for much leakage, so refilling with same amount that came out should work.

Perfect so is my process going to work okay? I'm gonna measure it down to the decimel. So if 3.7 quarts comes out and I fill with 4 quarts, drive for 5 miles or so and go through all 7 gears, then drain, re-measure and fill again with same amount, all while being perfectly level. I should be good to go?

Do you (or anyone reading this) think I should use a normal hand pump with a small tube to go all the way into filler hole? Or use a chemical sprayer? I've seen most all DIY'ers on here using chemical sprayer, I feel like the nozzle would be too big for the small filler hole on trans??

I'd get car level & remove 5mm overfill plug while running (un-warm) and let it come up to temp....you could be low on fluid without realizing it.
A tad may initially drop out,,,but it shouldn't continue with an overflow drip until it gets closer to target temp.

I used a chemical sprayer w/tapered nozzle...(pump up style).
you may have to re-pump reservoir to completely empty it.

Pic of mine.https://uploads.tapatalk-cdn.com/201...cc5c7ba736.jpg


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Only issue I have with that, is I live on a hill (not level) so I'll either be driving to my friends house w/ garage or to his work (shop with lift) so it'll be up to temp when I do it. And with it being 80-90 degrees outside, my car will take hours to get back down to "cold" or anywhere close to 104 degrees. So I was thinking just add a tad bit more than what comes out (i.e if 3.7 quarts came out, I'll add 4)
Second go around I'd like to make sure its accurate but again, that'll be after it's been driven 5 miles or so to get new fluids cycled thru all 7 gears. So it'll be warm again once I do it the second time. Any other tips? or ideas?


Ok cool . I found one at local Lowe's & Walmart ($10) , but not sure if it comes with tapered edge, did you buy that separately? Also what do you mean by "you may have to re pump res to completely empty it? The sprayer? Yes I will ensure it's free of ALL fluids cause I was an accurate amount put back in. So I will ensure all fluids are pumped from sprayer.

Yep=repumping the sprayer,,,you won't mess up-1/2 qt. either way until you can get a place & put it exact....one trans. builder actually allows fluid to drip until it reaches operating temp & then capping hole.

So I can’t just drain the fluid, reinstall drain plug, add a tiny bit more than what comes out, reinstall filler plug. And drive it and do the process twice to ensure all fluid is new?

I found a hand pump with multiple fittings. I’m gonna buy it $7 at HF and has plenty of small fittings that I can stick into the filler hole. So I’m just going to make sure car is level. Drain fluid. Add a bit more than came out with my hand pump and fittings. Drive it about 5 miles and go thru all gears. Return home and do it again.

Sounds good?

If its on the stands or a lift you dont need to drive it to get 104F.

Once refilled, I just jump in the driver seat and carefully engage drive and reverse to purge the air. Then I will carefully run it through M1 thru M6 at light throttle. Then park, reverse, drive then park. I use the brakes to simulate a load while going up through M1-M6. Be sure and stop the wheels before selecting drive or reverse.

By then I will check the temp and it will be 90 plus degrees. I just leave it idle in park, unit it hits 100F. Then I pull the overflow plug and watch for fluid to come out - as the oil temp increases. Once it hits 104-105 I plug the overflow port.

Lower the car and go test drive it.

Are you doing this when car is “cold” ? I will be driving it to where it’s getting changed because I HAVE to. Not b/c I want to. Lol. So when my car is at my friends shop on lift. It’ll be well over 104 I’m sure. I was going to just add a tiny bit more than what comes out, and then drive it to go thru all gears, and repeat process a second time to ensure most fluids are new.

Please explain your exact steps , TIA

When you remove check plug (5mm allen) be sure that car is idling & level,
the difference in cold vs.hot would probably be a maximum of 8-12oz.
only driving a short while will put it near ck. temp (by mfg.)...I overfill mine while cold & let car idle till it comes up to check temp before plugging.
Just don't try to check fluid level with car turned off,,,you'll get wet.

I’m really trying to avoid doing the whole 104 degree and check. I’d really like to just drain, fill back a little more than what came out, drive it, and repeat process a second time to get most all old fluid out.

you know if you just took it to the stealership and paid $100 you'd be done already.......

just syain lol