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

I have done that on other cars. But, you can pick up an infared laser temp gun at OReilly or other autoparts stores for cheap.

Just shoot the trans pan with the laser in 3 or 4 places with the car level, to get the temp, and fluid level correct.

Here is my experience with fluid change on the 7at:

I used Assenmacher ATF 180 adapter, fluid hand pump and IR thermometer of Amazon.
I dropped the oil pan and swapped it for another one that I bunged temp sensor and defi gauge into so I can monitor my tans temps at the track so that's how the fluid was drained. Then the mechanic filled it and drained it 3 times while the engine was off. I drove for awhile and noticed the car jerked when I came to stop from a hard braking. Obviously, the tranny was low on fluid because when it was filled the torque converter was at a standstill. We redid the procedure, however, this time the car was already at operating temp (fluid at 80-90C). Left the shop and still had the problem which indicated that I was still low on fluid. The third time I parked the car at the shop at night so it would cool down and started working on it the next morning. Turned it on, put it on the lift while running in neutral, pumped more fluid till it was full closed the fill port, monitored the pan temp with an infrared thermal gun of amazon till it reached about 35c that's when we reopened the fill and refilled it till it started dripping all while cycling through gears (5secs in each from P to D), when the fluid started to drip we closed the fill port.

What I learned:
*Trans fluid is affected a lot by temperature. I remember seeing a graph somewhere that showed the volume by the temp of the fluid. You should start after your car has cooled down.
*The car has to be relatively level.
*The cycle of filling and draining 3 times is mainly done to guarantee the fluid was completely changed everywhere in the tranny not only the fluid in the pan.
*Fluid temp in stock 7at almost matches the oil temp. I have 25-row Setrab 6 series on my car running with the stock in-radiator cooler and my fluid runs about 15-20c cooler than my engines oil temp. So at the track, I pull off when my oil temps are high and I don't have to worry about my trans fluid.

Sorry for the long read lol hope it helps

Here is a good read that helped me

https://www.myg37.com/forums/d-i-y-i...rop-clean.html

Also, download the service manual check part TM page 316-318

May take more than 2 exchanges before the fluid looks clean.
There is no way stealership is only going to charge $100 for this.
I have a vacuum pump and a 4"x48" ABS pipe with caps on both sides as reservoir. That sucker can hold a lot of fluid.
and... have not done this on a Z (mine's a 6-spd) but have on other vehicles.

Did you read my post? Lol my dealership has never done one. I have a tech friend at Nissan who said no one there is comfortable doing it and it hasn’t been done. They can’t hook their exchanger machine to it. So they’d be using a hand pump (same thing I’ll be using) and lastly they don’t have the part to do a fill. The charge pipe or whatever it’s called.

ah gotcha i missed that tid bit. my bad.

Ok talked to my mechanic friend who’s house I’m gonna do it in, I'll do the initial drain and fill with slightly more than what came out. Drive it to get fluid in all gears. And then when I drain it the second time, I’ll let it cool off, I’ll add what came out, and measure trans temp with infrared (he said he has one) and then as soon as it stops overfilling out of the drain plug at 104 degrees it means it’s at the proper level? Or once is stops overfilling out of the filler plug at 104 degrees it’s at properly level?


Okay I’ll do the initial drain and fill up with tiny bit more than what comes out. My second time doing it, I’ll let car cool off. Drain again and fill up. Until it flows out of drain hole or filler hole at 104 degrees???

http://i1383.photobucket.com/albums/...ps9ovqriox.jpg

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This is the info I have. I guess I will measure temp (on the second drain to make sure it’s proper)


So my new list is 1) jack car up, get level
2) drain fluid and measure what come see out
3) add new fluid (slightly more than what comes out)
4) drive it thru all 7 gears.
5) come back , jack it up level again
6) let it cool off
7) drain & refill what comes out
8) hit trans pan 3-4 places with infrared gun to check til it’s between 95-113 degrees roughly 104 degrees. Once close to 104 degrees I’ll unplug filler plug and once it starts to barely drip out at proper temp I’ll reinstall plug (like I did with my rear diff) and go test drive it.

Am I good on this?

No prob it was kinda long I didn’t expect everyone to read ALL of it lol

yeaaaaa i saw multiple lines and just said nahhhhh i get the idea here lol

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I’ll be using this type of hand pump!

I'll try to break it down into steps

1. Start with the car while its cold. (if you have been driving it your pan will be too hot and won't cool down and you won't be able to know when to drain in the last step)
2. Lift it, turn the engine off, drain fluid through the drain plug. Close drain plug
3. Fill through the fill port about 3 liters, close the fill port
4.Turn engine on while car STILL on the lift. (No need to drive it)
5. After 3 mins, turn the engine off. drain through the drain port. close drain port.

6. repeat step 3 to 5 (fill again with 3 liters, turn the engine on. wait 3 mins. engine off. drain)

7. Finally 3rd fill; fill 3 liters. turn the engine on keep filling till fluid comes out of the fill port. close fill port. go through all gears while waiting 5 secs in each gear. Shift to P. keep engine running. check the oil pan temp. when it reaches 95F. reopen the FILL port NOT the drain. fluid will pour out. when the fluid stops pouring and starts dripping close the fill port you are done.

That's why it's important to start with a cold car if you just drove to the mechanic your pan and trans will be hot even if the fresh fluid in it is not and you won't be able to do the last step.

Summary: Drain old fluid. fill and drain twice. you fill 3rd time. adjust the fluid level through the fill port at the right temperature. while the engine is running.

If you have questions let me know

That all sounds good and like my plan. My only issue is I can’t do it at my house. So I’d have to drive it somewhere. So I guess I’ll just have to sit around and wait for it to cool off. I’ll use fans or something to cool it off faster maybe?

Also I wonder what the dealership does, whoever comes in for a fluid change would of driven the car to them? So it wouldn’t be “cool” either.

But anyways yes that sounds pretty spot on to my plan , I’ll just have to wait around at first for it to be cooled off.

I see. I didn't mention it but I had another attempt to adjust the fluid while the car was hot and I couldn't because the tranny and pan were already higher than the correct temp which caused me to drain too much.
Now, this is not a problem for the dealer because they use the Consult II, there is actually a trans fluid sensor that only the ECU can read and it's not accessible through OBD

Ok sounds good. I’m just gonna use common sense (drain and measure, whatever comes out, I’ll put back in, maybe a tiny bit more to be safe) the first drain.

Second time. I’ll let it cool to proper temp, drain, then between 95-113 (roughly 104) I’ll add until fluid starts to drip out of transmission filler hole and then I’ll replace filler plug.

Also @QTR can you tell me if it pumps in easily? Like if I have a fitting that goes up into the filler hole will it flow back out and down and make a mess? Or if I can get a decent seal will it go up and over the block off area and into the trans pan fairly easily?

Well from start to finish (with a pizza & drink break) and letting car cool off on jack stands for nearly an hour, I got it done in about 2 hours. I drained old fluids from filler hole then drain plug while at 110-120 degrees , I got about 3.7 qt out. I put in 4 quarts my initial run. I put the car in each gear waiting 5-10 seconds while in each one, I put the car in drive for 2-3 mins and just let the wheels turn and then went thru each of the 7 gears while on jack stands by applying brake for resistance. , drained (looked a lot better when it drained out this time) and did this Process again, I added about 5 quarts (1-1.5 too much to ensure I had enough) measure pan temp in 3-4 spots and I was between 95-105 degrees. Let excess pour out til it dripped and tightened all bolts on pan. Took it for a drive. And feels much smoother and no slips , noises or lights. Thanks everyone for the good advice and tips!

What did the fluid look like on first drain?


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Not as black as coffee but def not red. It was pretty dark brown, second time it was a very lightly brown mostly red and looked a lot better! Shifts feel smoother, & more responsive when using paddle shifters.

Agree with shift improvement,,,like giving it a tune-Up!
Though my fluid was dark-it didn’t smell burnt & every time I did the 4qt. Drain/fill afterwards,,,I would get the same feeling.
Just pick you out an interval that works for you,,,as these tranny’s do like clean fluid.
Next Z will get a cooler up front beside the oil cooler.
Now you see it wasn’t hard at all...(Pie-Job)

Yeah I’m a DIY’er and like the feeling of doing it myself. Only reason I even considered Nissan doing it cause I have a tech friend who was gonna do it for cheap and because I thought they’d use the machine and pump every bit of old fluid out.

Since they didn’t use exchanger machine and it’d be his first time doing it. I figured why not do it myself. Lol glad it worked out simple and easily and trans feels way better. Thanks again for the tips & advice! :tup:

I do mine myself as well and am doing it at 20k interval. Bought my car with 17k and did it at 20k and it was definitely dirty. I removed the pan and cleaned the magnets. I also added 2 bungs that I mig welded in. One for temperature probe and one for a better fill port. Basically when you pump fluid in this transmission the idea is to be under the car with it level and when you do the final fluid service, you are pumping it in and then with the trans at 104 degrees you will remove the overfill plug and drain off the excess fluid WITH ENGINE RUNNING. It's like checking a conventional transmission in park with engine running and warm except instead of a dipstick you are using the standpipe in the pan to set the fluid level. I did mine with engine off the first time by mistake and the car shifted funny. After rereading the maintenance procedure from alldatadiy I realized it had to be running and I was about 2 quarts low. Also my trans temp gauge matches what I measure with my Harbor freight laser gun within a few degrees on the pan surface