How To: Change Transmission Oil/Filter/Pan Gasket

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alexf20c
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Yes those are the correct bolts.


740fizza
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A couple of notes from my side having just done this recently. On 4WD models anyway, towards the front side of the pan, there are two clips holding in a couple of hard lines, going into the transmission. These clips need to be moved out of the way in order to drop the pan. The problem is they rust quit badly on the side which connects to the hard lines and these cheap bolts have a tendency to have their heads snapped off rendering them useless. I was lucky and loosened them up just enough to swivel them out of the way. The tricky part is putting them back in and getting the front bolts started, it's very easy to cross thread the front pan bolts since it's so tight there. After alot of messing around and cursing I got all but one of them back on w/o cross threading. And as far as I can see, you can only really use an open end wrench on some of them since it's so tight.

740fizza
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Lastly, I used Castrol high mileage ATF and shifts are fine, not much different then before but then again I didn't really have any issues. To be honest, I really question the need to drop the pan. At 91k miles, the filter was clean, magnet was barely gritty, no major particles. Had I known, I would have just swapped fluids. Besides, these arn't "real" filters anyway, just cheap-o metal screens.

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Towncivilian
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Would a neoprene gasket be any better? I read on a Dodge minivan forum that they don't require RTV sealant, is that true? I have a Beck & Arnley filter/gasket (same as recommended by Empty V in the first post) and was going to use that, but if a neoprene gasket doesn't need sealant I may as well purchase one for a couple bucks. But then again, I've got sealant already...

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Empty V
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Towncivilian wrote:Would a neoprene gasket be any better? I read on a Dodge minivan forum that they don't require RTV sealant, is that true? I have a Beck & Arnley filter/gasket (same as recommended by Empty V in the first post) and was going to use that, but if a neoprene gasket doesn't need sealant I may as well purchase one for a couple bucks. But then again, I've got sealant already...
Why would you need a sealant? That's what the gasket is for.

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Towncivilian
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Empty V wrote:
Towncivilian wrote:Would a neoprene gasket be any better? I read on a Dodge minivan forum that they don't require RTV sealant, is that true? I have a Beck & Arnley filter/gasket (same as recommended by Empty V in the first post) and was going to use that, but if a neoprene gasket doesn't need sealant I may as well purchase one for a couple bucks. But then again, I've got sealant already...
Why would you need a sealant? That's what the gasket is for.
Eh, guess I'll not bother with sealant then. Though how will I make sure the gasket stays in place while I'm trying to reinstall the pan?

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Towncivilian
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So I did this job with a buddy earlier today.

I used 5.5 quarts to re-fill. I drained about 5 quarts via drain plug and pan combined and used a bucket to measure it. I guessed around a quarter of a quart lost to drippage and fluid stuck in the filter. No idea why the first post said 7 quarts, unless I did something wrong :confused: IMO it's rather difficult to read the dipstick. Do I pull it out, wipe it off, then insert it all the way or just until the rubber stopper hits the metal clamp thing, then read that? I did have to add another quarter of a quart after reading the dipstick after I let the car idle for several minutes then shifted through all the gears and revved to ~1750-2000 RPM; it seemed barely above the "low" thatched section of "HOT". I'm almost certain there's enough fluid in there right now though as I filled at least as much as I drained if not slightly more, but it never hurts to make sure.

My pan's magnet had some sludgy black stuff all over it, along with a fair bit of metal fuzz. Glad I cleaned that off. Filter looked ok, just some small metal flakes visible in the screen, and its exterior was dark grey with dirt or something as can be seen in the first post in one of the pictures (I thought it was painted grey, heh). The fluid was pink on the dipstick pre-change, but during draining and in the pan it reeked pretty badly as old PSF would. It also looked rather brown as I was pouring it into a recyclable container; I did not smell the fluid to check if it smelled "burnt," however. This change was done at 120,340 miles; no idea whether transmission fluid was changed before.

740fizza, I had no issue with removing those brackets (hooray for Florida), but I forgot to reclip them when reinstalling the pan! Also, I noticed that the two pan bolts that hold those brackets are slightly longer than the rest; Nissan just gave me 18 of all the same size. Unfortunately I absentmindedly disposed of all old bolts. The lines in question are supported by brackets on either side of the pan too, so is it really necessary to go buy two slightly longer bolts and install these brackets?

I did use gasket sealant (not that gasket-in-a-tube stuff) on the pan itself, then stuck the gasket on and aligned it with the screw holes. I guess it stopped the gasket from sliding around too much while my friend held the pan up, but maybe it was completely useless. Hope the sealant won't cause any issues.

I was unable to find the torque spec for the pan bolts themselves in the FSM, so we tightened the bolts hand-tight with a socketed screwdriver then until resistance was felt with a ratchet. No idea whether I torqued them too much or too little (if anything, probably too much). Does anybody know the correct torque spec? I suppose if there are no leaks I won't have an issue. Not only that, but we had to back out a couple bolts that were cross-threaded, which made the orange sealant flake off. I assume that if one of those bolts causes a leak, I can just buy a new bolt and swap it out? Though I think that if the gasket seals properly the bolts won't be an issue; I've read that people just clean and re-use the old bolts. I tightened the filter to just before I couldn't tighten anymore, after cleaning off the four bolts with brake cleaner.

The entire process took us about 3 hours to do. We didn't ramp or jack up the car, since I could fit under there easily (I'm rather small), though my friend didn't have such an easy time. We still got the job done, though. I think if we had ramps it would've been somewhat quicker since there's more room to work with.

m0nkeyprince
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i finished this today, using 6 quarts of RP max ATF. 7.5 quarts is for the ENTIRE transmission, including the torque converter, so when you drop the pan, only about 5.5 quarts (estimate) come out. too bad i put in 6 quarts before i realized that, i too saw 7.5 quarts in the MA section of FSM. Hope that wont cause the ATF to run out of the dipstick tube and catch on fire. :P

i reused the bolts, i thought the orange stuff was loctite red my last mechanic put on when he did the ATF change. i just cleaned and reused the bolts, i too had a problem with 4WD bolts, having one of the hard lines bolted to 2 of the bolts, making it difficult to unscrew, but with persuasion, its possible.

When i was cleaning the pan, i had hideous black goo covering the magnet, and a bunch of lines and parts behind the ATF filter. The picture of EMPTYv's old ATF filter is blackish grey right? well all that black color can be wiped off!

Finally, i too did not have the torque specs to the pan bolts so i just tightened them to the point of minimal resistance then i stopped. i noticed tightening too much causes the edge of the gasket to be squeezed out a little.

Joe99qx4
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i have a 99 qx4 and I was wondering if anyone else has noticed the tranny behaviors I have and did changing the fluid/filter help with this.

1. Hard shift from 1st to second gear only. All other shifts are smooth. Seems to get better when engine warms up.
2. Delayed or slow shift from second to third. Almost like a slip, but more of a slooowww shift.
3. Tranny dosen't down shift from 3rd to second. I can decrease speed to about 15 miles per hour and she is still in 3rd gear.. if I hit the gas pedal harder, it then jumps down to second gear. It should downshift on it's own per the speed you are going, right?

My fluid has been changed before, by just draining the fluid and puting new fluid back in, but I wonder if the filter is clogged, causing the pressure in the tranny to be lower then it should. Then again, I think someone above said this is not really a filter, but more a strainer..so does this mean that it's not really possible to clog up a filter like this one? I have no problem doing the filter change; I think this one is easy compared to other cars that don't have a drain bolt and oil gets all over the place when lowering the pan.

My Q has 130,000 miles on it. Fluid was changed about 15,000 miles ago. Fluid looked good before I changed it, but thought it wouldnt hurt to change it again... I have owned the q for about 3 years. It has always done what I explainaed above and it's has not gotten any worse or better.

Joe.

m0nkeyprince
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Joe99qx4 wrote:i have a 99 qx4 and I was wondering if anyone else has noticed the tranny behaviors I have and did changing the fluid/filter help with this.

1. Hard shift from 1st to second gear only. All other shifts are smooth. Seems to get better when engine warms up.
2. Delayed or slow shift from second to third. Almost like a slip, but more of a slooowww shift.
3. Tranny dosen't down shift from 3rd to second. I can decrease speed to about 15 miles per hour and she is still in 3rd gear.. if I hit the gas pedal harder, it then jumps down to second gear. It should downshift on it's own per the speed you are going, right?

My fluid has been changed before, by just draining the fluid and puting new fluid back in, but I wonder if the filter is clogged, causing the pressure in the tranny to be lower then it should. Then again, I think someone above said this is not really a filter, but more a strainer..so does this mean that it's not really possible to clog up a filter like this one? I have no problem doing the filter change; I think this one is easy compared to other cars that don't have a drain bolt and oil gets all over the place when lowering the pan.

My Q has 130,000 miles on it. Fluid was changed about 15,000 miles ago. Fluid looked good before I changed it, but thought it wouldnt hurt to change it again... I have owned the q for about 3 years. It has always done what I explainaed above and it's has not gotten any worse or better.

Joe.

i notice number 1 constantly, from 1st to 2nd jerks if you let go of the gas right before it shifts, trying pouring a can of sea foam trans tune, it helped until i changed the transmission fluid to RP MAX ATF 10 miles later

740fizza
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TownCivilian - All of my bolts were the same length as well so I don't think you will have an issue. As for torque, I used the good ol' German "goood-en-tite' specs :)

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Towncivilian
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740fizza wrote:TownCivilian - All of my bolts were the same length as well so I don't think you will have an issue. As for torque, I used the good ol' German "goood-en-tite' specs :)
Thanks for that bit of info. I've got no leaks so far and the hard line I forgot to bracket back in is just fine, too.

I also notice that the shift from 1st to 2nd is rather hard (but still seems to shift faster than before) sometimes, but I believe that's just how the car is from what I've read. Everything else seems nice and smooth. Next time though, I'm definitely not paying through the nose for Genuine Nissan ATF.

Joe99qx4
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Did you guys see the posts about people changing or cleaning there MAF sensors and it changed how the QX was shifting? They called it a transmission flare, which I'm not really sure what that is. I purchased a $7 bottle of MAF cleaner and will clean my this week. The bottle claims that the MAF gets "stuff" on it that reduces performace, so even if it does nothing to the shift, maybe I'll get some HP out of it.

transmission-flare-update-anyone-with-t ... 11262.html

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G8rDuc
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Don't forget that not flushing the tranny makes this an incomplete job. This is why shops charge so much to do this. There's a lot of fluid in the convertor.

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donald
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ok - another question for this How-To :)

What is the Transmission code for between 4x4 and 2wd?
I found a tranny gasket and filter online, but it states "2wd". But I wasn't sure if they changed the pan between 4x4 and 2wd tranny or not.

Does that mean there are 2 types of gasket and filters out there?

m0nkeyprince
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if you get the wix filter, which is what i got, it comes with both 4wd and 2wd gaskets.

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donald
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Ok - so I guess there is a difference in transmission pans.
where did you get your Wix filter?

I found this on Amazon...
http://www.amazon.com/gp/product/B000C9 ... PDKIKX0DER
but it only shows 1 gasket.

I did find this one though...
http://www.amazon.com/Hastings-Filters- ... &carId=023
which does show 2 different gasket types. I'll need to slide under my truck to see which gasket lining-patterns it follows.

By the way - did anyone use gasket sealant or liquid gasket to the tranny to make sure no leaks? Advisable?

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Towncivilian
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I used some gasket sealant to help the gasket stay in place while buttoning it back up, but it probably didn't really help much. Not knowing the torque spec, I probably overtightened the pan bolts a little and the sides of the gasket squeezed out somewhat and the sealant is visible. No leaks, though, so...

m0nkeyprince
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if you reuse the bolts, a little thread sealer permatex might help. I didnt though, but it did not leak whatsoever without it. I got my wix filter from amazon. when you tighten the bolts back on, make sure you do not tighten them too hard, i couldnt find the torque specs but when you tighten them to the point where the gasket is squeezed out, thats wayy too tight. im guessing i tightened to near 12 ft lbs., not exact again, but the emphasis on not over tightening it is there.

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Towncivilian
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I've got no leaks despite the overtightening - is it worth my time to go and retorque them to something like 13 ft lbs? I'm gonna do a drain and refill soon cause my fluid still smells a little burnt, so I'll be down there anyway...

m0nkeyprince
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i think youre good, i mean if there is no leak, there is no problem. Thats weird how your new ATF would "burn" that quickly was the old fluid burnt?

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Towncivilian
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m0nkeyprince wrote:i think youre good, i mean if there is no leak, there is no problem. Thats weird how your new ATF would "burn" that quickly was the old fluid burnt?
Old fluid smelled really bad when it came out, but I don't think I ever smelled it to see if it was burnt. It looked pink on the dipstick pre-change, but looked significantly darker in a bucket. I did get stuck in the mud recently and I did put a lot of strain on the transmission - high revs in reverse and other gears. Maybe that's the cause. Nonetheless, $20 for some Valvoline Maxlife ATF from AAP after online discount is very cheap insurance! My PSF also smells a little burnt, and I did the turkey baster method using 3 pints of Genuine Nissan PSF (what a rip off) and for a while it smelled perfect. I don't know how that could have become burnt so quickly either, but $9.78 for a gallon of Valvoline PSF (vs. something like $8/pt @ Nissan) is also cheap insurance.

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Towncivilian
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MY1PATH in this NPORA thread says the torque spec is 5.1 - 6.5 ft. lbs. (61.2 - 78 in. lbs.), and I'd say I tightened my pan bolts probably significantly over that. But I guess it'll be ok since I have no leaks, and if I ever drop the pan again I'll be replacing the bolts anyway... will do drain and refill of ATF tomorrow and post results here.

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Towncivilian
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I found the torque spec for the filter and the pan bolts:

Image

This is from the 2001.5 FSM.

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Towncivilian
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I have revised the first post slightly, adding OEM part numbers and an aftermarket filter/gasket kit option, as well as torque specs for the filter bolts and a corrected drain plug torque spec. I also added recommendations for adding an in-line Magnefine transmission filter, as well as other fluid exchange options (a simple drain and fill, or cooler line fluid exchange) at the top of the post.

elkootcho
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the link to the aftermarket filter kit states "4WD"... is this also good for 2WD?

http://www.rockauto.com/catalog/raframe ... um=0440221

Qxx4
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Hey guys nice write up, tommorw i will be changing my tranny fluid with its filter but i cant seem to understand how my liters of oil do i need in the service manual it written 8.5l and some here wrote 3,5l and others 6l i am a bit confused can someone please explain :confused:

AlanAZ
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Towncivilian wrote:... I also added recommendations for adding an in-line Magnefine transmission filter ...
Will you, or Empty V, please change the Magnefine size in the first post from 3/8" to 5/16" for 2001.5 - 2003 QX4/Pathfinder. The 3/8" filter connectors to be too large for the hose, I got it on after much work, but barely, and not to the end of connector. According to 'atraudes', the 5/16" fits perfectly. Thank you.

If you do install Magnefine filters, be aware they recommend changing the first one at 15K mls, after that, 30K mls.

attofarad
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I personally wouldn't bother to drop the pan for a fluid change, unless you need to fix an existing gasket leak, as I did. The filter is more of a rock catcher than it is a fine filter -- mine had nothing visible at all in it at all, at around 150k miles. If you don't know the history, and want to change more fluid, just drain/fill a couple of times, either after a short drive or maybe a week or month. After that, a drain/fill every 30k is what I do -- which is an overkill since I don't tow with it. I use the Castrol Import fluid.

Blindaviator
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^^^ What Attofarad said...

The "filter" in the pan is nothing more than a strainer to catch objects the size of BB's... I learned this the hard way when I changed mine a while back.... Was a lot of work for not needing to do it...

I guess it's why they recommend adding an inline filter to the cooling lines...
Add in a Magnefine filter to the cooling return line and your golden...
http://magnefinefilters.com/


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