DIY 2012 Civic Si Manual Transmission Fluid Change

momo said:
so..do you use the bolt next to drain bolt to fill it up? or the way described in the DIY?
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If you look at the picture below, where his finger is pointing is actually the bottom of the transmission. The bolt circled in yellow is near the top and the one you want to use for filling.

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My take and experience on this. I just did this for the first time at 49K miles. No issues with the transmission to note before doing this. While looking at the bottom of the transmission while the car was up on ramps for an oil change, the first thing I saw from below is the filler bolt on the side of the transmission is tucked up in a hole surrounded by the sub frame. The bolt hole has a good chance of making a mess in the whole area and the only real access is from the wheel well, with the tire off. You could probably work on it underneath using the room around the tire and the wheel well to take the bolt off and re-torque but it seemed to much of a PITA without taking off the wheel. That leaves putting the car on a couple of stands in the front and then jacking up the rear to get it level and either holding there with the jack or a couple of more stands at the rear points. I'm only going to be underneath the front of the car at the time, so the stands will hold the front up in the event the jack takes a squat while holding up the rear end.

So I took a look from the topside to see how bad it is to use the upper fill bolt as the OP suggests. It's underneath the stock air box so you need to remove it to get good access to it (unless you have a non-stock option like the OP did and removal is not necessary). Removing the box is easy. Disconnect the MAF sensor on the top of the box and disconnect the snorkel hose. Remove the top and filter completely and set aside. Remove the single 10mm bolt in the front right and then pull the rear of the box up and free it from two aluminum studs. The rear of the box fits on the studs with rubber grommets. Just ease it off and don't jerk it up into the master cylinder. Now you will have a clear view of the filler bolt. Crack it open and leave in place to keep out any crap.

Go below and prep for the drain. Keep in mind the car is still only on front ramps with tires, the rear is still on the ground. Get a piece of aluminum foil, around 2 ft long and cover the subframe right beside the drain. Let half of it hang below the subframe and form it to angle the drain flow into a bucket. The foil keeps the mess at a minimum but mainly directs the flow into a bucket. Crack open the drain bolt and remove. It will come out slowly at first until you fully remove the top filler bolt to allow it to vent. Remove the top bolt and let it all dump into the bucket. Once empty, reinstall and torque the drain bolt. Keep in mind, I am not touching the side filler bolt, it remains installed. Remove the foil and everything is clean.

The bucket I used has volume markings so I observed 2 full quarts came out of the transmission. Right on the dot, two quarts. The fluid was translucent when it was draining out and I didn't find any crap or metal in the bottom of the bucket when draining it out. Draining the car at an angle has no issues.

So with 2 full quarts drained, I filled through the top with 2 full quarts of new MTF. No mess. No squeezing a bottle, pumping a pump or feeding through a funnel with a j pipe on the end to fill through the side. I put back in exactly what I took out and it agrees with the amount shown in the manual. Reinstall and torque the top fill bolt and reinstall the air box. Done, easy and no mess.

Another cool thing removing the top fill bolt allows you a peek inside the tranny. Everything looked new and clean. If you have one of those snake inspection cameras, you could see more.
 
Interesting to read that most people are using the fill bolt on the side with some type of special funnel setup.
This would lead me to believe that the top fill bolt is a new addition to the transmission and most people are used to doing it the "old way"
IMO it sounds easier to remove the stock air box and use the fill bolt on the top of the transmission. (less mess and you don't need a special funnel)
If you are paranoid about overfilling the transmission you could always level the car, unbolt the side fill bolt and pour the trani oil from the top until it starts to spill out the side.
I also like the idea of using the foil to stop the oil from getting all over the subframe. :thumbsup:
 
Just did this with @Nomar06 recently. We used the lower "fill" hole. It was pretty easy with a cheap fluid pump from auto zone. This one is like $10 and the cap screws onto a standard fluid bottle and then just slip the upper hose into the fill hole. Had to transfer the remains of the first bottle into the second to reach it with the pump but there was just enough in 2 of the quart bottles to fill the trans to the point it started dripping from the fill port. The short sections go on the bottom to reach into the bottle.

Break the fill port open first. If you can't get the fill port open then don't drain your fluid!

9016678_ptl_w1139_pri_larg.jpg
 
Nix said:
Just did this with @Nomar06 recently. We used the lower "fill" hole. It was pretty easy with a cheap fluid pump from auto zone. This one is like $10 and the cap screws onto a standard fluid bottle and then just slip the upper hose into the fill hole. Had to transfer the remains of the first bottle into the second to reach it with the pump but there was just enough in 2 of the quart bottles to fill the trans to the point it started dripping from the fill port. The short sections go on the bottom to reach into the bottle.

Break the fill port open first. If you can't get the fill port open then don't drain your fluid!

9016678_ptl_w1139_pri_larg.jpg
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So I'm curious @Nix, why did @Nomar06 and you decide to fill the transmission through the side and not through the top?
 
JonnyRotten said:
So I'm curious @Nix, why did @Nomar06 and you decide to fill the transmission through the side and not through the top?
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The side is apparently the correct fill port and also like nomar said, it's possible to get to if the stock air box is in place. IF there was an aftermarket intake in place and the upper bolt was easily accessible, we probably would have just dropped a long funnel in.
 
If you're creative, you can grab some clear vinyl tubing from Home Depot and fill from the top with a funnel. You're done once fluid starts dripping out the fill hole. It's really easy.


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Nomar06 said:
It would have taken a lot longer to remove the stock air box to complete the entire job.
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Nix said:
The side is apparently the correct fill port and also like nomar said, it's possible to get to if the stock air box is in place. IF there was an aftermarket intake in place and the upper bolt was easily accessible, we probably would have just dropped a long funnel in.
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stilletto said:
If you're creative, you can grab some clear vinyl tubing from Home Depot and fill from the top with a funnel. You're done once fluid starts dripping out the fill hole. It's really easy.

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Thanks for the feedback everyone.
I'm really just trying to figure out why people don't use the upper bolt and a long funnel to fill the transmission with fresh fluid until it starts to drip out of the side bolt.
Other than the extra work of having to remove the stock air box it seems like it would be a little easier and you wouldn't need any special fill tools.
I've never replaced transmission fluid myself so I'm weighing out the pros and cons of doing it each way.
 
On top of the time savings you have to crack open the side fill port since that's how you measure if the trans if filled up to the correct amount.

Since your down there, it just makes sense to fill from there if you have the cheap pump thing that Nix mentioned.


In the time it takes to take out the stock air box out to get enough clearance to go that route, you can do the entire job by going through the bottom of the car.
 
Nomar06 said:
On top of the time savings you have to crack open the side fill port since that's how you measure if the trans if filled up to the correct amount.

Since your down there, it just makes sense to fill from there if you have the cheap pump thing that Nix mentioned.


In the time it takes to take out the stock air box out to get enough clearance to go that route, you can do the entire job by going through the bottom of the car.
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I'm actually starting to think that's the quicker way to do it especially after reading @stilletto's post (not to say your idea isn't a good one as well @Nomar06)
You're right about might as well fill it through the side bolt seeing as you have to take it off anyway.
 
To each his own, I guess. The time savings discussed is moot in my mind because in the "additional time" required to remove the air box, you have to raise the back end to level and spend the time pumping away to fill the two separate bottles with using the side fill port. It literally took me 5 minutes to remove 1 hose clamp, 1 connector and one screw to pull the box out and put it back in. I just filled it based on what came out which also concurs with what is listed in the specs. 2 full quarts came out, 2 full quarts went back in and full access to the top of the transmission vs an access hole via the bottom the size of a fist. Either way, you get the same result - fluid changed.
 
Yeah, fenders were getting rolled after the fluid change so the car was already up on stands and level.
 
Plus my car being lowered.....you have to put it up on 4 jack stands no matter which method you use.
 
I think almost every DIY I've ever watched in youtube for whatever make/model of car did their change with a hose/pump.

They'd break the top hole open
break the lower to drain
close the lower hole
fill into the top hole with a pump till it overflowed out
close top hole
 
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