Slightly overfilling Manual Transmission

Posted by: daemontrym

Slightly overfilling Manual Transmission - 12/27/13 11:27 AM

I have a 2012 Kia Forte 6spd with 38k on it now. The owners manual says the transmission holds 2 quarts of fluid. But, on Kiatechinfo.com I am able to access the actual service manual the dealership uses to repair the car. On kiatechinfo.com it says to fill the transmission until it starts weeping out of the fill hole. After putting in 2 quarts I don't feel any weeping or cannot feel the fluid below the fill hole. So I put in a little more than a half quart and still don't really find any weeping. I don't really want to put in anymore because I would be over a quart over what the owners manual says.

So far its 2 quarts of Amsoil MTG and about alittle less than 2/3 of a quart of Pennzoil Synchromesh 75w90. The trans shifts the best it ever has with this mix, I just don't want to mess up my trans.
Posted by: rationull

Re: Slightly overfilling Manual Transmission - 12/27/13 12:19 PM

Is the car level?

I'd have no qualms about filling it until it starts seeping out, provided the car is level while filling. I typically use the spec'd capacities only as a guide and rely on whatever "measurement device" is included on the car for the final say.
Posted by: Blaze

Re: Slightly overfilling Manual Transmission - 12/27/13 12:20 PM

I recently found out my John Deere manual was off by 2.5 qts on the front differential. I called the dealer and the service tech gave me the right amount so manuals can and do misprint. Can you put your pinky in there? If I get fluid up to my first knuckle I figure I'm good to go.
Posted by: JHZR2

Re: Slightly overfilling Manual Transmission - 12/27/13 01:03 PM

Originally Posted By: rationull
Is the car level?

I'd have no qualms about filling it until it starts seeping out, provided the car is level while filling. I typically use the spec'd capacities only as a guide and rely on whatever "measurement device" is included on the car for the final say.


+1 to both statements here.

I have seen some diffs/MTs that you fill to a specific level below the fill hole, like 1/4", and youre supposed to feel in to identify the level. Forget what vehicles...

Id fill it until it comes out but if you put in a genuine 2 quarts, and all data indicates that this is the right amount, then Id be OK with it...
Posted by: daemontrym

Re: Slightly overfilling Manual Transmission - 12/27/13 01:57 PM

I changed the MTF on level ground inside of my garage. I am able to stick the tip of my pinky in the hole, but the threading prevents me from angling it down to feel fluid. I filled the trans just as much with MT85, first run of MTG, Castrol syntorq, and now my blend of Pennzoil synchromesh/ MTG. I have done this for 37k now and have not noticed any foaming, bubbles, or overflow coming out of the trans vent.

With the 2quarts of MTG and maybe a little less than 2/3 of a quart of Pennzoil Synchromesh
is the best thing to ever happen to this car. I just don't want to detract from longevity with my frankenbrew.
Posted by: GutsyGecko

Re: Slightly overfilling Manual Transmission - 12/27/13 02:20 PM

I would add the last of the 3rd quart and forget about it.
Posted by: antiqueshell

Re: Slightly overfilling Manual Transmission - 12/27/13 03:47 PM

The typical method of filling a manual transaxle is to fill to the point where a small amount of oil comes dripping out of that hole.

I'd fill till it drips a tiny bit and not worry about it.

In any case it is better to have a bit too much in a manual trans than too little.
Posted by: INDYMAC

Re: Slightly overfilling Manual Transmission - 12/27/13 04:15 PM

Have you talked to a Kia service department to see how they are handling this situation? Is there a service bulletin about it? There has to be a tech that has asked the question by now.
Posted by: y_p_w

Re: Slightly overfilling Manual Transmission - 12/27/13 10:10 PM

Depends on the car. With a Honda MT, you fill until the fluid (was motor oil at one time) comes spilling out of the horizontally mounted fill hole. I don't think anything bad could really happen if you manage to overfill that kind of tranny other than having to clean up the excess fluid. Even if you manage to fill it an close the bolt before it had a chance to drip out until it's perfectly level, that shouldn't do any damage.

Other transmissions might not be positively sealed like a two bolt MT. My WRX has a dipstick, where the dipstick tube also doubles as the fill hole. I could imagine filling that until it comes out the dipstick tube, but that would take a lot of fluid.
Posted by: badtlc

Re: Slightly overfilling Manual Transmission - 12/27/13 10:23 PM

If you have two holes including a horizontal fill hole then there is a reason you don't have a dipstick. You fill until it comes out. There is no other way to know 100% that you hit the full mark.

My Mazda OM said my MTX took 1.7 qts and it actually takes 2.4 qts. It was a misprint.
Posted by: daemontrym

Re: Slightly overfilling Manual Transmission - 12/28/13 09:50 AM

Before I changed the MTF at 8k the first time I questioned them about a couple of things. The first thing was how notchy it felt and they said it will loosen up with time. The second issue whats that from 65-75 the shifter would visibly start shaking. Then when you would slow down or speed up it would go away, the tech said its a normal harmonics thing.

All of the MTFs I tried got rid of the shifter starting to shake, but the notchy trans it took some experimenting.

I have been driving manual transmission cars and trucks since I started driving since I prefer them. But, this car took a real long time to get used to its quirky trans.


The main problem is the clutch has no feel until it engages and disengages, but when it does grab its very aggressive so you really have to finesse the pedal starting and shifting. Plus the car has drive by wire that is pretty badly tuned with a delay before it starts revving. Then after that its very hard to modulate because they have the first have tuned very aggressive so its like an on off switch rather than a gas pedal.

Once I put in the Amsoil/Pennzoil synchromesh mix shifting and general operation is a lot better. I cannot fix the clutch or gas pedal problems, but now its not annoying to drive it during an 80 mile commute every day.
Posted by: sciphi

Re: Slightly overfilling Manual Transmission - 12/29/13 08:31 AM

No harm to slightly overfill a manual transmission. If anything, it's more oil to help dissipate heat better.

Amsoil Synchromesh did wonders for my Cruze's 6-speed transmission. Give it a few shifts and it loosens right up even when stone-cold.

It never ceases to amaze me what junk fluids the OEM's put into their manual cars, at least the cheaper ones.
Posted by: Ducman

Re: Slightly overfilling Manual Transmission - 12/30/13 07:23 PM

Don't worry too much about it. The old rule goes like this "what it doesn't need, it will either spit it out or burn it".
It's a somewhat oversimplification I know, but I think you get the drift. But you won't be burning it in this case.

It's standard practice to fill up to the bottom threads of the filler hole on most transmissions, transaxles and diffs.
In all practicality it's quite hard to "actually overfill" a transmission unless you're trying hard to do so.
Unless otherwise specified by the manufacturer, you should be able to safely fill to the bottom of the filler hole.
The only major exception of course, is Automatic Transmissions.

The only other exception is with the T56 in my car which normally takes 4 litres of Dexron III spec ATF.
This exact same transmission is fitted to many different makes and models of vehicle with a nominal fill capacity of 4 litres across the board.
For all T56 transmissions fitted by GM in all their later models, the manufacturer has issued a TSB stating to over fill by 10% thus taking the total ATF to a nominal 4.4 litres. Which is well over the filler hole in the side of the transmission.
The only way to get the extra 400 ml into it is through the speedo sender unit hole.
As described in the TSB.
They still don't leak with the extra oil in them.

In summary use your common sense and don't panic.
As previously mentioned, make sure the vehicle is level.
Posted by: y_p_w

Re: Slightly overfilling Manual Transmission - 12/31/13 03:50 PM

Originally Posted By: Ducman
Don't worry too much about it. The old rule goes like this "what it doesn't need, it will either spit it out or burn it".
It's a somewhat oversimplification I know, but I think you get the drift. But you won't be burning it in this case.

A manual transmission with horizontally mounted fill and drain bolts should be completely sealed once both bolts are closed. If you could inject fluid in the fill bolt, close it up before too much spills out, and drive it off - there should be no issues.

Another issue would be thermal expansion. If you fill it cold until it spills out and check it warm, there will likely be some spilling out of the fill hole. It wouldn't be enough to be an issue.
Posted by: daemontrym

Re: Slightly overfilling Manual Transmission - 01/01/14 02:18 PM

I wasn't super worried since everything feels much nicer, but just was looking for peace of mind. I am thinking of running this mixture out to 60k or until it starts getting severely notchy. I think its perfectly doable since the owners manual says MTF is life time fill or 80k oci if severe service. Seems like a long OCI, but I typically put 30k a year on my car because I have an 80mile round trip daily commute.

Next OCI I am going to try an amsoil MTF/MTG 50/50 mix since my trans calls for 75w85. With MTG by itself the trans is notchy until it warms up, but with the 2/3 qt synchromesh in there it shifts like butter.
Posted by: Ross

Re: Slightly overfilling Manual Transmission - 01/02/14 12:36 AM

This very same thing happened to me with my 2011 hyundai accent. The manual said 2 quarts. I kept adding and adding until I had almost 3 quarts in. Truned out I had removed the wrong bolt to drain the fluid. I was using a bolt much higher up. I found the the correct bolt removed it and let it drain. About 1 quart came out and all is well. I am using redline MT 85 and I like it thus far.
Posted by: Unsullied_Spy

Re: Slightly overfilling Manual Transmission - 01/03/14 10:07 PM

Generally speaking the fill hole is located where the fluid level needs to be. Sometimes there is a TSB regarding fluid levels (check with your dealer's service department) but usually just fill until it starts dribbling out and then re-install the plug.

Again, check with your service department. My 2002 Mustang GT with a Tremec TR-3650 was spec'ed to fill up to the hole, then they said only to put 3 liters in it because of shifting problems.
Posted by: MolaKule

Re: Slightly overfilling Manual Transmission - 01/03/14 10:46 PM

Quote:
daemontrym: ...and 2/3 of a quart of Pennzoil Synchromesh 75w90


Where did you find a 75W90 Pennzoil Sychromesh?
Posted by: daemontrym

Re: Slightly overfilling Manual Transmission - 01/04/14 09:25 AM

Molakule I didn't find synchromesh 75w90 its a typo..

I am going to look in Kia tech info online and make sure I have the right bolt. Kiatechinfo.com gives you access to the actual kia repair manual the dealerships use.