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View Full Version : Possible tranny fluid level discrepancy in the factory manual


TouringBubble
08-23-2010, 02:09 PM
So, people on EvoM have said for a long time that one of the problems with the 6-speed is that it doesn't hold as much fluid as the 5-speed. I always wondered why that was said ... was it just an assumption that turned in to forum "fact?" Well, come to find out, it's in the manual.

But, I've always looked up my fluid capacities online with AMSOIL and they state that the 6-speed actually has more fluid. They have the capacities listed reversed from the factory manual. So, I'm looking in to the discrepancy.

This is the conversation as it goes currently ...

-Next, since there is more gears crammed into basically the same area, the 6speed has less fluid capacity.

I've seen this mentioned more than once, but I'm not sure why. The fluid capacity is actually higher in the 6-speed. I'm kind of wondering where this piece of info keeps coming from.

Now, this isn't to say that the extra capacity means each gear has the same amount of fluid volume as the 5-speed ... but here is a little basic math to quantify ...

2006 model year capacities
5-speed fill - 4.7 pints/2.35 quarts - .94 pints:1 gear
6-speed fill - 6 pints/3 quarts - 1 pint:gear

I've stated for a while that I feel improper cooling is the main factor of 6-speed failures. This, in my opinion, has a lot to do with removal of the factory undertray which provides cooling to the transmission and TC. But, as people have said, it does have a weaker 4-6 and most anything will fail eventually when pushed hard enough.

You got it backwards, the 6 speed holds less fluid. Look it up in the owners manual.

You're correct it seems ... which is weird. The manual specifically states 3qt for the 5 speed and 2.3qt for the 6-speed.

I've always looked it up with AMSOIL and they do seem to have it backward ... well, one of them does. You'd think the OE would have it printed correctly, but also being printed it can't be updated if it is wrong, where AMSOIL could have made a correction ... I don't know. I'll look in to it with AMSOIL and see what they say.

I've always filled the tranny based on when the fluid tops off ... I've not measured it. I want to say it's taken just under 3 qts in those cases ... but I honestly don't know. I've only used capacities to make sure I had enough fluid. I do know that the 6-speed transmission case is larger than the 5-speed, which would back up a larger capacity, but it really all depends on the internals and the fill level ...

Kind of an odd discrepancy ...

UPDATE :: My AMSOIL guy said that AMSOIL gets their fluid capacity data from a 3rd party source, but he's checking with his contacts to make sure the data is correct. I'll post back when I get an answer.

Just checked with a second independent source on the fluid capacities ...

W5M51 (5-speed) - 2.2l (2.3qt)
W6MAA (6-speed) - 2.8l (2.9qt)

This is interesting ... 2 independent sources disagree with the factory manual. I'll wait to see what AMSOIL says about it ... but I'm leaning toward a possible misprint in the factory manual. I know we often think the OE doesn't think much when designing things, but running so much less fluid in the 6-speed would be a huge oversight in the design.

Chemwarrior
08-23-2010, 03:17 PM
I think it's odd that the manual would read wrong. Afterall they would be liable if somebody's transmission took a dump because of not enough fluid in it. That is if Mitsubishi covered their warranties.

TouringBubble
08-23-2010, 03:50 PM
That depends on if the fill procedure is listed correctly in the manual. If it is, they have no worries. Chance that, or mail out all new manuals to every Evo owner? Worth weighing ...

I mean, it's hard to believe that such an oversight could take place, but I personally have like 5 page updates for Katie's manual for the GTi sitting at the house now. They designed it as a 3-ring binder so it could be modified. This speaks to how often mistakes occur in manuals.

either way, I just want to know. Putting less fluid in a transmission with more moving parts makes 0 sense and I can't believe anyone would engineer such a ridiculous thing and let that get by QA.

shunderwunder
08-23-2010, 07:08 PM
I was always under the impression that the cases were the same size & that the 6 speed was a little weaker due to the gears being a little slimmer to allow room for an extra gear. I've never seen a 6 speed up close so I have no idea how they compare. I would say that Tre or Shepard would be the best to ask since I'm sure they've seen the ins & outs of both plenty of times.

TouringBubble
08-23-2010, 07:49 PM
Someone just posted up the FSM info for the '06. It matches the manual with the 5-speed holding more fluid. I've asked him to check the 2005 as well ... that should put it to rest. I don't think they'd make a typo in 3 different places.

Andy, the 6-speed case is a little bigger, but it's also got more crammed in there.