Transmission fluid overflow

The past couple of days I've been checking around to figure out why my reverse lights werent working, and after replacing bulbs I decided to replace the reverse switch on my 5 speed. So I crawled underneath, and unbolted the switch only to get coated in a spray of fluid, which then continued to pour out of the whole. Naturally, I felt like an idiot because I thought it was my fault that I didnt research enough to figure out that this would happen. So I decided now would be a good time to replace my transmission fluid, I got 3 quarts of

$29 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 and started draining the old stuff. However, I drained nearly 7 quarts of fluid out of my transmission. The sources I looked at told me to pump in 2.3 quarts, with others saying up to 3. But that is far less than I got out. Anyone have any insight as to why so much was in there? Was it supposed to pour out of my reverse switch at all?

 

Wow, that's crazy. Actually that doesn't make any sense at all, lol. The manual transmission only holds enough fluid to reach the fill port, if you put in any more than that it will start to overflow out. I could see maybe squeezing in an extra half quart and plugging it real quick but there's no way you'd be able to fill it with 3 times the amount it's supposed to have. Something doesn't add up here.

 

Yeah, when I pulled out the reverse switch it poured out, also poured from the fill plug when I opened that, and then of course a bunch from the main drain. Im pretty lost here. I am unsure as to when the last time the fluid was changed, could it have thinned out this significantly?

 

I wonder if maybe whoever filled it last time thought that it was an auto trans? If I recall correctly, the auto trans holds way more fluid than the manuals do. Autos use ATF fluid though and not gear oil. Maybe someone mistook the auto fluid capacity for the manual when they serviced it, I dunno...that still wouldn't make sense how they managed to cram that much gear oil into it.

 

Has it been acting funny at all? With that much extra fluid I'd imagine it would be shifting funny at the very least.

At any rate, I assume it's got the right amount of fluid in it now correct? Hopefully the overfill didn't cause any long term damage, these manual transmissions are tough as nails.

 

I've never known any different, so I cant really say if it shifts poorly or weirdly. It has always been a bit notchy, but it still is after putting in new fluids. I pumped in a bit over 2qt, until it began to leak out, I believe that is the correct amount

 

Yup that's the correct amount. It's full when it reaches the fill port. And yes, the manual trans in Tacomas especially the first gens is notoriously notchy, mine is too. That's a really weird predicament you have there, I'm stumped lol.

 

At some time it seems someone filled it through the top by removing the shifter

How was the Transfer case level??

 

Ah that's right, I forgot that you could do it that way. I noticed mine was overfilled by about 1/2 a quart last time I had it done, when I asked on here about it someone mentioned that you could fill it from the top as well. But mine was done at a drive through Valvoline shop and they did it underneath, so I still don't know how they managed to cram an extra 1/2 quart in there lol. Must have used a machine that pumped it in fast and plugged it quick.

 

Transfer case level was normal..