transmission vent?

gtlaw

Member
:
ms3
with 400 miles on the odo I decided to switch the gear lube to redline mt-90. I took the car for a short drive, and when I unscrewed the fill plug it hissed. I couldn't tell if it was pulling vacuum or relieving built up pressure, but I thought it was odd. shouldn't there be a vent on the top side of the trans? I'm thinking mine is stuck closed if there is one.
 
BTW the trans was still filled, and the drain plug wasn't removed yet. I know it would do that if it was draining at the time I removed the fill plug
 
when i switched to mt90 mine made that noise too, at first i thought it was my friend under the car with me dicking around making noises with his mouth..but i think its just the air pressure or somethin. I havent had any problems since..
 
come on there is more than 5 people on this board maybe I should have put SRI or CAI in the title
 
come on there is more than 5 people on this board maybe I should have put SRI or CAI in the title

thats funny as hell!!

when i changed mine, i too looked for a vent and there was none. However, i did not get any hissing sound when i removed my tranny plug.
 
the tranny was built at a differant altitude than what you are at.. so it seems like its a sealed unit.. bam.. pressure release..
 
there is definitely a vent on top of the transmission. It is a little brass looking dome thing with a few holes on the side...
 
There is a certain level of pressure it requires though as they don't want a free exchange of air in there as it could cause corrosion. But when heat builds up it does let out some air so it doesn't blow out the seals at the axles.
 

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