Allison 5sp: SC4 Odd venting problem

[Mike_S]

I have a suncoast stage 4 transmission, with an odd issue. When the outside ambient temperature drops to about 15 degrees or below it spits ATF out of the vent on the top of the case. It won't do it all summer long, only in the winter, and only when it gets below that temp. Soon as the trans is up to temperature it quits. Doesn't seem to matter if the truck is in gear or not, or in motion or not.

Anyone got any suggestions on what could be causing this? Or how about suggestions on how to remedy the situation? Perhaps I'll just have to get a pan heater and plug it in with my block heater at night...

Mike

 

[Mike L.]

Drill 2, 1/8 inch holes in the fillertube about 4 inches below the top. The trans breathes through the overflow breather on top of the case and the filler tube. Sometimes the dipstick seals the top of the tube too well and fluid needs to expand through the overflow. This should fix it.

 

[Mike_S]

Oh awesome simple fix! Thanks Mike! :thumb: