I recently put a TH350 in my K5 in place of the 700R4. I used a pre 1980 case and put in a newer GM dipstick that is water proof. DOOOH, the pre 80 4x4 cases are vented through the dipstick tube, after filling my t-case halfway up with tranney fluid, I finally figured it out. When things get hot and expand the pressure has to go somewhere, in this case it was the input seal in the t-case that was the path of least resistance. To solve the problem I drilled and tapped the dipstick tube and put in a small hose fitting and a hose that runs into the cab for venting. Now it's water tight and no more tranny fluid in the t-case. Just wanted to share in case any body else gets the water proof bug. <font color=red> Elkboy </font color=red> 82 K5 fuel injected H.O.305, TH350/205, 14bolt/10bolt and 39.5 TSL's.