My favorite old, semi-retired tranny guy turned me on to this new seal. I am going to try it this time around as I often have a leak there even with a new stock type seal. He also showed me another stock style seal that was taller than the original ones to get away from a possible groove in the shaft. That one is only a couple of bucks. The new style in the pic is over $10. Worth it IF it actually stops the leak.




He also mentioned that he can get a brass bushing to go in the case to tighten up the dip stick tube O ring which is another place I often have a leak. That bushing will be in next week. Apparently, it just taps in place. When I get it, I will post pics of it and it's package for those that might be interested.

Dipstick tube o ring…. That prob was solved with the newer dipstick’s with the larger push in style seal. Even way back in the early 90s we brazed on a chev dipstick tube end on ours to take advantage of their seal that didn’t leak.

I've never had either part leak when properly cleaned and lube during install. Bet I've built close to 30 of them in the last year or so.
Doug

I've always thought that it's the grit that accumulates around the shaft that eventually leads to seal failure.

My tranny guy says it's the converter drain back that puts the pressure on the seal causing it to leak. He sees it all the time. Good pump seals with no grooves in the housing and a converter drain back preventer is the best preventative course according to him. I do have converter drain back and didn't want to tear into an otherwise very good operating 518. So, I will try this seal.

The pressure is your base atmospheric pressure on that seal when the fluid finds it's level with the trans off.

This and JK. The dirt buildup damages the seal and shaft which allows it to leak even with no pressure on it.

As for the dipstick tube, make sure the end is round and inserted straight. If you have to bend or shim the support bracket do so.

Don't forget the seal on the TV shaft too.