682 Cast iron leak at rear transmission cover?
 

I just changed the hydraulic fluid in the transmission, but there is a leak at the new gasket. It leaked previously before the fluid change but there was no gasket, only RTV sealant. I'm thinking there is a crack in the case, or the cast iron is very porous. The leak was worse with the new gasket.

It appears to leak from this location (green arrow in picture below) which is just beside the bottom middle bolt hole.

https://live.staticflickr.com/65535/...3fdacaa5_b.jpg

I'm hoping to use J-B Weld SteelStik to cover that area on the inside of the case. Does anybody know what that brown coating on the cast iron is?

The internal coating that IH used is called "Glyptal".

Thanks! I'll try and find some.

Apparently, in my part of Canada, Glyptal is not available due to to some regulation, meaning we are not smart enough to handle this product. Nanny statism strikes again!

But an equal product, probably just as dangerous can be had. It's called MG-4228. I brushed a small amount of this onto the affected area that was porous. After about 10 hours of use, it still hasn't leaked, so all good now!

[IMG]https://live.staticflickr.com/65535/...32ab592c88.jpgMG 4228 by John deVos, on Flickr[/IMG]

Well I am glad you got the leak stopped. Amazing the gasket wouldn't
make up for that spot. Did you just put the gasket back on or gasket with
sealer? What else did you do? Just curios.

Ken

When it was leaking before any attempt at repair, there was only RTV sealer on the cover plate, no gasket. My first repair was to install a new gasket dry but it leaked badly. The final repair included sealing the porous casting further from the joint, and replacing the now slightly used gasket with RTV added to both gasket faces.