Transmission leak fix

Apr 7, 2011
39
1989 catalina 27 Pearson 1987 milford
Hi,
I recently installed a used ZF10M (Hurth HBW100) with low hours (250). It works great but leaks about 1 oz per 10 engine hrs (with a design quantity of 12 oz). I've been using ATF per manual, but may switch to 30 Weight engine oil.
It was suggested that I try a xmsn stop leak product. Has anyone had good results or heard of a good product?
Initial checks suggest that the rear seal is the leak source.

Thanks,
Chris
 
Sep 25, 2008
7,446
Alden 50 Sarasota, Florida
Such products can minimize or eliminate oil seal leaks but if your leak is at the gasket, it likely won't work. I'm unfamiliar with your tranny so can't say for sure which problem you have.
 
Feb 26, 2004
23,049
Catalina 34 224 Maple Bay, BC, Canada
Don't use oil in that transmission. Continue to use ATF. Why? 'Cuz that's what Hurth recommended and has for decades.

Where is it leaking from? If it is the drain hole at the bottom, try getting a new crush washer, they're one time things.

Good luck.

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