gearbox oil seal additives

[Gmg31]

I changed my gearbox oil seals last winter and it made on a 50% difference.  Has anyone tried any of the sealant additives on the market

[jbcollier]

Make sure the seal run has snapped in place over the o-ring.

[Pfreen]

I looked at additives for the transmission and engine to stop leaks. My drive shaft seals have always leaked, no matter how often I change the seals. It seems there are two types.  Lucas thickens the oil so it doesn't leak, or at least reduces the leak. The other additives swell the seals.  Neither approach seems attractive to me.  I guess the most important thing is that the transmission hold together, in my case, a 365 5 speed.