I was surprised to learn from a seal handbook that the temperature
operating range of most seal materials is seriously derated when
used with gear [presumably sulphur] oil. The temperature limit seemed
to be the same as the operating conditions. On hard used vehicles
we've found seals to often leak, and always loose lip shape. Removing
pressure buildup will make the marginal seal much more effective.
Regular replacement is necessary. And see what better modern seals
might be available. Most of the aftermarket suppliers, bless their
hearts, are under more price pressure than quality concerns.
--Carter
|