My 2003 Jaguar XJR was a South Florida car all its life (warm Climate). It is now in the Atlanta area where it has sprung oil leaks through the the valve cover gaskets that were replaced six months ago and a small transmission leak. Is there a product I can add to the motor oil and transmission to eliminate these small leaks? I figure I have nothing to lose before having to spend hundreds dropping the tranny and removing essentially new valve cover gaskets. Do you think the valve cover gaskets may need re-torquing do to the extreme climate change? Where is the filler tube for the transmission? Does anyone have a pic?

Thanks in advance.

 

The valve cover gaskets are thick and can be reused, so take them off and see if the heads and covers were cleaned before the new gaskets were installed. The o ring type seals for the cover screws might not have been replaced if the mechanic was lazy. The cover fasteners should be torqued to 9 Nm, about 80 lb/in. If they are overtightened the valve cover could crack.
It gets very hot here in the summer, and we do not have oil leaks due to the climate. I would not use oil additives in an attempt to reduce leaks. I tried some Lucas stop leak for a rear main seal, and while it made a difference, that might have been due to the high viscosity as much as swelling the seal, so I only used it for about 500 mi.
Some one else will have to help with the transmission dipstick question.