Transmission Oils

["Jerry Barr" <jerrybarr@charter.net>]

Hello Group,
 
I am installing a new transmission with a J type overdrive in my GT6 and
am STILL confused about what type of lubricant to use in the
transmission/overdrive unit. My Standard Triumph factory manual said I
should use 80w-90 GL4 gear lube but I have heard lots of different
recommendations. I use 40w oil in my TR3 and 20w- 50 in the non
overdrive transmission now in the GT6 with good success. Does this
esteemed group have any recommendations?
 
Regards,
 
Jerry Barr