Original post by: blackwood ,
Lucus only boost the weight of the oil so if you have 15/40w and add Lucus it boosts it to 15/50w. You might look at Motorkote, it's a friction fighter. I have used it for several years in everything I have. I can only tell you that I have a Yukon that I melted the planetary gears twice in three years. I was told that this is a common failure in Yukon /Tahoe and trucks that run 4L60E transmissions. After paying for this repair twice I added the amount advised to the transmission fluid and have run and towed with this vehicle for the last 6 years without any trouble from the transmission. Call Motorkote or go to their website and read the testimonials.....