bonnie john said:can someone please tell me the EFFECTIVE difference between running a GL 4 and a GL 5 oil in the box of my 92 'boy. also like to know WHAT is a GL4/GL5 rated lubricant?
A GL4/GL5 lubricant covers all the bases so to speak and the only time you need a specific GL4 lube is if the manufacture determines that a GL4/GL5 would be detrimental to it's gearbox chemical wise (potential destruction of the yellow metals and copper etc.). Typical machinery that require GL4 lubes are stern drives, lower units on outboards, and manual shift transaxles in cars and trucks. As far as operational wise you will see no difference in shifting or wear in your tranny since a motor oil can even be used in your bike according to harley. Motor oils and GL4 only rated gearlubes use anti-wear agents as a general rule in their chemistry, but there is some advanced formulations that actually use extreme pressure additives in their GL4 fluids that cause no damage to gear boxes that call for a GL4 only fluid. Amsoil has such a fluid. It is usually hard to find GL4 only fluids in the market place, as most gearboxes that call for a gearlube spec out the GL4/GL5 fluids. Hope this helps.bonnie john said:can someone please tell me the EFFECTIVE difference between running a GL 4 and a GL 5 oil in the box of my 92 'boy. also like to know WHAT is a GL4/GL5 rated lubricant?
You are correct about it being temperature related, but I don't have the exact temp handy. It is a continous temp a little over 200 degrees I think. If you have to know exactly I can do some research.bonnie john said:that is a huge help thankyou george. to continue, if i am to understand the yellow peril, it is only re-active if the oil reaches a certain temperature and THEN starts to decompose the brass/bronze/ copper in the transmission. i would like to learn a little more about the temp etc please
70 bonnie like in Triumph?bonnie john said:that's fantastic george, but all the boxes i have touched have never been as hot as the engine, not even too hot to touch, so maybe it's academic. i will now be happy putting anything in my 70 bonnie which has yellow thrust washers and a bronze high gear/ mainshaft bearing.thankyou for all your interest and help
I had 2 British bikes in the late Sixties. A 1964 441 victor special single cylinder and a 1966 BSA 650cc thunderbolt I think it was called. My memory is getting bad going back that far. They were fun in their time.bonnie john said:yes, bought it in NZ in 1979, rode it and rebuilt it with hyde parts, all unserviceable at 800 miles, retired it and rode a triumph hurricane till 2000, bought an flstf new in beginning of '92, STILL SMILING ...