GL-5 One more time

[Utah Willie]

I recently posted this query but received no reply... . surely, there is someone out there who can tell me if there is any difference between an API GL-5 lube sold for truck differentials and an API GL-5 sold as marine outdrive or outboard lower unit gear lube? I know it seems obvious, but you'd never believe the answers I have received from parts houses, mechanics and retailers.

 

[radixr]

I think the marine GL-5 has more additives but is ok for the diff. Don't put it in your manual transmission!!!

 

[Utah Willie]

GL-5 is GL-5

After asking in several places, including here at TDR, I finally went to the "horse" and got the answer from the horse's mouth... so to speak. I wrote to API (American Petroleum Institute). API GL-5, whether sold as an automotive gear lube (quarts and 5 gallon pails) or as a marine lube for outdrive and outboard lower units..... is the same stuff. Since API GL-5 is a performance spec. , it is applicable wherever GL-5 lubricants are called for. The reason I was concerned about this is that I can find the marine package at Wal-Mart a buck and change cheaper than the auto package and they have a lot of it whereas most auto parts stores have just a few quarts, if that. The next question is whether Pennzoil synthetic comes up to par with other synthetics? I am using 75W-90. Esta bueno?