Not trying to be smart,but they recommend using the additive with any sure-grip.I,d add it for piece of mind.My 1.978 cents.:-D
I think this is because dino oil doesnt have friction modifiers though.
http://www.smokinvette.com/corvette/articles/a-study-of-automotive-gear-lubes-part-1/ this is a pretty thorough test of the top gear lubes and the following paragraph states they have the nessasary additives for sure grips. Review Candidates
The cross-section of gear lubricants tested includes those offered by original equipment manufacturers (OEMs), motor oil companies and specialty companies. All gear lubes, with the exception of Mopar Synthetic and Torco SGO Synthetic, are recommended by their manufacturers for limited-slip differentials and are therefore expected to contain appropriate limitedslip- type additives. Mopar limited-slip additive was added to Mopar Synthetic and Torco Type G limited-slip additive was added to Torco SGO Synthetic at the recommended levels to ensure equal testing. Each gear lube tested is listed in the following chart along with the performance specifications identified on the respective bottles. Batch codes are also listed.
Gear lubricant specifications are established for minimum performance levels. The active API gear lubricant specifications are API GL-4, GL-5 and MT-1. API GL-4 designates the type of service characteristics of spiral bevel and hypoid gears in automotive axles operated under moderate speeds and loads. These gear lubes may be used in select manual transmissions and transaxles. API MT-1 designates lubricants for non-synchromesh manual transmissions and transaxles. API MT- 1 is independent of API GL-5. API MT-1 calls for a higher level of oxidation stability, copper corrosion resistance and seal compatibility, which is not provided by API GL-4 or GL-5. Not all gear lubes meet API MT-1 performance standards.
API GL-1, GL-2, GL-3 and GL-6 are inactive. API GL-6 is identified by Lucas, Red Line and Torco as a performance specification. However, the test equipment is obsolete.
The U.S. military has established separate gear lube specifications. The most current military specification is MIL-PRF- 2105E, which supersedes the previous specification, MIL-L-2105D. MIL-PRF-2105E combines the performance requirements of MIL-L-2105D, API GL-5 and all but one parameter of API MT-1, thereby adding improved oxidation stability, copper corrosion resistance and seal compatibility to extreme-pressure axle lubricants. An additional gear lube standard, SAE J2360, mirrors MIL-PRF-2105E and is a global standard used by oil companies in countries where U.S. military standards are not applicab What I understand this to mean is that of all tested hereonly mopar synthetic and torco dont have the additives