Molybdenum Disulfide as a Lubricant Addative

I doubt that one could tell any difference after adding MoS2 to either.

I'd check the owners manual or ask a dealer before I put ANY additives in either one. They are very expensive to replace. I know that some differentials require very specific lubricants.

Generally, if there really was an additive that could improve the engine or transmission operation, the oil companies would have already put it in their blend.

MoS2 is extremely effective as a friction (and wear) reducing agent when added in lubricants specially on extreme pressure and shock nature loads, but it is also associated with environmental and health hazards. Anyway I don't think you will notice significant rolling ease difference in normal to low stress conditions comparing to a good lubricant or have worth mentioning fuel efficiency improvements in other than racing. S.M.

If you want to try it, (but usually not a good idea second guessing the car / oil makers etc) the easiest way would be to make a trip of say 100 km before & measure the diff temp rise, then add the MOS & retest temp rise, under similar conditions.

Works great but do not use on any type of limited slip differential that uses clutches. All others work fine such as Detroit Locker etc. Do not use in Automatic Transmission.

Many years ago I had an MG TA sports car. This had an oil-bath clutch system. "Molyslip" was heavily advertised at the time, so I put some in my engine oil. After 2 days, I could put the car in gear, let out the clutch and the car would not budge at all. I could get out of the car with engine running at tickover and in gear. 100% clutch slip. So does MoS2 work? Too damned well! Molyslip sent me 2 gallons of flushing oil, but that didn't work. In the end it was a new clutch and they were good enough to pay for most of it. My complaint was that there was no mention of "do not use in oil-bath clutches" on the can.