Lucas Oil10121 SAE 75W-140 Synthetic Gear Oil/Transmission and Differential Lube - 1 Quart

I needed to do a fluid change on the rear diff of my 2002 F150 with factory limited slip.I have never used any Lucas product before, only seen their oil additives (and I don't use additives at all, Lucas or other brands).I have read some bad reviews of Lucas gear oils, but most seem to be complaining of issues in transmissions or transfer cases, not differentials, so I figured why not try it. It meets all the specs and is cheaper than other synthetic fluids of the same viscosity (even cheaper than Supertech 75w-140 synthetic from Walmart). I did notice this fluid does not have as strong a foul odor like some gear oils do. It still smelled, but not as bad as others I have used before.I changed the fluid with no major issues and it seems to work just fine. I did add the Motorcraft XL-3 Friction Modifier to the differential. The Lucas fluid is supposed to contain Friction Modifier and it says no need to add more, but I have heard of many people having rear end chatter with the OEM Ford LS no matter what fluid is used unless the Ford friction modifier is added too, so I did it.I was having some chattering from the rear end when doing sharp turns from a stop before I changed the fluid, no issues at all after the change.I only gave it 4 stars for now since I don't know long term how this fluid holds up. If it is still good in a year, I will change it to 5 stars. As of right now, I would not hesitate to use it again.Edit 7/10/15: Well, it is a year later and nothing to report except truck is still running fine with no noise or leaks from the rear end. Seems like a solid choice for gear oil for me. Will be on the top of my list if I need more. 5 star rating now.another edit 9/16/16: well, no more updates on this fluid. I had to drain my rear diff (had to replace the anchor plate for the passenger side brake caliper, which requires removing the axle shaft and draining the fluid). I debated re-using the fluid, but decided not too. The fluid came out looking almost like it went in. Only had 10,000 miles or so on it though. I did not use more Lucas fluid for the refill, I just went with some Supertech gear oil from Walmart instead. Seems the price of the Lucas has gone up and cost as much as other name brand fluids, loosing its biggest advantage for me (low cost).

Only oil I use for differentials. Have recently changed the oil in my ‘11 Dodge Nitro, ‘05 Chevrolet Astro and ‘91 Camaro. Bottle is easy to use with minimal spillage.

Never go to a dealership to buy this type of product. The double mark-up on price is sad.This is better than original, and was used in a Posi diff.

Geat product, can’t go wrong with Lucas. Came packaged very well. With all the prices going up on everything this is a steal for the value!

the product was fine the delivery was early no notification package was out in the rain for a day and a half

Works just as good as redline at half the cost. People that own older and newer Harley's know the transmissions are clunky and can be a pain to find neutral. It smooths out the shifts and helps the neutral hunting. 3 of my gear boxes are all above 65k and shift like new. I've always used gear lube and not the watery hd 3/syn whatever it's called these days. I also use 80-90 in the primaries. Never had a "slip issue " as everyone claims happens when you used gear oil. All original clutch plates too. With all the inner primary bearings going all of mine are still original.Those that know , know.

Better than advertised

good quality. good oil. my vehicle likes it.