Royal Purple 01300 Max Gear 75W-90 High Performance Synthetic Automotive Gear Oil , 1 Quart (32 Ounces)

Great product, I also use their motor oil for regular everyday driving. No racing at all and it had worked great for me. I just tried this gear oil and ai can already feel the difference. No complains this car. I just put it in last night and drove it today 06/27/25 and it feels good.

Basically the only gear lube I ever use. Great for transfer cases and sub trans applications. Quiet down them gears and provides excellent lubrication to keep them from wearing. You can't go wrong with this product. This is not a motor oil or a transmission oil. This is for differentials and transfer cases also known as a sub trans on some utv's.

Purchased for the front and rear diff in my Durango SRT. I had a "clunking/jerking" feeling if you would accelerate hard and after reading many reviews, the diff fluid needed to be changed. I was at 50k miles and was supposed to be done at 40 so I figured this would fix it. It sure did. It has the additive in it already and I will say putting this fluid in my Durango made it happy. It was a way better price then the Mopar brand of fluid and works just as well. I did purchase a pump to get the fluid into my rear diff. The front was easy to fill. Royal Purple has always been a great brand and still doesn't disappoint.

Fast shipping, super product

I was reluctant to change differential fluid on my Acura 3.5 RL due to its confined location but it turned out to be a great DIY experience thanks to Royal Purple. This oil totally caught me off guard as I was not expecting major improvement over the stock fluid but it really made a world of difference. Performance enhancement is very noticeable. My car more responsive and quieter, the entire power train is slicker thanks to lower friction, now I am kicking myself for not doing this sooner. Tip to DIY: Acura 3.5 RL's differential is in an awkward and confined position but it is actually very easy to change if you acquire the proper tools. First you need a 3/8 "flex head" long handle ratchet, standard ratchet/wrench/breaker bar will reach the drain bolt & filler bolt but you won't be able to turn where as a flex head allows you to "pivot" the handle so it can turn freely. The 3/8 drive tip removes the drain bolt & a 17 mm socket removes the filler bolt. After fluid is drained, attach a 1/2 inch clear hose about 25 inches long to a funnel, then snake the hose from top of engine block down to filler hole to refill. I have seen guys on Acura forums removing passenger front wheel doing this job which is totally unnecessary. Once you acquired proper tools the entire process takes no more than 30 minutes.

I used this stuff to replace the transfer case and differential oil in my 1999 Toyota Land Cruiser, which has a monster V8 engine and previously recorded a best fuel economy of 14 mpg highway. I checked fuel economy carefully over many trips on the highway, always driving conservatively at the speed limit, 65 mph in NY. So I'm very confident in the 14 mpg and that's best case driving. Town and stop-and-go driving was lower. Also the 14 mpg was measured after a recent engine oil and filter change with Mobil 1 Synthetic. Anyway, I'm pretty sure the transfer and diff oil was never changed by the previous owner, based on the condition of the drain screws and the fact that something resembling black pudding sludge dripped out during the draining process. The transfer case took about 4 quarts and the diff about 5 quarts. I "wasted" about one full quart during the oil change trying to flush out the gears by continuing to pump in more fluid during even after it started leaking from the upper fill hole. This did seem to cause a few squirts of additional sludge to come out through the drain. After the change I immediately noticed that the vehicle seemed a little quieter and smoother, it was a barely perceptible change but I'm pretty in tune with the noises this LC makes, and noticed a definite lower sound from the drive train, in fact it was very quiet overall. The big surprise was the gas economy, though. Halfway through the trip, which is about 100 miles and route I drive fairly regularly, I knew the gas mileage was better than before. Upon returning home and hitting the first gas station off the highway, I was amazed to find that my fuel economy went from 14 mpg to 17.42 mpg, an unbelievable 24% improvement. Nothing else changed with the vehicle, same driving style, same gas, etc. The only variable that changed was the use of Royal Purple. Assuming this continues, my fuel range is increased from approx. 280 mi/tank to about 348 mi/tank. This equates to a savings of roughly $15.50 per tank, or for city driving probably around $10/tank. So the whole load of oil will pay for itself fairly quickly. My cost per mile dropped from $0.30 to $0.23. I'm very impressed with this oil, so far it is one of the best things I have done for this vehicle. I will use it in my other car for sure. Expensive but definitely worth the price.

The gear oil is perfect as always, love Royal purple. The Plews pump included however, did not fit the neck of the quart bottle. The collar on the pump was to large and wouldn't screw down to the neck of the bottle. Thus the 4 star.

This 100% does replace Mazda SG1 gear oil and I'd immediately replace that mediocre junk (that can also be underfilled from the factory) in any Mazda transfer case and rear differential that calls for SG1. Per Mazda, the gear oil has to be GL4 safe, this is.. It needs to be for hypoid gears and contain the right additives, this does. Not many other ones meet this unusual combo and since it does it is legally warranty safe, the very slightly higher viscosity ("weight") rating than SG1 won't void your warranty either, if anything it will provide better protection at the expense of .01 MPG fuel economy. My Mazda 3 AWD turbo immediately took off with far less resistance and far less slowing down while coasting putting this in both gear boxes. *Literally* the best 14 bucks I've ever spent on a car, worth paying a shop to do for you if you have to!