ULTRA 1PLUS SAE 75W-90 Synthetic Gear Oil, API GL-4

Great company, Great price, Very Hard to find a quality affordable GL4 synthetic oil anywhere else. Great service

Good price.

Hard to find in my little area and at a great price.

Price is good

Good gear oil

Great gear oil changed front and rear differential oil truck is running great and quieter.

20K mile and over a year later Update below after original review: I'm using this in a 2007 Mazdaspeed 6 transmission (manual AWD 2.3L turbo). It seems GL4 is getting harder to come by, my local auto parts store didn't have any in stock, only GL5. I ordered this to try it out. My transmission has brass synchros, and I've heard not to use GL5 in it since most cause accelerated wear to soft metals. Shifts are smooth even before the transmission is up to operating temp, But a little more notchy than before, but no grinding experienced yet and notchiness may just be because it's a High milage transmission @155K miles. The mazdaspeed 3&6 transmissions are a little picky with oils as far as feel goes, I don't know what fluid was in it before as I bought it with 150K miles on the odometer and wanted to make sure the fluids were changed out since unknown service history. But when I swapped the transmission fluid it looked pretty clean and new. But at least this way I know it's got the proper fluid in it. I'm happy with it, and will try their GL5 synthetic for my transfer case and rear differential next, as I just bought conventional Lucas to swap for now from the auto parts store. Will update review if the fluid starts to break down quickly or causes issues.20K mile update as of 8-23-23: transmission still feels just as good as when I changed to this fluid, no breakdown of the GL4 has occured that I can fell. I will be changing it out again at 30K miles, or when I swap in my built motor, whichever is first. Will definitely purchase this again. The notchiness I spoke about seemes to have lessened some as well, or I don't notice it anymore. Transmission still shifts well and goes into gears with no hassle. It's a safe buy for mazdaspeed 3's and 6's for sure. And I'm sure it will work great in any other transmissions that require GL4 of this weight.

Figured out it wasn't too hard to do a gear oil change for my smart fortwo 451 from online video guides. So I purchased this and give it a try.Heard it takes 2.3 quarts so I bought quarts of 3. Unscrew both fill and drain plug at the bottom. With so much clearance I don't have to jack the vehicle up.My car has ~60000miles so I'm not surprised to see the old oil is dark and grey. I use the tube from a pump set and pipe thru it around the engine. Put a funnel at the end and pour the new gear oil in it, very slowly.After pouring two bottles of it, I have to slow down not to over pouring it. As soon as I pour the 3rd one close to the 0.5L mark from the Ultra1Plus oil bottle, it overfill and immediately stop filling it.Re-screw the fill plug and call it for the day.Drove the car on the next day, and the difference is noticeable. Shifting from 1to2 and 2to3 are no longer jerking or sudden speed stop anymore. Shifting is now way smoother than before on every gear. Accelerations are much better too. I can feel its power is much faster and vival than before the oil change.I'd highly recommended for cars that needs transmission/gear oil change that specifically takes GL-4.