Genuine Ford Fluid XL-3 Friction Modifier Additive - 4 oz.

I’ve tried other additives and oil with friction modifiers, but this is really the only thing that I’ve found that make trac-loc differentials with the way they should quietly. Doesn’t smell the best though.

I used this in my ‘03 Tundra limit slip differential as recommended on one of the Toyota forums. I used it when replacing the rear end gear oil. Seemed to work fine. It seemed to do what it is supposed to do for the limited slip to keep it working.

Cheaper than the dealer pricing

The transmission in my Ford van developed a shudder after 185,000 miles. I saw a video on YouTube showing someone tried this additive and it worked for him. So, I followed the instructions to pump out as much fluid as possible and replace with new fluid while adding this additive. Thankfully, I haven’t had another shutter in the hundreds of miles I’ve driven since.

I have a 2000 ford E350 ambulance with a 7.3 powerstroke diesel engine. 3 yrs ago I had to have the rear differential clutch pack replaced. I think he replaced the gears as well. He told me it will chatter a bit but would go away. It did chatter a bit but didn't go away. Recently it has gotten worse so I ordered 2x4oz. bottles of this stuff. It came in 2 separate boxes. I did order them alone due to other reviewers' warning about the smell and they weren't kidding. I also ordered a.big fluid syringe to "inject" it into the pumpkin. I have a prosthetic leg and some back issues due to a disc replacement surgery. This makes it hard for me to get under the truck so I took it to my friends shop. He had one of his young guys do the job for me. I won't lie, I also didn't want to touch the stuff. It stinks. Bad. The whole garage smelled of the stuff even still packed in the boxes. I put it in the side compartment of my van to bring it to the shop. I felt bad, the guy got it all over his hands and i.know it's going to be hard to get off. I hope he is allowed to sleep in the house tonight! Anyway by the time I got home the chatter seems to be.gone. I will have to do some serious sharp turns and reversing on an incline to know for sure, but it already is better doing normal driving with normal turns. I put 8 oz. In because that is what I saw as a recommendation for my differential. Anyway it's good stuff but it stinks. I left the syringe and boxes and empty bottles for him to dispose of!!

Had a Auburn limited slip installed on F-150 a few years ago. Install shop used the Auburn recommended mix of 80-90 non-synthetic hypoid gear oil and Auburn limited slip additive. Axle began to shutter/chatter 300 miles later. Added a bottle of this Motorcraft stuff and problem completely solved.Fast forward to now: The shop that installed the Auburn posi didn’t seal the diff cover very well it would seep around the bolts and collect grime. Finally it began to drip. Decided to change rear axle fluid mostly so I could have a shot at finally sealing the diff cover correctly,This time I used Mobil1 75-140 LS gear oil. That’s full synthetic and is supposed to have limited slip additives included. Chattered bad. Then I added a bottle of KW limited slip additive. Chattered as bad or almost as bad. Then I added a bottle of this Motorcraft stuff. Instantly chatter free yet again!Yes it stinks something fierce. Even after cleaning my oil catch container with brake cleaner and letting it dry outside for an hour the remaining invisible residue stunk up the garage. Wear gloves and be careful so you can minimize drips and residue.But it also WORKS! For my situation it’s been that only thing which has.Side note: Recommend Permatex “Gear Oil Formulated” RTV to seal the diff cover. Good consistently, nice gray color, and is resistant to friction modifiers breaking it down. Rear axle is finally bone dry on the outside.

The product is fine. Works as advertised but the smell is like hypoid gear oil on steroids!My rear diff has a dipstick which also serves as the fill port. Did the job outside, but threw the bottle away in the garage, along with a rag. Wow, the garage and first floor of the house reek, even with all remnants of the job bagged up in the back of the truck outside.Use caution!!

Took 15 minutes to add to 2017 Lincoln Navigator transmission suffering from shudder between 40-55 mph in 4th and 5th gear. Take fill cap and dipstick out of trans while vehicle is running in park with parking brake on and wheel chocked...might as well check fluid color and level while at it. Once that is out of the way, added 4oz to transmission and literally only needed a 8mm to remove two bolts for undertray and a 19 mm wrench to remove the fill/dipstick cap near the catalytic converter. Try not to burn yourself on the converter since the vehicle is running in park with parking brake on but you really would need to try to burn yourself because there is plenty of room. I literally did this on my back in the driveway as soon as my wife got home and it took 15 minutes. I took it for a drive and it steadily and quickly improved in about 10-15 minutes of driving.