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

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!!

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!!

Used Royal Purple 75w140 and additive. Rear-end chatter is gone after 75 miles. Will purchase again. Don't mind the odor, you won't smell it again after the job is done.

2011 F-150 with limited slip. The rear end was chattering up a storm, I changed the oil and added the modifier and its smooth as silk. I tried Red Line 1st but it didn't help after about two weeks. This quieted things down after a days worth of driving. Worth every penny.

Great product. Ok packaging. It comes with a plastic snip tip cap also. Very convenient!

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.

Wow!! It works. I rebuilt a 98 Cherokee with a 8.25 Chrysler rear end. I replaced the true track, with a new Auburn limited slip differential. I Set my tolerances and Lash, everything was good to go. The rear end howls at highway speeds, and over several thousand miles I felt it was getting worse. I did have correct lubricants, and a limited slip additive. I tried this Ford stuff, and I have to say I am amazed!! Within a matter of 30 miles, the howl sounds so much better. I won’t lie, it’s still a bit noisy, but with the gearing, differential, tires, and all the stuff you do to a 4x4 some noise is to be expected. However, it is so much quieter, I really feel it is much improved. I heard a lot of chatter about the smell of the product. Yeah, it’s there, but it’s really not near the deterrent to not use this product. and, you’ll have to admit, a rear end with over 260,000 miles on it probably doesn’t smell the best to start with!!That being said, great product, I would definitely use it again and recommend it.

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.