80301 Limited Slip Friction Modifier - 4 Ounce

Worked like a charm but you have to spend 20 minutes doing figure 8's at slow speed. Solved the drag sound.

As always Red Line is a top tier product. I use Red Line 75W90ns gear oil for the rear diff in the race car the ns in the oil name stands for Non-Limited Slip. That way I can add the Limited Slip Friction Modifier and I can fine tune the slip/grip that the rear tires get. This came from the Red Line store so I was fairly certain it would get to me on time. It was supposed to arrive in 5 to 7 days but it only took 2 days. None of my local stores had this in stock and it was going to be weeks before they could get it.

Helps with the rear end noise

This stuff is a necessary evil if you have a limited slip. Once installed, the benefit was obvious. However, I would design the spout differently. Its easiest to install differential fluids by using a rubber hose and just tilting the bottle on end. The spout on this bottle does not allow for the attachment of a rubber hose. I had to squirt it into the hole and it was a mess. I guess an alternative would be to mix it with the differential oil before putting it in the differential, but my differential was already full of oil. Good product, but why not put a cone spout on the bottle?

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I saw a lot of info saying to use the Ford limited slip modifier for my 8.8 rebuild, but it's $70 a bottle. I trust Redline, so I bought this and used it. I soaked the limited slip clutches in it for two weeks, and installed them and poured the modifier in the rearend. The first few days I had some rubbing in the rear, but it's settled in nicely and rarely grunts. I'll definitely use it again.

Works great in my Ford 8.8 Traction-Lok rear axle when mixed with Mobil 1 75W-140 synthetic gear oil. The spout meant well but wasn't long enough to pour into the axle fill hole; still had to use a pump like with the oil itself. Many synthetic gear oils claim they already have "limited slip additive" included, but it is usually not enough for optimal performance. If your vehicle says that a friction modifier additive is needed, then make sure you add some (might not need the whole 4 oz, but will probably need at least some) even if the gear oil says it's not needed.

My 2011 M3 developed a slight noise after I changed out the factory diff fluid with Castrol Syntax without friction modifier in it. After a month or so, the noise got a little big more pronounced. I added about .5-.75 ounce of this fluid and the next drive the noise was gone. Due to the fact that you don't need much of this fluid, I wasn't completely surprised to see that someone had poked a very small hole in the plastic sealing ring and sucked out some fluid prior to me receiving it. I suppose I should have big-dealed it with Amazon, but in reality, it met my needs and I probably won't use the remaining portion ever again. Or at least not for another 50k.

Added to grand cherokee rear differential, worked as expected.

Este modificador de frucción me ha ido fantástico en el diferencial autoblocante trac lok de mi grand cherokee zj. Se han acabado los ruídos que tenía porque se enganchaban.los discos. Aunque tenía aceite 75W140 especial para autoblocante, no hacía bien su función. Saqué 110ml de aceite y lo sustituí por este botecito, y mano de santo. Si tienes ruídos o crujidos raros en el autoblocante, no dudes en ponerlo, serás feliz

I fitted a limited slip differential gearbox to my mini which creaked and moaned and groaned when turning slowly. Added half a bottle of this to the oil in the gearbox and the problem was gone instantly.

Habe den Zusatz beim Ölwechsel meinem Limited Slip Differential beigemischt wie vorgegeben. Die Menge der (überraschend kleinen) Flasche enstpricht genau der vorgeschriebenen Menge (118ml). Konnte bislang keine Probleme feststellen, es erfüllt seinen Zweck.

This thing works like magic. My LSD differential (M3 e92) started to chatter and make noise on tight turns after replacing the fluid, and it kept getting worse and worse. So i replaced the oil again and added this FM and problem is solved. However, it might be a good idea to only add half a bottle first and see if it solves the problem. I added one complete bottle and feel like the LSD locks a bit less than before (less fun :) ) so i will drain a little bit of the oil (half a liter) and add some new oil maybe the locking is stronger again. But this is perfect, i was worried the differential was going bad.