Red Line 80301 Limited Slip Friction Modifier - 4 Ounce

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.

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.

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.

thank you

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

I would not buy this product again, very dissatisfied, not allowed to say why!

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?

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.