You have to be careful with the Redline, they actually make 2 gear lubes. One with the modifier, and one without. I added the incorrect one to my turbo SE-R and has issues with the viscous limited slip. I switched to the non additive, and it fixxed itself.

 

I totally disagree......RP,RL,and Lucas are way cheaper then Motorcraft gear lube,by almost $10.00! They also do not add enough FM,IMO! I've had several Ford vehicles with LS and used RL and RP and they still chattered.After adding a 4oz bottle of Ford FM everything was ok and quiet.I also have some friends that are Ford and Chevy techs that also agree with adding the FM.
About the Mag cover,thats an excellent idea! Everything you've stated is more beneficial to extending the life of the differential!

 

I have the limited slip differential in my '01 Screw. A couple of months ago I had a shop change the fluid. The truck now shudders a little when I take off from a stop with the wheels turned. It does not seem to do it when I start off strait. I am wondering if the shop did not use the friction modifier. What do you guys think? Will have caused any damage if they didn't?

Thanks.

 

Did you call and ask them if they added it? Just to be safe you can add the required 4oz. recommended and see if that fixes your problem.If not take it back to them!

 

Well I double checked my receipt and it shows they used a Valvoline synthetic that is supposed to have the modifier in it. Further investigation is going to be required.

 

As I stated before,even the lubes that claim to have a modifier in them still do not have enough required to keep the differential quiet!

 

this sounds like a nice piece to add.

 

hmmm now I'm confused on what to use.

 

Opinions on lubrication are like butt holes, everyon has one. You really can't go wrong with any of the quality synthetic gear lubes. Pick one that fits your budget, and personal choice. Make sure to ad the Ford friction modifier, even if the lube claims to have it already. You should be all set.

 

What about lubrication for the butt hole?

You want real confusion? Read all you can about motor oil. Motor oil debates have been going on since before they invented the wheel.

Check out bobistheoilguy.com

 

Bought a Mag-Hytec last February and I'm finally putting it on this Friday, cant wait. Was going to go with the RP straight but now I'm wondering too if I should add some Ford FM. I'll keep searching.

 

I am jealous. Wish the Mag-Hytec would fit on my Exped. I would definitely go ahead and ad the FM, cheap insurance.

 

I actually just did mine, 3.73 LS. Put the silicone gasket on the cover waited a while befoe filling er up. put Valvoline 75-140 fully synthetic gear oil, and the FM in it. No probs yet (knock on wood, )

 

Many synthetics are chatterless in many limited slips without FM, but many also chatter. You have to look at it on a case by case basis. Thing is, the FMs decrease the oil's oxidation resistance, meaning the oil will degrade faster in heat with FM than without, and the more FM you add the worse it is. On one hand, you gotta have it to avoid chatter, on the other hand you are decreasing the potential life of the oil. Hobson's choice You really can't have it both ways in this case, so the things to do are:

a) RE a synthetic, try it without first and add as needed,

b) after an oil change to synthetic, go out and drive around a bit to heat up the oil, do some figure 8s to get the oil worked into the unit before condemning it. Even with FM, sometimes it takes a little while (a few miles, plus the figure 8s) for it to work it's way into the clutch packs,

c) add the minimum amount possible to eliminate chatter.

 

I had a lube shop change the diff fluid without and it chattered a lot. I added 2 bottles of FM and chatter was completely gone within 1 week of driving. 1 year later still runs great.