hello...i am doin a fluid change on the ex and read some conflicting info..i bought the friction modifier but read that most manufacturers have it already in it .Is there any harm in adding it anyway or will it affect the limited slip???
thanks,Marc

 

You are supposed to use synthetic 75-140 on the rear differential. All synthetics that I found already had friction modifier in it. I went with mobil-1 and added no friction modifier and it works well. Even seemed to improve my MPG a little. Definitely smoother. The crap that ran out of the differential after only 60,000 pampered miles was pretty impressive. Makes me wonder how they can ever say that the diff. fluid is good "for the life of the vehicle."

 

Just changed mine after 125000 miles with royal purple. Just droped right in.

 

thanks for the info...i have quaker state 75w140 synth.i guess i dont need the additive

 

Not all the fluids have modifier and some brands can be bought either way. The best way is if you can get away without it so your clutches will grab good. What it does is makes the oil slipperier and the trick is to try it without and slowly add it until your clutches quit chattering. The safe and easy way is to just throw the heavy synth in there that contains the additive but the best way is to add regular synth and then modifier until your clutches quit chattering (if they do chatter). It is only needed in limited slip differentials and a waste in any other types.

 

It should say on the bottle if it has modifier in it or not.

 

Yes, and some say LS after the weight or the brand.