Royal Purple Diff Oil and "Friction Modifiers"

[4VFTW]

If you change your Diff Oil to Royal Purple be advised that it contains friction modifiers already and you should have no issue with chatter. If you do experience some chatter and decide to add additional modifier to the rear DO NOT just dump a 4oz bottle into the rear... you only add as much modifier as is required to eliminate the chatter.

Adding 4oz to a oil that already contains modifiers may very well make the oil too slick which will cause the clutches to disengage/not engage when they should.You will think you cured the problem, but may have just created another problem that makes it seem better.


FWIW I have used Royal Purple alone in my current car and in my old Fox with no chatter issues.

 

[blackbeast12]

When i had my Whiteline watts link installed i had my installer put Amsoil 75-140 severe gear extreme pressure synthetic gear oil in and a separate 4 ounce bottle of Amsoil friction modifier. My rear is quiet, and i even picked up a few miles per gallon! Great stuff it has a 100000 mile change interval!

AMSOIL Severe Gear® 75W-140

AMSOIL Slip Lock Gear Oil Additive

 

[Rct851]

And heeeere we go

 

[burke985]

When i had my Whiteline watts link installed i had my installer put Amsoil 75-140 severe gear extreme pressure synthetic gear oil in and a separate 4 ounce bottle of Amsoil friction modifier. My rear is quiet, and i even picked up a few miles per gallon! Great stuff it has a 100000 mile change interval!

AMSOIL Severe Gear® 75W-140

AMSOIL Slip Lock Gear Oil Additive

About to do the same thing when i get home from work and use the same stuff , im hoping it quiets the 3.73's down a bit on decel

 

[Blazer707@TBR]

When I installed my 3.73's I used royal purple and saw they had friction modifier in the fluid. I still added a 4 oz bottle just incase.

I would always recommend to add the small bottle just for good measure.

Sent from my SAMSUNG-SGH-I747 using Tapatalk 2

 

[pohnjarker]

When i had my Whiteline watts link installed i had my installer put Amsoil 75-140 severe gear extreme pressure synthetic gear oil in and a separate 4 ounce bottle of Amsoil friction modifier. My rear is quiet, and i even picked up a few miles per gallon! Great stuff it has a 100000 mile change interval!

AMSOIL Severe Gear® 75W-140

AMSOIL Slip Lock Gear Oil Additive

had the exact same thing done when i changed my gears a couple weeks ago.

 

[CPRsm]

FWIW I have used Royal Purple alone in my current car and in my old Fox with no chatter issues.

Royal purple w their modifier is not enough. I haven't found anyhing that works other than Ford modifier, and it takes two bottles sometimes.

Worked in your fox because they weren't the same clutches they use in these cars. '05 and up need to use the good shit from Ford.

If you don't use the right modifier it takes about a week for it to show since you don't constantly drive in circles.

 

[WHSTLR]

If you change your Diff Oil to Royal Purple be advised that it contains friction modifiers already and you should have no issue with chatter. If you do experience some chatter and decide to add additional modifier to the rear DO NOT just dump a 4oz bottle into the rear... you only add as much modifier as is required to eliminate the chatter.

Adding 4oz to a oil that already contains modifiers may very well make the oil too slick which will cause the clutches to disengage/not engage when they should.You will think you cured the problem, but may have just created another problem that makes it seem better.


FWIW I have used Royal Purple alone in my current car and in my old Fox with no chatter issues.

The statement I bolded, Where did you get this information"? Is this your educated guess or did someone you consider a professional tell you this?

 

[4VFTW]

The statement I bolded, Where did you get this information"? Is this your educated guess or did someone you consider a professional tell you this?

it comes from the understanding of how a limited slip diff functions and how friction modifier affects that function... If you have conflicting info, please post it up.

 

[Riptide]

Used valvoline synth and no ford modifier for years. No chatter.

Added a 4oz. bottle of the ford FM. Took the car to the track. One tire fire in the burnout box.

Drained it last night. Refilling tonight. Will see if that solves the issue. Not adding any extra modifier.


Sent from my iPhone using Tapatwat

 

[4VFTW]

Used valvoline synth and no ford modifier for years. No chatter.

Added a 4oz. bottle of the ford FM. Took the car to the track. One tire fire in the burnout box.

Sent from my iPhone using Tapatwat

This is exactly what can occur from using more friction modifier than needed.

 

[Riptide]

Right. Hoping my clutches survived that little screwup. Won't know until I get a chance to test it. If its trashed time for a trutrac.


Sent from my iPhone using Tapatwat

 

[WHSTLR]

it comes from the understanding of how a limited slip diff functions and how friction modifier affects that function... If you have conflicting info, please post it up.

No conflicting info. I know you CAN have too much modifier as well as too little however, I thought you may have had some factual information based on the amount/type of modifier RP has in it coupled with adding the Ford Modifier. There have been many discussions on multiple forums about this and no one ever really has a definitive answer. RP says "No additional modifier needed". Yet some have had reported issues on many different vehicle platforms. You will find plenty of threads on this. Makes me wonder if the amount of modifier put into each bottle is being properly measured?

 

[4VFTW]

No conflicting info. I know you CAN have too much modifier as well as too little however, I thought you may have had some factual information based on the amount/type of modifier RP has in it coupled with adding the Ford Modifier. There have been many discussions on multiple forums about this and no one ever really has a definitive answer. RP says "No additional modifier needed". Yet some have had reported issues on many different vehicle platforms. You will find plenty of threads on this. Makes me wonder if the amount of modifier put into each bottle is being properly measured?

No I have no knowledge of the chemical composition or the % of modifier RP uses , but I find it difficult to imagine their QC is so poor that the quantity would vary significantly from batch to batch.

 

[UnleashedBeast]

Royal purple w their modifier is not enough. I haven't found anyhing that works other than Ford modifier, and it takes two bottles sometimes.

Worked in your fox because they weren't the same clutches they use in these cars. '05 and up need to use the good shit from Ford.

If you don't use the right modifier it takes about a week for it to show since you don't constantly drive in circles.

I agree, good friction modifier is the key. Amsoil Slip Lock will make your rear diff clutches quiet when using 2 to 4 ounces. It's really good stuff.

However, too much modifier can alter the proper operation of the differential. Too much is not a good thing. Using Amsoil Severe Gear without additional FM will result in slow speed corning differential chattering that can be heard when your windows are down and the stereo is off. Normally, I add 2 ounces of additional FM and this clears it up.

 

[WHSTLR]

No I have no knowledge of the chemical composition or the % of modifier RP uses , but I find it difficult to imagine their QC is so poor that the quantity would vary significantly from batch to batch.

Yeah thats the part of that theory I have the hardest time with also. But there has to be some factor that can be identified. And it may be user error! Although I would hope not. That would make a large number of people (auto community not just mustangs) look really bad!