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Royal Purple Max Gear 75w140 Gear Oil

Market Price $24.99 You Save 17% ($4.31)
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FREE Shipping on orders over $49
  • Item 45006
  • MPN# 1301

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Features & Details

  • Fully Synthetic
  • Friction Modifier Included
  • Protects Against Wear
  • Reduces Gear Whine
  • 75w140 Weight
  • 8.8" Ford Rear Ends Require 3 Quarts
  • For 1979 to 2017 Mustangs
Pure Performance. Maximize performance from your Mustang's drivetrain with Royal Purple Max Gear oil. This fully synthetic oil is the perfect complement to new gears, lubricating better and ensuring your differential keeps working its best whether it has gone a thousand miles or a hundred thousand.

Protect Your Investment. Made with Royal Purple's innovative Synslide® additive, Max Gear oil is perfect for upgrades or routine service. It's the gear oil of choice for greater wear protection and lower temperatures for every car, from daily drivers to track-day toys. It prevents corrosion and meets all warranty requirements, so adding Royal Purple Max Gear oil is great for peace of mind when it comes to your Pony.

Includes Friction Modifier. Unlike other oils, all viscosities of Max-Gear® are formulated with hypoid friction modifiers necessary for use in clutch or cone type differentials. No additional additives are necessary.

Application. Royal Purple Max Gear 75w140 weight oil is recommended for use in 1979 to 2017 Mustangs and is compatible with other oils. Three (3) quarts of gear oil are required to fill a 8.8" Ford rear end.

Fitment: 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Details

What's in the Box
  • (1) one quart bottle
Installation Info
Will it fit my Mustang?
  • Boss 302 - 12, 13
  • Foxbody - 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93
  • Mach 1 - 03, 04
  • V6 - 94, 95, 96, 97, 98, 99, 00, 01, 02, 03, 04, 05, 06, 07, 08, 09, 10, 11, 12, 13, 14, 15, 16, 17
  • Bullitt - 01, 08, 09
  • Cobra - 94, 95, 96, 97, 98, 99, 01, 03, 04, 93
  • GT - 94, 95, 96, 97, 98, 99, 00, 01, 02, 03, 04, 05, 06, 07, 08, 09, 10, 11, 12, 13, 14, 15, 16, 17
  • GT500 - 07, 08, 09, 10, 11, 12, 13, 14
  • EcoBoost - 15, 16, 17
  • GT350 - 16, 17

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Most Helpful Reviews

Slide N' Glide

This is the last oil you'll ever want to buy. Before on the same hill I would hit the gas pedal to get the stang moving after upgrading to Royal Purple completely throughout my Stang, I've noticed a huge ...

Read More
Helpful (1)

Royal purple gear oil

I have used Royal purple 75w140 gear oil a couple of times once for new gears and again after the gears "break in period" and I am happy with the results,

Helpful (1)

Overall Rating 4.9 out of 5 stars
Read All 52 Reviews

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6 Questions / 8 Answers

Ask a Question

For my 2009 GT how many quarts do I need plus the friction modified


Helpful (0)
  • Thank you for your question about the Royal Purple Max Gear 75w140 Gear Oil. Three (3) quarts of gear oil are required to fill a 8.8" Ford rear end.


How much gear oil and friction modifier for 2007 Mustang GT?


Helpful (0)
  • Hello! An 07 GT takes 2 quarts of Gear Oil, and 4 oz of Friction Modifier.


how many quarts does the rear differential take to fill up 2016 Mustang and the weight of oil the stock one take thank you


Helpful (0)
  • A 2016 Mustang will require 2 Quarts of Gear oil with no rear cooler option, with the rear cooler, 3 quarts will be required. both will also require friction modifier. OEM the axles come with Motorcraft® SAE 75W-85 Premium Synthetic Hypoid Gear Lubricant.

    Rob D

For a 99 gt 8.8 diff. Would 2 quarts and a bottle of friction modifier be enough or would I have to make that 3 quarts and the modifier?


Helpful (0)
  • The friction modifier is already added to the Royal Purple gear oil so you would not need to add anymore separately. Also, I would recommend using 3 full quarts of the gear oil to to fill the 8.8 rear end.


I am wondering ....why is it that it says I need 3 quarts of gear oil for my 8.8 rear end? But the Gear Kit only includes 2 quarts and friction modifier, which it also says comes in the Royal Purple Gear oil ? I just ordered 3 qts. and seems as I may end up with a spare!


Helpful (0)
  • As per the manual the 8.8 rear takes 4.25 pints so you will need the 3rd quart for that extra 4oz. Do not over fill or you will have fluid coming out of your axel seals sooner or later. Happy Motoring!


Is a Friction modifier really needed? I have heard varying opinions on the subject. I know it says it has all modifiers necessary already added, but some folks have told me that they still add it. I have a 2006 v6 that I'll be swapping an 8.8" rear w/4.10s into. I just want to be sure I take all of the necessary precautions to ensure that my almost new take off rear has a long life. Thanks!


Helpful (0)
  • The friction modifier needed is already added to this Royal Purple Gear Oil. You don't need to add more modifier for it to work properly. That said, it can not hurt your rear by adding some additional modifier. So, it's not necessary to add more but you can for added piece of mind if you wish to. Hope this helps!


Show 2 more answers

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Customer Reviews (52) Write a Review

Overall Rating 4.9

out of 5 stars

Installation Time:Afternoon

Installation Cost:$100-$250

  • Performance Gain 4.53125 4.5
  • Fit 4.939394 4.9

  • 5/5

    Installation Time: Afternoon

    February 18, 2017

    No friction modifier needed.

    At first I was concerned about filling up my diff with this without friction modifier but since the bottle said that it already had I decided to give it a go without the friction modifier. It's been about 2 weeks now and no noise or groaning from the diff. It seems that royal purples claims are true, you don't need friction modifier, but make sure you buy three bottles for the 8.8 rear.


    Year: 2001 Submodel: Bullitt

    Helpful (1)

  • 5/5

    February 17, 2017

    Royal purple gear oil

    I have used Royal purple 75w140 gear oil a couple of times once for new gears and again after the gears "break in period" and I am happy with the results,


    Year: 2005 Submodel: Other

    Helpful (1)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $250-$500

    May 24, 2013

    Great product

    I used this in my Ford Racing 3.73 gears and Auburn limited slip differential swap into the stock 7.5 inch rear end. So far, the Royal Purple has worked well--no gear whine. Mind you, i'd decided to put some Ford Racing friction modifier in the differential as well, so I can't comment on just using the Royal Purple alone, but some people have reported a bit of gear whine with just the Royal Purple.


    Year: 1999 Submodel: V6 Winnipeg, MB

    Helpful (1)

  • 4/5

    Installation Time: Afternoon

    February 11, 2013

    Royal purple FTW

    royal purple makes great oils/lubricants. Their gear oil is no exception, it does what they intended it to. Provides great lubrication for my diff/gears.


    Year: 2011 Submodel: GT pa

    Helpful (1)

  • 5/5

    January 15, 2013

    Just coast

    I used this when I did a fluid swap in the rear end on my 8.8. Great product I also have the Syncromax in the Tremec 3650. No driveline noise whatsoever on my 2002 GT. When I lift off the accelerator the car maintains its speed it is so smooth.


    Year: 2002 Submodel: GT Wilmington, NC

    Helpful (1)

  • 5/5

    Installation Time: Afternoon

    November 26, 2011


    Installed 3.73 motive gears and used 2 bottles of royal purple on my 2002 GT . Works great. Shipping was free and really fast. Thank you American Muscle


    Year: 2002 Submodel: GT Tolleson, AZ

    Helpful (1)

  • 5/5

    Installation Time: Afternoon

    September 02, 2011

    Used with Gear Install

    Price is better here than what I have seen in retail shops local to me. Worth going PURPLE!


    Year: 2003 Submodel: GT Wayne, PA

    Helpful (1)

  • 5/5

    May 12, 2011

    Slide N' Glide

    This is the last oil you'll ever want to buy. Before on the same hill I would hit the gas pedal to get the stang moving after upgrading to Royal Purple completely throughout my Stang, I've noticed a huge difference in fuel economy and the gas I have to use down/up the same hill to get my Stang moving. Pretty slick huh. Not to mention that synthetic preserves your cars internal parts better than the other stuff.

    Jose Becerra

    Year: 1998 Submodel: Other

    Helpful (1)

  • 5/5

    Installation Time: Less than 1 Hour

    February 18, 2012

    Motion Lotion

    I have two words for you " ROYAL PURPLE ". It's a no brain'r these guys wrote the book on Performance Lubricants. Don't waste you time looking any where else. Do it once, Do it right, Do it Royal Purple, Case Closed!


    Year: 2007 Submodel: V6

    Helpful (10)

  • 5/5

    July 16, 2010

    Awesome Product

    Put this in the rear differential of my 2006 mustang V6, also put the synchromax in my transmission, along with Valvoline SynTech in the engine. At cruising speed, can't even hear or feel ANY gear noise. Full throttle pulls feel velvet smooth, can't believe how good this product is!


    Year: 2006 Submodel: V6

    Helpful (10)

  • 5/5

    October 15, 2010

    GO PURPLE!!!

    This gear oil is absolutely awesome! When I did a full rear axle/gear swap 3 months ago & upgraded from stock to Motive 3.90s, I used this gear oil for the install. Well, 3 months later & no wine, no grinding noises, & silky smooth shifts. Going Purp is the only way to go!

    Diego Walker

    Year: 1990

    Helpful (7)

  • 5/5

    Installation Time: Less than 1 Hour

    January 25, 2012

    Great reputable product for my 2008 GT

    I installed new FRRP 4:10s myself (I do all my own work) and used Royal Purple 75w90 for the 500 mile break in period. After the break in period, I removed the cover, inspected the ring gear and put it back together. I then filled the diff with Royal Purple Max Gear 75w140 weight oil. I plan on reinspecting at 10K miles. The car accelerates much better than with the factory 3:55s. Has a little bit more whine than the stock gears, but my rear supension is not stock either and transfers more noise. To protect my new rear set up I chose Royal Purple because of the temperature and low friction properties (slippery) + I did not have to worry about a friction modifier adder. I buy the majority of my high perfomance components from American Muscle. Good prices, quick delivery and great customer service. A supercharger is next...!


    Year: 2008 Submodel: GT Ohio

    Helpful (4)

  • 5/5

    Installation Time: Shop Install

    January 07, 2012

    Satisfied coupled with Ford Racing 3.73 Rear Gears

    No Gear wine or chatter with new set of Ford Racing 3.73 Rear Gears. Shifts are nice a smooth.


    Year: 2006 Submodel: GT Allentown, PA

    Helpful (3)

  • 5/5

    October 15, 2010

    75w140 Gear Oil

    The Royal Purple 75W140 Gear Oil is the absolute best quality gear oil that you can buy--bar none. I have used RP's manual transmission oil as well for the past three years and it is smooth, smooth, smooth shifting. You cannot go wrong when buying Royal Purple. It is the best on the market...fullstop!

    Steve N

    Helpful (4)

  • 5/5

    Installation Time: Less than 1 Hour

    March 05, 2012

    Royal Purple is the way to go

    i had my T-Lok and 4.10 gears installe at my local dealership and the mechanic told me to get the Royal Purple instead of going with motorcraft and ford's friction modifier. I used the 75w90 for my break in period and switched to the 75w140 for the rest of the life of the car. you cant go wrong with Royal Purple products!!!


    Year: 2010 Submodel: V6 Butler, PA

    Helpful (2)

  • 4/5

    Installation Time: Afternoon

    April 17, 2013

    Great fluid but...

    I have 4.10 gears already and had no audible whine before installing a new pinion seal. After I had a very audible whine. Took a Saturday afternoon with the shop manager and we opened the whole rear-end and replaced the crush collar and bearing races. The majority of the whine went away and the rear feels more solid than ever with this new fluid in!


    Year: 2005 Submodel: GT Dover, DE

    Helpful (1)

  • 5/5

    October 14, 2010

    the best gear oil

    i but this product like 2 or 3 months ago when i do my 3.55 geras isntallation and it seems to be working good no problems at all ... i will recomend to use when ur doing gears or just oil change..


    Helpful (3)

  • 5/5

    September 28, 2009

    No complaints

    Bought to change my rear diff cover to the girdled style and for my axle bearing change. No complaints other than the bottle's lid could use a better design; flimsy and leaks a little around through the threads when you're trying to squeeze it out into the differential. Call me wierd, but I like the smell! Supposed to be the best there is and run cooler. Rear diff girdled cover will likely bump you up to 2.5 quarts on refill, so get three if you change your stocker!


    Helpful (1)

  • 5/5

    October 15, 2010


    Worked perfect! no problems! 5 stars

    Eric R

    Helpful (0)

  • 5/5

    October 14, 2010

    cool color

    more fluids should have cool colors. i've always had good luck with all sorts of royal... royal purple, crown royal... mmmmm great products the both :D


    Helpful (0)