FYI FORD - MustangSteve's Ford Mustang Forum
The Internet's Most Knowledgeable Classic Mustang Information
IF YOU HAVE A QUESTION ABOUT CLASSIC FORD MUSTANGS, YOU HAVE COME TO THE RIGHT PLACE!
MustangSteve has over 30 years of Mustang experience, having owned 30 of them and restored several others. With the help of other Mustangers, this site is dedicated to helping anyone wanting to restore or modify their Mustang.... THERE ARE NO DUMB QUESTIONS!!!!!
Visit MustangSteve's web site to view some of my work and find details for:
FYIFORD Contributors' PICTURES - Power Brake Retrofit Kits for 65-66 Stangs - Classic Mustang FAQ's by MustangSteve - How to wire in a Duraspark Ignition - Mustang Ride Height Pictures and Descriptions - Steel Bushings to fit Granada Spindles to Mustang Tie Rods - Visit my EBAY store MustangSteve Performance - How to Install Granada Disc Brakes MustangSteve's Disc Brake Swap Page - FYIFORD Acronyms for guide to all the acronyms used on this page - FYIFORD Important information and upcoming events

You are not logged in. Would you like to login or register?

  • Index
  •  » FYI Ford, Classic Mustang Tech Discussion
  •  » What gear oil for 8" rear end in 65 mustang

    • 1 of 1

       

    5/22/2019 11:03 AM  #1

    Gaba
    Senior 24-7 FYI Addict

    Offline

    From: Van Alstyne Texas
    Registered: 1/15/2014
    Posts: 1,009

    What gear oil for 8" rear end in 65 mustang

    Changing out the third member on my 65 from 2.79 to 3.55.. what gear oil to use? ( open diff)

    If it aint broke, I have'nt tried to "Fix" it yet!
     

    5/22/2019 11:42 AM  #2

    George
    FYI FORD Member

    Offline

    From: Central California
    Registered: 4/01/2013
    Posts: 34

    Re: What gear oil for 8" rear end in 65 mustang

    90wt gear oil

    Cut to fit, Pound to shape, Paint to match
     

    5/22/2019 12:49 PM  #3

    Gaba
    Senior 24-7 FYI Addict

    Offline

    From: Van Alstyne Texas
    Registered: 1/15/2014
    Posts: 1,009

    Re: What gear oil for 8" rear end in 65 mustang

    how much one bottle or two ?

    If it aint broke, I have'nt tried to "Fix" it yet!
       •Thread Starter
     

    5/22/2019 1:19 PM  #4

    Bolted to Floor
    Senior 24-7 FYI Addict

    Offline

    From: Houston, Texas
    Registered: 4/01/2013
    Posts: 2,018

    Re: What gear oil for 8" rear end in 65 mustang

    Buy 2 bottles and fill it up until if comes out the fill hole!!

    John  -- 67 Mustang Coupe 390 5 speed
     

    5/22/2019 3:52 PM  #5

    josh-kebob
    Senior 24-7 FYI Addict

    Offline

    From: Madison, AL
    Registered: 4/06/2013
    Posts: 2,902

    Re: What gear oil for 8" rear end in 65 mustang

    Wear latex gloves when you add that gear oil. Most nasty, stinky stuff ever.

     

    5/22/2019 4:32 PM  #6

    Bullet Bob
    Senior 24-7 FYI Addict

    Offline

    From: Montrose, Colorado
    Registered: 4/01/2013
    Posts: 4,891

    Re: What gear oil for 8" rear end in 65 mustang

    josh-kebob wrote:

    Wear latex gloves when you add that gear oil. Most nasty, stinky stuff ever.

    Actually...while 90 wt is very bad, that friction modifier for a limited slip is about twiced as worser.

    BB

    "you get what you pay for, good work isn't cheap, and there are NO free lunches...PERIOD!"
     

    5/22/2019 8:52 PM  #7

    Steve-G
    I FYI 24-7

    Offline

    From: Glen Rose,TX
    Registered: 4/01/2013
    Posts: 544

    Re: What gear oil for 8" rear end in 65 mustang

    Agree with bolted to the floor. No friction modier needed with am open diff.

     

    5/23/2019 5:45 AM  #8

    TKOPerformance
    Hyper FYIFORD ADDICT

    Online!

    From: Newark, DE
    Registered: 12/15/2014
    Posts: 7,523

    Re: What gear oil for 8" rear end in 65 mustang

    It is the friction modifier that stinks.  The oil smells a bit, but the friction modifier is basically a revenge weapon.

     

    5/23/2019 7:42 AM  #9

    Don
    Senior 24-7 FYI Addict

    Offline

    From: Coppell, Texas
    Registered: 4/02/2013
    Posts: 1,221

    Re: What gear oil for 8" rear end in 65 mustang

    yep  Amsoil is the BEST

    https://www.amsoil.com/shop/by-product/gear-lube/severe-gear-75w-90/?code=SVGPK-EA

     

    5/23/2019 7:56 AM  #10

    TKOPerformance
    Hyper FYIFORD ADDICT

    Online!

    From: Newark, DE
    Registered: 12/15/2014
    Posts: 7,523

    Re: What gear oil for 8" rear end in 65 mustang

    Don wrote:

    yep  Amsoil is the BEST

    https://www.amsoil.com/shop/by-product/gear-lube/severe-gear-75w-90/?code=SVGPK-EA

    Without a doubt.
     

     

    5/23/2019 8:09 AM  #11

    Don
    Senior 24-7 FYI Addict

    Offline

    From: Coppell, Texas
    Registered: 4/02/2013
    Posts: 1,221

    Re: What gear oil for 8" rear end in 65 mustang

    for the last 10 years I have had  a wholesale card.  For individual  orders $100 plus it is delivered to your door.  I sell at cost for friends and am NOT a salesman.  ie  that $18 qt is $14

     

    5/25/2019 8:36 PM  #12

    MS
    Forum Originator

    Offline

    From: Canyon Lake, Texas
    Registered: 1/24/2013
    Posts: 12,297

    Re: What gear oil for 8" rear end in 65 mustang

    3.50:1, not 3.55:1

    Money you enjoy wasting is NOT wasted money... unless your wife finds out.
     

    6/02/2019 4:24 PM  #13

    MS
    Forum Originator

    Offline

    From: Canyon Lake, Texas
    Registered: 1/24/2013
    Posts: 12,297

    Re: What gear oil for 8" rear end in 65 mustang

    Not to sound like Don, but... Is it in yet?

    Money you enjoy wasting is NOT wasted money... unless your wife finds out.
     

    6/02/2019 7:59 PM  #14

    Don
    Senior 24-7 FYI Addict

    Offline

    From: Coppell, Texas
    Registered: 4/02/2013
    Posts: 1,221

    Re: What gear oil for 8" rear end in 65 mustang

    MS wrote:

    Not to sound like Don, but... Is it in yet?

    ??
    Steve   I think it's TIME.  


     

     

    6/04/2019 9:35 AM  #15

    Gaba
    Senior 24-7 FYI Addict

    Offline

    From: Van Alstyne Texas
    Registered: 1/15/2014
    Posts: 1,009

    Re: What gear oil for 8" rear end in 65 mustang

    Nope.. It was a fight to find the right axle seals.. The National brand ones were too small ( by 0.030").. now those are in..

    the old gear is out.. all surfaces cleaned up.. now gonna do E brake cable change.. and then put the new 3.25's in :D

    If it aint broke, I have'nt tried to "Fix" it yet!
       •Thread Starter
     

    6/05/2019 6:24 PM  #16

    Al Newman
    FYI Addict

    Offline

    Registered: 4/08/2013
    Posts: 222

    Re: What gear oil for 8" rear end in 65 mustang

    The original gear oil was 90 wt mineral oil.  It only held up without issue for more years and miles than your new gear set will ever see. Undoubtedly, there are numerous oils now on the market that are viewed as superior.  For a new gear set, best to avoid the synthetics, as it does  not allow the gears to properly introduce themselves to each other.  Otherwise, you really cannot miss with whatever oil you use.  Just depends on how much you want to spend to be comfortable.  Without limited slip, any oils with friction modifier in their blend will give you no advantage but are otherwise useable.
    Best
    Al

    Classic cars are full of surprises and almost none of them are good ones!
     

     

    1 of 1

  • Index
  •  » FYI Ford, Classic Mustang Tech Discussion
  •  »  What gear oil for 8" rear end in 65 mustang

    • Board footera


    REMEMBER!!! When posting a question about your Mustang or other Ford on this forum, BE SURE to tell us what it is, what year, engine, etc so we have enough information to go on.