Modded Mustang Forums banner

1 - 16 of 16 Posts

·
Registered
Joined
·
69 Posts
Discussion Starter #1
hey guys
im about to go with this setup for my gears and have some questions, im just going to get a traction lok 28 spline 7.5 inch setup and 3.73 motive gears for the 7.5, both from american muscle. is this all i need or do i need to buy the bearing kit as well?
the car has 39k miles on it
 

·
muneris pro ego
Joined
·
7,475 Posts
you will need the speedo calibrated for the 3.73 gears, and get the bearing/install kit. anytime you mess with the rear end you need to get one of those
 

·
Registered
Joined
·
7,994 Posts
You can get the install kit, but sometimes the gear shop will have it all. I had the master bearing and still needed some other stuff.
 

·
Danger To Manifold
Joined
·
1,488 Posts
The bearing kit is for over 30k miles. Don't forget a speed cal or tuner to reset your gear ratio. The tuner would be the better choice.

Also make sure that you either buy Ford gear oil and the friction modifier or the royal purple from AM. You don't need the friction modifier if you go with royal purple.
 

·
Registered
Joined
·
69 Posts
Discussion Starter #7
ok so i do need the bearing kit? and how much will it really affect my speedo cuz it might be a while before i save up the money for the flash tuner...
 

·
Danger To Manifold
Joined
·
1,488 Posts
I'm not sure what the change in ratio will do to your speedometer. I believe it will make your speedometer read slower than you are moving.
 

·
Registered
Joined
·
69 Posts
Discussion Starter #9
ok as long as its only a few mph's off then it should be fine for the month or so until i get the tuner
 

·
Registered
Joined
·
7,994 Posts
Mine was only off by a couple mph, and when i got to about 60 or so it was saying i was doing like 68 ish. If youve driven enough, youll know what a certain mph feels like without lookin at the speedo.
 

·
Safud: MM's Resident Hadji
Joined
·
5,242 Posts
Mine was only off by a couple mph, and when i got to about 60 or so it was saying i was doing like 68 ish. If youve driven enough, youll know what a certain mph feels like without lookin at the speedo.
+1

Also...Your milage will go faster with steeper gears and no tune. So basically every mile you go you'll gain like 1.4 (guesstimated number) miles on the odometer
 

·
Zoolander
Joined
·
7,719 Posts
If your having the rear worked on get a bearing kit anyways. I wouldn't want to re-use parts just because someone says it's ok for this period of time, especially in the differential.
 

·
Zoolander
Joined
·
7,719 Posts
I'm not sure what the change in ratio will do to your speedometer. I believe it will make your speedometer read slower than you are moving.
Nope. Says your going faster. When I had 4.10s installed in my GT(still miss that car sometimes) at about 60mph said I was doing 90mph.
 

·
Registered
Joined
·
69 Posts
Discussion Starter #14
thanks guys
 

·
Registered
Joined
·
7,994 Posts
Nope. Says your going faster. When I had 4.10s installed in my GT(still miss that car sometimes) at about 60mph said I was doing 90mph.
Really? mine wasnt off that bad, maybe 10mph but not 30.
 

·
Registered
Joined
·
389 Posts
You can calculate what speed it'll show for different mph. Currently, you have 3.27 gears, and you want 3.73 gears. If you want to know how far off the speedo will be at 60 mph, multiply the speed by (3.73/3.27). 60 * (3.73/3.27) = 68.4 mph. So your speedo will be off by 8.4 mph at 60. At 70 mph, it'll be off by 9.8 mph. I think you see the trend...
 
1 - 16 of 16 Posts
Top