Need help finding gear ratio - Forums at Modded Mustangs
 
LinkBack Thread Tools
post #1 of 16 Old April 21st, 2012, 11:04 PM Thread Starter
Regular
 
DrSunday's Avatar
 
Join Date: Aug 2010
Location: Brooklyn,NY
Posts: 115
 
iTrader: 0 reviews
Need help finding gear ratio

My father bought me this mustang as a gift from ebay. Unfortunately he never wrote down what changes the previous owner made, and I think that he may have changed the gear ratio. Can anyone with upgraded gears tell me about how much rpm they get so I can have an idea if they were changed. Right now with the 89street tune I'm at about 2000-2200 rpm while at 60mph. Thanks for any help
DrSunday is offline  
Sponsored Links
Advertisement
 
post #2 of 16 Old April 23rd, 2012, 12:27 PM
V6inator
 
amustangrocks's Avatar
 
Join Date: Feb 2012
Location: Rockaway Beach Mo
Posts: 126
 
iTrader: 0 reviews
the best way i know of is to remove the diff cover and count the teeth on the ring gear and pinion gear. theres a caculator you can use on this webpage.
Differential Gear Ratio Calculator | West Coast Differentials
you`ll know right away when you see the ring gear. the stock 3.31 ring gear is thin looking, and as a example the 3.73 looks much thicker. theres also a chance the 7.7 got replaced with a 8.8. there should be a sticker on the diff cover also which would give you some clues.
Attached Thumbnails
Click image for larger version

Name:	DSCF1078.jpg
Views:	113
Size:	38.2 KB
ID:	26537  


05 V6 auto base,torch,the"V6inator" jlt/sct/93 race, udp, shorties/jba stainless h/gt muffs, frpp 7.5 t lok/motive 3.73, upr chrome molly rear uca, lca`s,gt brakes, takeoff leather seats, mycolor, amustangrocksleather armrest, e brake, + stuff
amustangrocks is offline  
post #3 of 16 Old April 23rd, 2012, 12:51 PM
M112'd Sixxer
 
Join Date: Feb 2012
Location: Wynyard, SK
Posts: 1,703
   
iTrader: 0 reviews
make a mark on the ds and one on the tire. spin the tire once and count how many times the ds spins.

if a hair over 4 turns... you have 4.10's, hair under is 3.90s, 3 3/4 is 3.73's and 3.5 is 3.55s.


Garage:
1999 Mustang V6 M112 4R70W (Elise) Sponsored by Ortiz Performance
2013 Fiat 500 Turbo C510 (Rosso Rocket)
Fink is offline  
Sponsored Links
Advertisement
 
post #4 of 16 Old April 23rd, 2012, 01:56 PM
V6inator
 
amustangrocks's Avatar
 
Join Date: Feb 2012
Location: Rockaway Beach Mo
Posts: 126
 
iTrader: 0 reviews
i couldnt attach any pics earlier. turning the tires with the marks should tell whats up. looking at the differential means, gasket, sealer and new fluid, which might not be a bad idea depending on how many miles you have. if it has a t lok, you `ll see a "s" clip in the middle, and you`ll also need 4 oz of modifier to add to the gear lube, or royal purple has it in it already.

the first pic is a stock open diff w/3.31. 2nd pic is a t lok w/3.73
Attached Thumbnails
Click image for larger version

Name:	DSCF2014.jpg
Views:	198
Size:	47.8 KB
ID:	26540   Click image for larger version

Name:	DSCF2015.JPG
Views:	119
Size:	83.6 KB
ID:	26541   Click image for larger version

Name:	DSCF1076.jpg
Views:	107
Size:	29.6 KB
ID:	26542  


05 V6 auto base,torch,the"V6inator" jlt/sct/93 race, udp, shorties/jba stainless h/gt muffs, frpp 7.5 t lok/motive 3.73, upr chrome molly rear uca, lca`s,gt brakes, takeoff leather seats, mycolor, amustangrocksleather armrest, e brake, + stuff
amustangrocks is offline  
post #5 of 16 Old April 24th, 2012, 01:59 AM Thread Starter
Regular
 
DrSunday's Avatar
 
Join Date: Aug 2010
Location: Brooklyn,NY
Posts: 115
 
iTrader: 0 reviews
Quote:
Originally Posted by amustangrocks View Post
i couldnt attach any pics earlier. turning the tires with the marks should tell whats up. looking at the differential means, gasket, sealer and new fluid, which might not be a bad idea depending on how many miles you have. if it has a t lok, you `ll see a "s" clip in the middle, and you`ll also need 4 oz of modifier to add to the gear lube, or royal purple has it in it already.

the first pic is a stock open diff w/3.31. 2nd pic is a t lok w/3.73
Yeah I don't want to change all that amustangrocks. My father changed all fluids (including differential) before he gave me it and since then I only did maybe 7k miles. Last time I checked under the car, I did not see no sticker like your first picture posted. Im headed to the shop probably next week, so I'll look for some hidden sticker again while its on the lift.
DrSunday is offline  
post #6 of 16 Old April 24th, 2012, 02:01 AM Thread Starter
Regular
 
DrSunday's Avatar
 
Join Date: Aug 2010
Location: Brooklyn,NY
Posts: 115
 
iTrader: 0 reviews
Quote:
Originally Posted by amustangrocks View Post
i couldnt attach any pics earlier. turning the tires with the marks should tell whats up. looking at the differential means, gasket, sealer and new fluid, which might not be a bad idea depending on how many miles you have. if it has a t lok, you `ll see a "s" clip in the middle, and you`ll also need 4 oz of modifier to add to the gear lube, or royal purple has it in it already.

the first pic is a stock open diff w/3.31. 2nd pic is a t lok w/3.73
Quote:
Originally Posted by Fink View Post
make a mark on the ds and one on the tire. spin the tire once and count how many times the ds spins.

if a hair over 4 turns... you have 4.10's, hair under is 3.90s, 3 3/4 is 3.73's and 3.5 is 3.55s.
Yeah but wouldn't it be different if there was t-lock installed? I'm not sure if there was or wasn't. Also I used the RPM calculator posted and used my tire diameter (28.61) to see what ratio out of the ones you posted have 60MPH rpm of between 2000-2200 and it was 4.10. So I'm guessing mine might be the same. Do you have the 4.10 gears and if so can you tell me around what rpm you get at 60?
DrSunday is offline  
post #7 of 16 Old April 24th, 2012, 11:31 AM
Enthusiast
 
maxwellmurder's Avatar
 
Join Date: Apr 2011
Location: Butler, Pa
Posts: 816
   
iTrader: 0 reviews
Quote:
Originally Posted by DrSunday View Post
Yeah but wouldn't it be different if there was t-lock installed? I'm not sure if there was or wasn't. Also I used the RPM calculator posted and used my tire diameter (28.61) to see what ratio out of the ones you posted have 60MPH rpm of between 2000-2200 and it was 4.10. So I'm guessing mine might be the same. Do you have the 4.10 gears and if so can you tell me around what rpm you get at 60?
i have 4.10's. at 70mph im at 2600 rpms, i can't remember what rpms i'm running at 60. i remember them at 70 because i was just on a 600 mile road trip. also im on stock tires 215/60/17


Diablosport Trinity w/93 race tune from Bama
LTH, X pipe, Hi-Flow Cats, Violators
BBK CAI
T-Lok, 4.10's, 3.5" DS
PATC 3000 RPM Stall Converter
Zex 100 shot



2010 Ford Mustang V6 Coupe: 13.786 @ 99.050 MPH
maxwellmurder is offline  
post #8 of 16 Old April 24th, 2012, 01:56 PM Thread Starter
Regular
 
DrSunday's Avatar
 
Join Date: Aug 2010
Location: Brooklyn,NY
Posts: 115
 
iTrader: 0 reviews
Quote:
Originally Posted by maxwellmurder View Post
i have 4.10's. at 70mph im at 2600 rpms, i can't remember what rpms i'm running at 60. i remember them at 70 because i was just on a 600 mile road trip. also im on stock tires 215/60/17
So I used that calculator & it sounds about right. It says you should be getting about 2500rpm at 70mph. At 60mph it says you should be getting 2130rpm. So probably I have the same gears as you
DrSunday is offline  
post #9 of 16 Old April 24th, 2012, 03:14 PM
Enthusiast
 
maxwellmurder's Avatar
 
Join Date: Apr 2011
Location: Butler, Pa
Posts: 816
   
iTrader: 0 reviews
Check the gear ratio setting in your tune. If they had it tuned for 4.10 gears it should be at 4.10 in the tuner. Like on my Trinity if I would select the axle ratio to adjust it starts at 4.10, when I was stock it started at 3.31


Sent from my tiny computer.


Diablosport Trinity w/93 race tune from Bama
LTH, X pipe, Hi-Flow Cats, Violators
BBK CAI
T-Lok, 4.10's, 3.5" DS
PATC 3000 RPM Stall Converter
Zex 100 shot



2010 Ford Mustang V6 Coupe: 13.786 @ 99.050 MPH
maxwellmurder is offline  
post #10 of 16 Old April 24th, 2012, 04:07 PM
V6inator
 
amustangrocks's Avatar
 
Join Date: Feb 2012
Location: Rockaway Beach Mo
Posts: 126
 
iTrader: 0 reviews
Quote:
Originally Posted by DrSunday View Post
Yeah but wouldn't it be different if there was t-lock installed? I'm not sure if there was or wasn't. Also I used the RPM calculator posted and used my tire diameter (28.61) to see what ratio out of the ones you posted have 60MPH rpm of between 2000-2200 and it was 4.10. So I'm guessing mine might be the same. Do you have the 4.10 gears and if so can you tell me around what rpm you get at 60?
the t lok wouldnt change the gear ratio. marking the driveshaft would be the best bet. my rpm`s would be all messed up, 3.73 gear but 28" tires( vs. stock 27" tires)that are about wore out, so it wouldnt match any calculations.to complicate things even more, my speedo was recalibrated in my tune for 28" tires, so it would really be messed up. i am fixin to get 2 27" tires for the rear for the track this summer, but i`ll have to get the tune changed for the speeedo to be right again. 28.6 is a really tall tire so your loosing some gear ratio but picking up mpg the only sure way to know whats in there is to look inside. maxwells would be about right with the stock tire height and 4.10


05 V6 auto base,torch,the"V6inator" jlt/sct/93 race, udp, shorties/jba stainless h/gt muffs, frpp 7.5 t lok/motive 3.73, upr chrome molly rear uca, lca`s,gt brakes, takeoff leather seats, mycolor, amustangrocksleather armrest, e brake, + stuff
amustangrocks is offline  
post #11 of 16 Old April 24th, 2012, 11:26 PM Thread Starter
Regular
 
DrSunday's Avatar
 
Join Date: Aug 2010
Location: Brooklyn,NY
Posts: 115
 
iTrader: 0 reviews
Quote:
Originally Posted by amustangrocks View Post
the t lok wouldnt change the gear ratio. marking the driveshaft would be the best bet. my rpm`s would be all messed up, 3.73 gear but 28" tires( vs. stock 27" tires)that are about wore out, so it wouldnt match any calculations.to complicate things even more, my speedo was recalibrated in my tune for 28" tires, so it would really be messed up. i am fixin to get 2 27" tires for the rear for the track this summer, but i`ll have to get the tune changed for the speeedo to be right again. 28.6 is a really tall tire so your loosing some gear ratio but picking up mpg the only sure way to know whats in there is to look inside. maxwells would be about right with the stock tire height and 4.10
I was responding to Flink, I think a t-lok would change that method of finding out the ratio from tire spins. I know that would be the best way, but opening it means new sealer and fluid (and the recommended royal purple is impossible to find here so it'll have to be specially ordered). Last time i checked under the car there was no sticker, so it's probably a good sign that it was changed, just don't know to what
DrSunday is offline  
post #12 of 16 Old April 25th, 2012, 12:23 AM
V6inator
 
amustangrocks's Avatar
 
Join Date: Feb 2012
Location: Rockaway Beach Mo
Posts: 126
 
iTrader: 0 reviews
Quote:
Originally Posted by DrSunday View Post
I was responding to Flink, I think a t-lok would change that method of finding out the ratio from tire spins. I know that would be the best way, but opening it means new sealer and fluid (and the recommended royal purple is impossible to find here so it'll have to be specially ordered). Last time i checked under the car there was no sticker, so it's probably a good sign that it was changed, just don't know to what
pretty sure the t lok wouldnt change anything, with both sides jacked up, the t lok would react just like the open diff as the lok doesnt grab till the power is put to it. that should work for the gear, what i dont know is of any other way to tell if it has a t lok in it. i would bet though if it has a gear, it will have a t lok with it. maybe down the road you can open it up, maybe add a chrome cover from cjpony
Attached Thumbnails
Click image for larger version

Name:	DSCF0336 (640x480).jpg
Views:	116
Size:	44.2 KB
ID:	26582  


05 V6 auto base,torch,the"V6inator" jlt/sct/93 race, udp, shorties/jba stainless h/gt muffs, frpp 7.5 t lok/motive 3.73, upr chrome molly rear uca, lca`s,gt brakes, takeoff leather seats, mycolor, amustangrocksleather armrest, e brake, + stuff
amustangrocks is offline  
post #13 of 16 Old April 25th, 2012, 01:53 AM
Enthusiast
 
maxwellmurder's Avatar
 
Join Date: Apr 2011
Location: Butler, Pa
Posts: 816
   
iTrader: 0 reviews
To find out if it has a T-Lok, spray some water I'm your driveway, assuming its paved, put both back tires in the wet spot, and then smash the gas pedal to the floor. Get out and see if you have one or two black marks. Two marks means T-Lok. LOL.


Sent from my tiny computer.


Diablosport Trinity w/93 race tune from Bama
LTH, X pipe, Hi-Flow Cats, Violators
BBK CAI
T-Lok, 4.10's, 3.5" DS
PATC 3000 RPM Stall Converter
Zex 100 shot



2010 Ford Mustang V6 Coupe: 13.786 @ 99.050 MPH
maxwellmurder is offline  
post #14 of 16 Old April 25th, 2012, 02:08 AM
M112'd Sixxer
 
Join Date: Feb 2012
Location: Wynyard, SK
Posts: 1,703
   
iTrader: 0 reviews
tire size or having a t lok make no difference when finding out the gear ratio by the method I posted.

tire spins 1 revolution, DS spins however many times according to what gear ratio is in the rear end.

1. Jack up car, support on stands.
2. mark DS and tire
3. Spin tire once while counting how many times the ds spins.
4. now you know your gear ratio.
5. lower car and do a burnout to find if you have a t lok or not.

15 mins max to accomplish that.


Garage:
1999 Mustang V6 M112 4R70W (Elise) Sponsored by Ortiz Performance
2013 Fiat 500 Turbo C510 (Rosso Rocket)
Fink is offline  
post #15 of 16 Old April 25th, 2012, 05:56 PM Thread Starter
Regular
 
DrSunday's Avatar
 
Join Date: Aug 2010
Location: Brooklyn,NY
Posts: 115
 
iTrader: 0 reviews
Quote:
Originally Posted by Fink View Post
tire size or having a t lok make no difference when finding out the gear ratio by the method I posted.

tire spins 1 revolution, DS spins however many times according to what gear ratio is in the rear end.

1. Jack up car, support on stands.
2. mark DS and tire
3. Spin tire once while counting how many times the ds spins.
4. now you know your gear ratio.
5. lower car and do a burnout to find if you have a t lok or not.

15 mins max to accomplish that.
Oh okay thanks a lot bro . Whether or not I have a tlok is not important at this stage, i just need to get the correct gear ratio for the proper tune.
(Also by DS you mean driveshaft right? Just making sure.)
DrSunday is offline  
post #16 of 16 Old April 25th, 2012, 05:58 PM
I love to skydive
 
Durr4456's Avatar
 
Join Date: Mar 2011
Location: New Orleans
Posts: 17,286
                     
iTrader: 0 reviews
Yes he means driveshaft.

MM is awful. Don't ever come here if you haven't been sucked in already!
Durr4456 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Forums at Modded Mustangs forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome