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How can I determine axle ratio ?

2K views 11 replies 7 participants last post by  mudbug85603 
#1 ·
Bumping up from 31" to 33" and want to make sure the wife does not get a ticket.
Plan to put a new speedo gear in but, I guess I need to confirm the ratio to get the correct gear.
As far as I know everything regarding that is stock.

1998 Sahara 4.0 with automatic transmission.

Thank you for the help.
 
#2 ·
pull the cover and count the teeth on the pinion and ring gear. Divide the ring gear teeth number by the number of teeth on the pinion.

or

Raise the vehicle and rotate the wheels by hand in the same direction while the transfercase or transmission is in neutral. Mark the driveline and count the number of rotations the drive line makes while making one full turn of the wheels. For example, 3 3/4 turns would be approx 3.73 .

or

Look at the tag on the differential. It should be stamped on the metal tag attached to one of bolts.

My guess would be 3.73. Dont worry about getting a ticket. Auto trans and 33's you will not be going anywhere super fast. Your speedo will be approx 5mph slow
 
#3 ·
#5 ·
You betcha! I found it here somewhere and bookmarked it. I've been giving it a real workout lately in my search for the perfect TJ :)
 
#6 ·
Thanks Finger Waggle !

This is what the site provided :

Equipment Listing
VIN 1J4FY49S4WP788046
Vehicle Description 1998 JEEP WRANGLER 4X4 SPORT UTILITY 2-DR
Monotone Paint
Power Front Disc/Rear Drum Brakes
Reclining Front Seats
Next Generation Front Air Bags**
Passenger Air Bag On/Off Switch
Front Seat Area Carpet
Cargo Tie Down Loops
3-Spd. Automatic 32RH Transmission
Command-Trac Part Time 4WD System
Dana 30/186MM Front Axle
Dana M35/194MM Rear Axle
Tinted Windshield Glass
Swing-Away Mirrors
Instrument Cluster w/Tach
100 MPH Primary Speedometer
Dual Note Electric Horns
12V Auxiliary Power Outlet
Locking Glove Box
Lt. Quartz - Badge - Jeep, Lower Cow
Lt. Quartz - Badge - Wrangler
EXTERIOR COMPONENT COLOR
Halogen Headlamps
CHMSL Lamp
Black Front Bumper
STANDARD EQUIPMENT
Black Rear Bumper
Bumper Extensions
Chrome Headlamp Bezels
Black Front Frame Overlay
Body Color Grille
Sport Bar w/Side Padding
EVAP Control System
Moss Green Pearl Coat
Power Steering
Front Stabilizer Bar
Rear Stabilizer Bar
Outside Tire Carrier
Goodyear Brand Tires
Upgraded OBD-II Connectors
Fuel Tank Skid Plate Shield
Transfer Case Skid Plate Shield
Tethered Fuel Filler Cap
Build To U.S. Mkt. Specifications
GVW Rating - 4450#
U.S. Dealer Retail
Zone 63-Dallas
Texas Ship to State Code
Texas Sold to State Code
Prem Cloth Hi-Back Bucket Seats
Saddle/Moss Green
Tire & Wheel Group - 30"
Convenience Group
OPTIONAL EQUIPMENT
Heavy Duty Electrical Group
DO NOT USE - see sales code AEN
Sahara Decor Group (97-02-26)
4.0L Engine(ERH)/3Spd Auto Trans(DGG
117 Amp Alternator
600 Amp Maintenance Free Battery
High Back Bucket Seats
Easy Access Pass Tip & Slide Seat
Rear Folding Seat
Rear Seat/Wheelhouse/Cargo Carpet
Cowl Side Carpet
Front Floor Mats
Sport Bar w/Rear Padding
Full Length Floor Console
All 3-Speed Automatic Transmissions
Lock-Up Torque Converter
3.73 Rear Axle Ratio
All Engines
4.0L I6 Power Tech Engine
Light Tint Front Door Windows
Deep Tint Sunscreen Windows
Full Metal Doors w/Roll-up Windows
Rear Window Defroster
Left Manual Mirror
Right Manual Mirror
All Vehicles W/O Power Mirrors
Air Conditioning
Var Intermittent Windshield Wipers
Rear Window Wiper/Washer
STRIPE/BADGE/MOLDING/COLOR
Lt. Quartz - Badge - 4.0L
Courtesy Lamps
Rear Cargo Lamp
Underhood Lamp
Fog Lamps
Bodyside Side Steps
Federal Emissions
19 Gallon Fuel Tank
Speed Control
Moss Green Pearl Coat
All Radio Equipped Vehicles
AM/FM Cassette Radio
4 Speakers
Fixed Long Mast Antenna
Leather Wrapped Steering Wheel
High Pressure Gas Charged Shocks
Tilt Steering Column
Full Size Spare Tire
30X9.50R15LTB Wrangler OWL A/T Tires
Spice Soft Top
Spice Hard Top
15X8.0 "Ravine" Aluminum Wheels
Matching Spare Wheel
All Aluminum Wheels
2 Front Tow Hooks
5 Additional Gallons of Gas
Spring - Left Rear
Spring - Left Front
Spring - Right Rear
Spring - Right Front
FAM: TJ TRACKING: 70204T10AC
FAM: TJ TRACKING: 71212J03
FAM: TJ TRACKING: 80120J13
Customer Preferred Package 2TG
Customer Preferred Package 24G
Customer Preferred Discount
Status D1 to D Less 100%
Paint Order Code


Anything in the list stick out, good or bad to you guys ?
 
#7 ·
Loadedjeep

My guess would be 3.73. Dont worry about getting a ticket. Auto trans and 33's you will not be going anywhere super fast. Your speedo will be approx 5mph slow[/QUOTE]


And if my wife does happen to get a ticket.....who will get the blame and the bill ?

Cheeeep argument insurance....

Thanks to all for the help ! !
 
#8 ·
And if my wife does happen to get a ticket.....who will get the blame and the bill ?

Cheeeep argument insurance....

Thanks to all for the help ! !
LOL that would depend on your state laws. In some states you can go to a shop that still does speedometer calibrations and if found to be off ( assuming it's close to the amount she got the ticket for ) and can be dismissed. But I am definitely not a lawyer and don't know if it will apply in your area.
 
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