Tag: Identification

Axle Ratio

Find Axle Ratio

There are a few different methods you can use to determine the ratio of your axle, depending on what model of axle you have.  These ideas should help you in determining the ratio of your axle:

The most sure way to determine your ratio is to count the number of teeth on the ring gear and divide it by the number of teeth on the pinion.  For example, if you count 41 teeth on the ring gear and 9 teeth on the pinion, you would divide 41 by 9=4.56.  Your ratio would be 4.56:1.  That means that for every time your axle shaft makes one complete rotation, your driveline will turn 4.56 complete revolutions.

Another method that can be used on a Dana axle, and in most cases will work on other axles, is to get all of the numbers off of the edge of the ring gear.   If you forward those numbers to me, I can look them up and determine what ratio you have.

Also on a Dana axle, if you can find a bill of material number and forward it to me, I can look it up and it will tell me what ratio you have, assuming that there have not been any modifications made to your axle since it was manufactured.

In some cases, there is a metal tag bolted on somewhere around the differential cover.  This tag should have the ratio stamped on it.

If none of these methods work for you, don’t give up hope.  You can always call your local Ford, GM, Jeep, or Chrysler dealer with your vehicle’s VIN number, and they should be able to tell you what ratio you have.  Again, this is assuming that there have not been any modifications made to your axle since it was manufactured.

Attention 4WD Owners:

If by chance you have a 4WD vehicle, and cannot find any information on one of your axles, check the other, as it will be the same ratio.  Remember, this only applies to a 4WD vehicle.

For example, I have had many cases where someone has blown up their rear end to the point where they could not count the number of teeth on the ring gear or pinion, or find any numbers on the ring gear to determine the ratio.  We were able to check the front axle and determine the ratio that way.   This is why ratio is very important in a 4WD vehicle.

I have had people swap out their rear end and not match the ratio in the front with the ratio in the rear.   They drive their vehicle in two wheel drive without any problems, until they shift into 4WD.   When they engage the 4WD and try to drive the vehicle, all heck breaks loose!   Because the front axle is turning at a different speed than the rear, something has to give.  It can be almost anything, transfer case, driveline, ring & pinion, or axle shaft.  Something will break!

Rear Axle Identification

To help you find the right part, we first need to properly identify the axle you have or need. Not all vehicles are set up the same, even though they may be the same make and model.

For example:
A Chevy 1/2 ton pick-up may have a Chevy 10 bolt rear axle or a 12 bolt rear axle. Both of these are semi-floating axles.

A Chevy 3/4 ton pick-up may have a 14 bolt semi-float rear axle or a 14 bolt full-floating axle.

All of these axles take different parts so we need to properly identify the axle you have to get you the right part.

Semi-Floating Axle / Full-Floating Axle

Semi Floating Axle14 Bolt Full-Floating Axle

 

AMC JEEP REAR AXLES

Find your AMC/Jeep vehicle in the chart below and click on the illustration for a larger view.

 

Year
Vehicle
Model
Diagram

1985-1997

Military Jeep, Cherokee/Comanche, Wrangler, Grand Cherokee

Jeep with Dana 35/194

Dana_Model_35_small

 

1977-1997

 

Civilian Jeep, Pickup Truck, Wrangler, Cherokee, Comanche, Grand Cherokee

Jeep with Dana 44

Dana_Model_44_small

 

1978-1988

Civilian Jeep, Pickup Truck

Jeep with Dana 60

Dana_Model_60_small

CHRYSLER / DODGE REAR AXLES

Find your Chrysler/Dodge vehicle in the chart below and click on the illustration for a larger view.

 

Year
Vehicle
Model
Diagram

1986-1995

Dakota

Dodge with 7.25″ Ring Gear

Chrysler_7_25_Ring_Gear_small

 

1971-1997

A&D 100/150, B150/250, Dakota

Dodge with 8.25″ Ring Gear

Chrysler_8_25_Ring_Gear_small

 

1972-1997

Ram Pickup, A, D&W 100/150

Dodge with 9.25″ Ring Gear

Chrysler_9_25_Ring_Gear_small

 

1979-1993

B300, BD600, C300, D200-D700, W200, MB300, MD300, W200HD, Maxivan

Dodge with Dana 60

 

Dana_Model_60_small

 

1979-1993

CB300, CB400, D300-D600, M300-M500, MB400, W300-W400, WM300 & P300

Dodge with Dana 70

Dana_Model_70_small

 

FORD REAR AXLES

Find your Ford vehicle in the chart below and click on the illustration for a larger view.

 

Year

Vehicle

Model

Diagram

1983-1997

Aerostar, Ranger

Ford with 7.5″ Ring Gear

Ford_7_5_Ring_Gear_small

 

1984-1997

Aerostar, Ranger, E&F 150/250, Explorer, Mountaineer, Bronco, Expedition

Ford with 8.8″ Ring Gear

Ford_8_8_Ring_Gear_small

 

1957-1986

All Light Trucks

Ford with 9″ Ring Gear

Ford_9_Ring_Gear_small

 

1985-1997

All Light Trucks

Ford with 10.25″ Ring Gear

Ford_10_25_Ring_Gear_small

 

1985-1989

Aerostar

Ford with Dana 30

Dana_Model_30_small

 

1979

F-100 & F-150

Ford with Dana 44

Dana_Model_44_small

 

1979-1997

E-250 & E-350,

F-250 & F-350

Ford with Dana 60

Dana_Model_60_small

 

1979-1987

E-250 & E-350,

F-250 & F-350

Ford with Dana 61

Dana_Model_60_small

 

1979-1997

E-350(DSO,U-Haul, Motor Home), F-350(Ambulance, 6 Wheeler,

Big Dooley, U-Haul, Dual Wheel)

Ford with Dana 70

Dana_Model_70_small

 

1988-1997

F-350 Super Duty

Ford with Dana 80

Dana_80_Diff_Cover_small

 

 

The Dana Models 60 and 61 look the same and have the same shape differential cover. The most noticeable difference is the reinforced cast iron differential in the Dana 61. The best way to be sure of which axle you have is by the Bill of Material Number stamped on the right hand axle tube. See the Spicer Axle Identification information.

 

GMC / CHEVY REAR AXLES

Find your GMC/Chevy vehicle in the chart below and click on the illustration for a larger view.

 

Year
Vehicle
Model
Diagram

1982-1997

S10

GM with 7.5″ & 7.625″ Ring Gears

GM_10_Bolt_7_5_Ring_Gear_small

 

1985-1997

CK 15/35, S10, RV

GM with 8.5″ Ring Gear

GM_10_Bolt_8_5_Ring_Gear_small

 

1969-1981

CP1, G2

GM with 8.875″ Ring Gear

GM_12_Bolt_8_875_Ring_Gear_small

 

1992-1997

CK15/35, G 10/30

GM with 9.5″ Ring Gear

GM_14_Bolt_9_5_Ring_Gear_small

 

1974-1997

CK35 & G30, V15/35

GM with10.5″ Ring Gear

GM_14_Bolt_10_5_Ring_Gear_small

 

1979-1991

DRW G-Van

GM with Dana 60

Dana_Model_60_small

 

1979-1991

CK 30, R/V30, P 30, P 300,

G 300, G-Van

GM with Dana 70

Dana_Model_70_small