How do I find my rear axle gear ratio?
Look for a stamp on the differential cover or a sticker on the outside of the housing, and check the code on your driver's door jamb sticker. You can also decode the ratio from your VIN or the axle tag — give us either and we'll confirm it.
Does the gear ratio have to match exactly?
Yes. A mismatched ratio causes driveline bind (on 4WD, front and rear must match) and throws off your speedometer and computer. Match the ratio exactly — a "close" ratio is not a substitute.
How do I tell if I have an open or limited-slip differential?
Your door or axle code identifies it, or you can jack up the rear and spin one wheel: if both wheels turn the same direction it's limited-slip; if the opposite wheel spins backward it's open. Match your original type.
What should I inspect on a used differential before buying?
Check the backlash and the gear-tooth wear pattern, and inspect the fluid for metal shavings. Tight backlash, an even wear pattern, and clean fluid indicate a healthy ring and pinion.
How do I match a used axle assembly to my vehicle?
Give us your VIN or axle code — we confirm the gear ratio, spline count, and brake type so the unit is a direct bolt-in, then text you a photo before you pay.
Related buyer guides
Used engine guide · Used transmission guide · Used transfer case guide · Used ABS module guide · How to find your VIN
Need a differential or axle matched to your vehicle?
Give us your VIN or axle code — we confirm the exact ratio and spline count and back it with a 30-day guarantee.