2 Tips For Choosing The Right Used Rear End At A Junkyard For Your Car Restoration Project

29 January 2016
 Categories: Automotive, Articles


If you are restoring an older car, you may decide that the vehicle needs a new rear end because the current one has rusted through. You may decide that you want to find a used one at a junkyard. If so, use the following tips to ensure you choose the right one that will work properly with your car's engine and transmission.

Make Sure The Rear End Has The Right Ring And Pinion Gear Ratio

When selecting a used rear end for your car, it is imperative that you choose one that has the proper ring and pinion gear ratio. If the wrong one is selected that has either too many or too few gear teeth, you could throw off your gas mileage. You may also damage your transmission because the vehicle will not be able to shift properly since the RPMs of the motor will be incorrect.

Your car's original owner's manual should have the gear ratio listed in the specifications section. However, if you do not have the manual, you can still determine the ratio by looking at your old ring and pinion gear. Look at the smooth ring below the teeth of the ring to find two numbers, such as 36-10. You can use these to find the proper ratio.

To determine the ring-pinion gear ratio, you can either use an online calculator or divide the ring gear by the pinion gear. For example, if the ring gear is 36 teeth and the pinion gear is 10 teeth, divide 36 by 10 to yield a gear ratio of 3.60. Use this number when determining the ring and pinion gear set size you need.

Once you have the proper gear ratio for your vehicle, ask the junkyard attendant if they have a rear end to match. Once they direct you to a possible part, look at the ring and pinion gear set to make sure the numbers match your car's ratio.

Inspect The Moving Parts For Rust To See If You Can Grease Them

Once you have verified that the used rear end has the proper ring and pinion gear ratio, look carefully at all the moving parts before you decide to buy it. Look at the axles, brake calipers, and joints to make sure they have minimal signs of rust. Try to move them with your fingers as well, making sure they haven't become frozen from corrosion.

If there is surface rust with no metal breakdown, but you can still move the parts, you may still be able to use the rear end if you properly grease it. However, you want to be careful about which type of axle grease you choose to use.

Each type has a different viscosity. If you use a grease that is too thin for the make of your car, you risk having too much friction buildup while you are driving it. This could burn up the gears and axle, causing them to freeze up permanently. This would necessitate another trip to the junkyard for a new rear end.

For example, if you are working on a high-end, foreign vehicle, do not use a domestic grease for the rear end. Many foreign makes have their own special type of grease. If you are unsure of what you should use, you can either consult the owner's manual or ask the junkyard attendant.

By using the tips above, you can increase your success in selecting the right rear end for your car when shopping at a junkyard. However, if you have having trouble finding the correct one, you may want to ask a representative at the business that is knowledgeable in used auto parts. For more information, check out an auto parts shop like Apartsmart.