How to Replace Rear Differential Fill Plug

If your differential is leaking from the fill plug, or if the plug's square indentation is rounded out, you'll need to replace it. Whether you're buying a new plug or just reusing the old one after refilling the differential, it's just a few easy steps to seal the system back up.

Instructions

1




Locate the fill plug. Most cars will have the small circular metal plug on the side or the front of the differential, about halfway up the housing. Chryslers and some other makes may have a rubber plug on the differential cover itself.

2

Place a catch pan underneath the plug to catch any fluid drips, and prevent staining the garage floor--or staining you! (If you have the car up on two jack stands, the car's not level and you're more likely to have some spilling.)

3




Remove the plug using a 3/8 inch drive ratchet with extension. (A few models may require a hex key or screwdriver, but the 3/8 inch is the most common plug design.)

4

If you'll be reusing the old plug, clean it off first. You can usually just rub it vigorously with a shop rag, but for stubborn grime try a dash of brake cleaner. Be sure to clean the magnet at the center of the plug so it can adhere more easily.

5

For extra security, add medium strength lock tight (blue) to the threads. Replace the plug and tighten with the ratchet. Make it a snug fit, but there's no need to over tighten.