Front and Rear Differential Fill Plug Size

[kevindpm61]

My son and I will be attempting to drain the old differential fluid with a suction pump and refilling afterwards. The car is not at my house and I was wondering if the fill plugs require Allen wrenches or some other tool? What size wrench is needed to remove the plugs?

[mudkicker715]

3/8 square. Iirc

[vangremlin]

On my 1980, the front differential requires a 5/8" wrench.  Good luck.

[kevindpm61]

Thanks for the answers gang.

[carnuck]

I plan to reseal the '80 front axle I have with new bearings (I hope) and install it already filled with synthetic oil. They didn't make a drain on the bottom and the fill is hidden behind the engine crossbar.

[kevindpm61]

I plan on removing the plug and using a pump to remove all the old fluids. I bought a hand unit at HF and I'm ready to give it a try.