# Rebuilding the differential



## Guinness (Jun 26, 2016)

I have a number matching 1966 GTO that I have had since 1980, I have had the engine rebuilt (thanks to Butlers Performance), rebuilt the transmission myself, but have never touched the differential, any suggestions on rebuilding or replacing?


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## Pinion head (Jan 3, 2015)

If you drive the vehicle moderately with near stock size tires and wheels, would consider starting with replacing the wheel bearings, if they have not been replaced. Sealed axle bearings are a ticking time bomb, so any times, they seize and chew up the axles. If the original rear is behind a relatively stock drivetrain, the posi still hooks up, and the rear end grease has been changed several times over the course of the GTO's life, the rear may not need much. I can get much more detailed, if you need. Have found the limits of the gray iron Pontiac 8.2 rears, as well as the limits of other performance era rears.


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## Guinness (Jun 26, 2016)

Great suggestion, I have stock tires and spin the wheels every now and then, but nothing serious. I had the back wheel bearing go out many years ago, quite scary, but should probably get them replaced. I have never done any maintenance to the differential, so I am guessing I need to change the oil/grease? If you have a pointer to how to do this I would really appreciate it.


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