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33 Pontiac Differential

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Hi Guys, I took the cover off my differential and found a broken outer bearing race and some balls, I think they are from the pinion shaft. I need to get it apart to determine what to do to repair it. Does any one know how to release the axles, I'm guessing this is the next step. I have removed the 2 Bearing caps on either side of the carrier. Any help would be great, thanks, Rick.

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The illustration in the 1934 parts book is not entirely clear but if you have a nut on the end of the axle that holds the hub or hub and drum assembly on you need to remove the hub and drum. After having removed the differential pinion shaft lock screw, push the differential pinion shaft out, remove the differential gear spacer and the two pinion gears you can then push the axles in slightly. This allows you to remove the two horseshoe clips that hold the axle into the differential side gears. Once the axles are out then the side gears are free.

If your broken bearing is from one of the differential side bearings you could then just replace it, set the proper back lash and pattern and reassemble.

If it were my car and I had the differential this far apart I would undo the spring U bolts, the U-joint at the front of the torque tube and take the whole torque tube, carrier and rear axle housing out. Then you could replace the pinion shaft bearings and the side bearings at the same time. Also you could check the gears for damage.

Depending on the mileage it is really poor economy to just replace one bearing because of the labour involved.

My Pontiac has hotchkiss drive rather than a torque tube so it is only about an one hour job to pull my differential carrier. I can lift out my rear floor boards so I don't even have to get under the car. Yours is a lot more labour intensive and I wouldn't want to try it on the side of the road or have to pay a big tow bill because I saved a few dollars.

Up here if your were to remove and replace the complete rear end yourself the local shop would charge you about $800.00 to supply and replace the bearings and set your crown and pinion properly. The four bearing by themselves are about $300.00.

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hi Tinindian, thanks for your advise, I managed to get one axle out, the second is a bit more challenging but it will come, the crown gear has some minor chipped teeth. Do you think that would be OK to use? I like your idea to remove the whole thing and have it professionally set up. Would any differential shop be able to do this? Thanks again, Rick.

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Any differential shop should be able to do that. The current rear end in my car only has half the width of teeth on my pinion. I dropped a ball from the rear pinion bearing and it went through the gears. It did no damage to the crown gear but badly damaged the pinion. At that time I could not find a new or used gearset so my shop ground the chipped and bent parts off the pinion. It gave me 3/4 of an inch of gear rather than 1 1/2 inch. When put back together there was no noise on load or coast. I was told to take it easy and it might last for a while. It has been 5 years and 60,000 miles since and it is still going okay. I havn't run it too hard since (never over 60mph and no higher than a 3500 foot pass. I recently aquired another used carrier and have had it totally rebuilt. It is sitting on the shelf ready when this one packs it in. The 29-32 Pontiacs used an Oakland rear end which was a lot stronger than the original Chevrolet one (26-28) however my ground down one (when it broke) was the third one in 420,000 miles. I gather that the 33-34 differential is much superior.

Good luck with yours

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