C2 - Differential/Side Yokes

[Rory Riedy]

At a point in my 66 BB restoration process where my attention is focused on the rear suspension/differential area. Noticed that I have one standard duty (U-bolt type)& one heavy duty (threaded cap type) side yoke. How would I know which is the correct side yoke type for my application? The differiantial is a 3.70 rear end.

Also since I am not sure of the internal condition of the differential, I am thinking of having it rebuilt. What are the pro's & con's of a rebuild job?

Would like to hear (good & bad) from those that choose the rebuild route. Who would you recommend to do the rebuild? Is there anyone I should stay away from?

As always I am sure I can count on the vast experience of this membership to guide this novice along.

Thanks,

Triple R
#42670

[Duke W.]

Re: C2 - Differential/Side Yokes

All BBs were originally equipped with the cap type side yokes, so obviously one of yours has been replaced, which requires opening up the axle.

Axles are generally long-lived components, but their life can be shortened considerably with hard driving. Whether to overhaul or not depends on its current condition and how you plan on driving the car.

Was it noisy or leaking before it was removed? What is the measured Positraction preload? What is the side yoke end play?

If the above are not well within spec, open up the axle for a visual inspection and some checks - differential gear backlash, ring and pinion backlash and tooth contact pattern. If you do open it up, as a minimum I would recommend replacing the all the seals.

A complete overhaul assuming the ring and pinion are reused usually requires a new or rebuilt Postraction carrier, bearings and seals, and will probably cost in the neighborhood of at least several hundred dollars, however, complete Eaton replacement Postraction cases are on backorder now, but Auburns are available.

If a new ring and pinion is required, the price will increase due to both the new parts and additional set-up time.

Axle assembly is a precison job, so if you do have it overhauled, only consign the job to a specialist with experience and a proven track record setting up Corvette axles.

Your CSM and COM will give you and idea of what's required.

Duke

[Duke W.]

Re: C2 - Differential/Side Yokes

All BBs were originally equipped with the cap type side yokes, so obviously one of yours has been replaced, which requires opening up the axle.

Axles are generally long-lived components, but their life can be shortened considerably with hard driving. Whether to overhaul or not depends on its current condition and how you plan on driving the car.

Was it noisy or leaking before it was removed? What is the measured Positraction preload? What is the side yoke end play?

If the above are not well within spec, open up the axle for a visual inspection and some checks - differential gear backlash, ring and pinion backlash and tooth contact pattern. If you do open it up, as a minimum I would recommend replacing the all the seals.

A complete overhaul assuming the ring and pinion are reused usually requires a new or rebuilt Postraction carrier, bearings and seals, and will probably cost in the neighborhood of at least several hundred dollars, however, complete Eaton replacement Postraction cases are on backorder now, but Auburns are available.

If a new ring and pinion is required, the price will increase due to both the new parts and additional set-up time.

Axle assembly is a precison job, so if you do have it overhauled, only consign the job to a specialist with experience and a proven track record setting up Corvette axles.

Your CSM and COM will give you and idea of what's required.

Duke