C2/c3 axel shafts

[Jim B.]

I have four axel shafts that appear to be the same except for the diameter for one pair is approximately 3/4" bigger than the smaller ones. I can't find any numbers so is there a way to confirm the years they were made and are the larger ones usable on a non-matching number C2? Thanks, jb

[Gary R.]

Re: C2/c3 axel shafts

Jim. Are you referring to the 1/2 shafts or the differential inner axles? The 1/2 shafts should be the same for 63-79 to my knowledge, the diameter did change in '75 (2.5" to 3")but the length and joint size(1350) were the same. Some of the aftermarket shaft were made wrong and resulted in positive camber a few years ago, I think that was addressed though. Many think the 2.5's are weak and buy 3" or new aftermarket but they were strong enough and had a thicker wall tubing then the new ones on the market do.

[Joe L.]

Re: C2/c3 axel shafts

I have four axel shafts that appear to be the same except for the diameter for one pair is approximately 3/4" bigger than the smaller ones. I can't find any numbers so is there a way to confirm the years they were made and are the larger ones usable on a non-matching number C2? Thanks, jb

Jim------


It's a Gary describes. The 2-1/2" half shafts were used from 1963-74. The 3" half shafts were used from 1975-82. The half shafts can be used interchangeably. In fact, the 3" half shafts became SERVICE for 63-74 after about 1976.

I believe the 2-1/2" half shafts were of GM internal manufacture. The 3" half shafts were manufactured by Spicer.

[Jim B.]

Re: C2/c3 axel shafts

Gary and Joe, Thanks so much for your responses as I just got back a spare differential that I had rebuilt and will include all new u-joints with the installation on my '63. Since the larger 1/2 shafts will interchange, I can put the new u-joints in those first as they are also spares. I thought they would fit but appreciate your confirmation before I installed the new parts. Do you recommend any particular u-joint removal tool as these are older and more challenging than any I've swapped before? Thanks again

[Gary R.]

Re: C2/c3 axel shafts

Gary and Joe, Thanks so much for your responses as I just got back a spare differential that I had rebuilt and will include all new u-joints with the installation on my '63. Since the larger 1/2 shafts will interchange, I can put the new u-joints in those first as they are also spares. I thought they would fit but appreciate your confirmation before I installed the new parts. Do you recommend any particular u-joint removal tool as these are older and more challenging than any I've swapped before? Thanks again

Jim, you can read my thread on u-joints, it is on Digital corvettes, if you can't find it let me know and I'll get you the link. I use a torch to burn out the old joints, then I blast and prep them. I use only Solid Spicer joints, these are larger in the cross size then the originals but I feel they are the best on the market. I made a simple 3/4" steel plate to bolt the flange to so they don't get bent. Look over your shafts for dings or dents in them by the yokes, that would be from a previous rebuilder crushing them in a vise. If you use the spicers then you will have radius the yoke a little bit to allow them to be installed. I get the joints installed almost all the way and then only use a press to final seat them and install the clips. There is a good chance the flanges are bent again from previous work, if so you may be able bend them back- there was a article about this in the restorer a few years ago. Typically when I find a bent flange I replace it. Spicer still makes them as does the aftermarket. The only time I had a solid spicer fail was in my son's 75 st/strip vette and he sheared the joints clean off launching the car at 4000 RPM with 400+hp at the wheels. If it wasn't for the fact I build him a 12 bolt IRS he would have probably split the posi in 1/2 before the joints sheared. So unless you are in that category you will be just fine.