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I’m staring down the barrel of a diff rebuild and unless I’m missing something, quality axles are unobtanium. What’s the best route for something that will see 4-5000 street miles per year with less than 350hp. Prioritizing long term wear resistance. I’m thinking about buying this C2 diff just for the axles but I don’t know if that’s the right move. I know they need measured to make sure but to my untrained eye, they don’t appear to be excessively worn. Someone please correct me if I’m wrong or if I’d be nuts to pay $300 for it.
I think your question comes from a conversation we had several weeks ago.
Without writing a book, your options today for axles are
1- New- import, some issues
2- Rebuilt- two styles, QC issues, some are very good, some are bad, it is a spin the wheel type of order today. Depending on the type you get you may have 100% perfect dial in or one that will have to be sent back. One style of axle looks great but is as strong as a straw.
The used diff in the picture is a wide housing, open diff. So, what year is it? Well a check on the casting date and assembly date may help. If you buy it for the axles they have to be checked because what if this is a C3 diff with a 66 open case? Are the axles from a 66 or whatever date code is on the diff? They don't look worn down but are they original to the diff or replacements. If replacements what type? You won't know unless you can inspect them.
As for the value of the housing, as a rebuilder I would not pay more than $200 for that diff since no one wants an open diff. A new posi from Summit is over $830 for an Eaton, knockoffs are less.
I think your question comes from a conversation we had several weeks ago.
Without writing a book, your options today for axles are
1- New- import, some issues
2- Rebuilt- two styles, QC issues, some are very good, some are bad, it is a spin the wheel type of order today. Depending on the type you get you may have 100% perfect dial in or one that will have to be sent back. One style of axle looks great but is as strong as a straw.
The used diff in the picture is a wide housing, open diff. So, what year is it? Well a check on the casting date and assembly date may help. If you buy it for the axles they have to be checked because what if this is a C3 diff with a 66 open case? Are the axles from a 66 or whatever date code is on the diff? They don't look worn down but are they original to the diff or replacements. If replacements what type? You won't know unless you can inspect them.
As for the value of the housing, as a rebuilder I would not pay more than $200 for that diff since no one wants an open diff. A new posi from Summit is over $830 for an Eaton, knockoffs are less.
you are correct. We did discuss this a while back. I thought you also mentioned C2 axles as an option and in one of your other posts a while back you said “An original, hardened GM axle from 63- about 70 will be about the best 17 spline axle you can use today.” But that was 4 years ago. Things may have changed. I’ve been leaning that direction since the other options seem pretty unpredictable.
I have my 72 diff and a 78 I bought to rebuild. I have no interest in the C2 housing or the open diff. Just the axles and maybe the gear set.
The guy has a 64 coupe. Replaced the diff due to the surface rust pitting. Not rebuilt that he’s aware of, so who knows. The pitting on the housing matches the axle yokes but that could just be wishful thinking.
Last edited by dusty1972; Oct 25, 2024 at 06:06 PM.
Good axles. Do they exist?
