12 bolt 4 series carrier question
 

Hello all, Does anyone know specifically what to look for on the 4 series carrier to determine if it is a COPO carrier vs the standard one? The carrier has black marker writing that says "r/b Moroso" which I assume means rebuilt by Moroso. The gears are 17-10 and new, the clutches are new and the unit does not look like it was run after the suspected rebuild. The carrier is dated C 13 J (Mar 13th 1969). With the parts is a box of 12 bolt posi carrier gears that are 16-10 and identified as COPO gears, do not know if they came from this carrier or not. Any help would be appreciated to determine if the carrier is a COPO unit or not. Thanks Andy

Attached a few pics for reference.

Trying to find this thread..

thanks, i have seen it and several others. I was hoping someone had pics of the copo case differences since most threads dont have any pics. Based on what i have found I thought this might be the best place to locate some pics that might define the specific differences. take care, Andy

With those heavy springs it looks to me like a Moroso Brute Strength posi unit, are there any part numbers stamped on the outside of the flange?

The heavy springs had me thinking it was a Moroso unit, I checked the gears and the clutches, it is 17-10 but the clutch count is 18 total the standard for the 4 series not like the brute strength unit which has 22 total. the only stamped numbers on the unit are the date C 13 J . There are COPO carrier gears 16-10 with the parts i got but i do not know if they would work in this unit or not since a COPO carrier is machined differently. I am trying to see if i can confirm if it is just a standard 4 series or a COPO one. I am beginning to think it is a standard unit rebuilt by moroso back in the day and never used. I was hoping someone here might be able to proide an example to compare to. thanks Andy

You can try and install the COPO gears and see if they fit. If it is not a COPO carrier and you install the side gears, you can't get the spider gears in with the stock clutch count.

Some info: http://www.camaros.org/carriers.shtml

posi
 

is there anyway to identify that a posi is copo other than take it apart and count the gears. Here are some photos of one I have in a rearend. Appears to be 8 teeth showing on the spider gear but its hard to tell. The window openings look like the previous post. What are your thoughts. Thanks, Larry

A round hole in the stamped steel spring plates is another indicator.

Most 4 series cases have the small square hole. I've seen a few with the larger oval hole. but not many. All Eaton gear sets have 10 teeth on the pinion gears. They are 18-10, 17-10 and 16-10. Standard units from Chevy are 18-10. Eaton made a heavy duty unit that was also sold by Moroso that had 17-10 gears and the COPO units had 16-10 gears. New Eaton units have 17-10 gears that are made from powdered metal.

Your preload plates look like they have oval holes in them, which would not be in a COPO unit.