Inspecting a C5 diff before purchase?
Thread Starter
Melting Slicks
Joined: Sep 2012
Posts: 2,308
Likes: 159
From: LaGrange Park, IL IL
St. Jude Donor '13, '15
Inspecting a C5 diff before purchase?
Long story short. I have a 2004 coupe automatic with 2.73 gears. Might be getting some work done over the winter/spring requiring removal of trans/diff. Local craigslist seller has a 3.42 diff that I am thinking about.
I understand this much from searches...Ideally I want a lower mileage 3 rib setup, if shot peened even better. 3 rib setups came in all 2002 and up, some 2001. Where will it state the "SP"?
Is it simple to remove the cover for pics or inspection to see inside it? What should I be looking for to ensure it is in good condition with no whine or other issues like leaky butt?
I'd be having a corvette specialist shop install, but would like to know I've purchased a good running unit before I purchase.
I understand this much from searches...Ideally I want a lower mileage 3 rib setup, if shot peened even better. 3 rib setups came in all 2002 and up, some 2001. Where will it state the "SP"?
Is it simple to remove the cover for pics or inspection to see inside it? What should I be looking for to ensure it is in good condition with no whine or other issues like leaky butt?
I'd be having a corvette specialist shop install, but would like to know I've purchased a good running unit before I purchase.
Melting Slicks
Joined: Nov 2008
Posts: 2,938
Likes: 65
From: Rochester Hills MI
With the diff disconnected from the trans, there is a small window where you can see the ring gear teeth. There shouldn't be any scratching or scoring on the faces of the teeth. If you have an old transmission output shaft, you can hold the pinion in place to measure backlash and apply gear mesh compound to check the pattern from this window. If you're experienced, you should be able to tell if the backlash is ok just by turning it by hand as well as looking at the teeth without the compound to see how it's wearing. There is a lot more you can check, but you'd have to start disassembling things in order to do so.
With any used C5 diff, you should always replace the Belleville washers inside the differential case. If a washer has broken, the clutch packs are probably scored and will need to be replaced also. This would also be a good time to upgrade output shafts if you plan on making more power. Also remove the left cover and clean the magnet. Be sure to apply the proper sealant to each side cover to prevent leaking.
With any used C5 diff, you should always replace the Belleville washers inside the differential case. If a washer has broken, the clutch packs are probably scored and will need to be replaced also. This would also be a good time to upgrade output shafts if you plan on making more power. Also remove the left cover and clean the magnet. Be sure to apply the proper sealant to each side cover to prevent leaking.
Last edited by SaberD; Oct 9, 2017 at 12:42 PM.
Thread Starter
Melting Slicks
Joined: Sep 2012
Posts: 2,308
Likes: 159
From: LaGrange Park, IL IL
St. Jude Donor '13, '15
With the diff disconnected from the trans, there is a small window where you can see the ring gear teeth. There shouldn't be any scratching or scoring on the faces of the teeth. If you have an old transmission output shaft, you can hold the pinion in place to measure backlash and apply gear mesh compound to check the pattern from this window. If you're experienced, you should be able to tell if the backlash is ok just by turning it by hand as well as looking at the teeth without the compound to see how it's wearing. There is a lot more you can check, but you'd have to start disassembling things in order to do so.
With any used C5 diff, you should always replace the Belleville washers inside the differential case. If a washer has broken, the clutch packs are probably scored and will need to be replaced also. This would also be a good time to upgrade output shafts if you plan on making more power. Also remove the left cover and clean the magnet. Be sure to apply the proper sealant to each side cover to prevent leaking.
With any used C5 diff, you should always replace the Belleville washers inside the differential case. If a washer has broken, the clutch packs are probably scored and will need to be replaced also. This would also be a good time to upgrade output shafts if you plan on making more power. Also remove the left cover and clean the magnet. Be sure to apply the proper sealant to each side cover to prevent leaking.
