Welcome to the Corvette Forum Nick.Faga! This is the best place to be if you have any questions about our favorite sports car!

Just so you are aware, GTR1999 is an expert in this field or Corvette Differentials!

If it takes him 35-40 hours of work to rebuild a Corvette Differential I would certainly not expect your First differential to go faster than a leading Expert can do the job. I always give myself extra time when doing something new. I heard some clicking from my differential when turning and the extra Posi additive did not change anything so I had my differential rebuilt by a Chevrolet Dealership I was buddy's with. It has lasted over 33 years for me since then and it works flawlessly.

So you are going to all that work for a tiny gear change? I have a 3.36 with my L88 clone engine and I can pull 10 second quarter miles and still go from 0-60 in way less than 4 seconds. If anything I would go lower trying to get some traction. The car will burn it's tires past the 1/8th mile mark at a 1/4 mile strip. I have outran a 600cc four banger hyper bikes. I love playing with 911's....

No, actually I have "grown up" since then and I don't do that anymore. After the motorcycle incident I had a visit from our local Hero LEO's who suggested I not pass a Police Station at speeds like we were traveling that day.

The "Beauty of this Forum" is that we are able to get help from dozens of folks with lots of experience with the Corvettes that offer you free help with your C3 issue. When you hear from a member like GTR1999 and he offers free advice to you take it and say "thank you". I personally would gladly pay for GTR1999 for any advice if I had to do anything to my differential, he is worth every penny. There are a lot of people who know so much about the C3's on this forum and they all help out of the goodness of their hearts.

I come here to "learn" and occasionally I will respond if I have anything to offer. I have had my C3 since 1991 and my C4 since 1999. I have had to learn a good deal about Corvettes since then.

I feel it is good to "share" so others don't have to pay the prices I have paid. Shared knowledge is a Great thing!

Nick.Faga, We are Glad that you have joined us here at The Corvette Forum. Even with more than 50 years of Corvette experience I still learn new things regularly here!

 

I appreciate the amazing welcomes and all of this great information everyone is giving me. I wouldn’t know what to do about my failing differential without you guys. I would’ve taken it to a shop and been charged for labor. I will definitely say I figured out I was looking at the wrong parts pretty quickly. I am 18 and still learning about automotive so I want to learn how to do everything on this car and how to do it right. I’m very lucky that 3 of the senior master techs that I work with offered to help me so that’s why I was expecting a quicker job. My plan is to take however much time I need to gather the right parts and build the new differential aswell as get some supporting parts like u joints and bushings or whatever else I find upon another few inspections. Once I build the new differential outside I’d the car I want to swap out the old and put in the new one and rebuild my old one as a backup.I was thinking about the 3.70 or 3.73 just because I thought it would make it feel more peppy. now that I’m also thinking ab the fact that I don’t want much tire spin, but then again I’m not really going to be driving it real hard, anyways I am still deciding what gearing I want and I am fine with getting a different case if you guys recommend. I currently have a case from another c3 it is an 8.2 I haven’t ordered gears or anything yet so I’m open to suggestions. I have a lot of work to do and a big plan for the vette in the works. Again thank you all for the advice.

 

C2 and C3 differentials are not called 8.2 or any type of number.number. So unless you check the date code and gear code and actually count input revolutions versus output or count gear teeth, nobody here knows what you have.

 

I don’t know what I have either and that is why I’m trying to ask. I have a case with nothing inside. I have an oem 1978 corvette differential case with nothing inside laying around at the moment. I would just like help with recommendations if I would get a different case or consider different gears and what gears am I going to go with since I was thinking about changing the gearing.

 

I spun the tire one full rotation and the driveshaft spun 3 and a half times. So Ik that I currently have a 3.55

 

all most perfect for an OD trans

 

I have a rear main seal leak so I gotta drop the trans soon anyways… sooooo. I may have to.

 

all I can say is,
do all you can now and enjoy later

 

Can you post pictures of what you have?

 

got it. I’m saving up and learning everything I can right now.i have sum cool cosmetic plans but that’s not happening for a while so im not worried about that. Definitely focused on making this my own masterpiece.

 

this is all that I have for the new differential so far. If I should get a different housing let me know please.

 

If you want a mass production assembled carrier, here you go
Edit, corrected link
Carrier Assembly

 

Mel, I assume you were referencing Summit for the Eaton and not that particular one, since it won't fit a vette. Most likely a typo, but that is a 12 bolt 3 series with 30 spline spiders.

 

Of all the days for me to make that mistake! Totally embarrassed. I attended a tech seminar today covering many things including differentials given by Gary R.

 

You should have reached out last week because I held a tech seminar today in CT that would have been worth your time to come to. You would have gotten more information than most vendors know, and certainly more than common techs will know.

I read where you are intent on building your own diff with your friends help and that's fine. Only one way to learn is to do.

This will be my only comment, and I may check back from time to time.

Your pictures tell a story if you know how to read it. You don't show the bearing caps, if they are with it or not. The story on that Carrier is not complete unless you show the caps and internal of the Carrier. That is a 63 Carrier as GM called them. Looks like July 10, 1963. The case holds the ring gear and clutches- posi case.

 

Don't be, there is more to that carrier in the picture that some may not see or know.

 

As Gary pointed out, that is a 1963 case. Stay away from that one. Find a 3899143.

 

Thats great to know thank you I will send more pics of what I have tomorrow morning anyways

 

here’s some more photos I was curious about that damage in the 3rd and 4th photos aswell would that have an effect if the case were to be used

 

Do you have the original bearing caps? If not you need a different case, that one is worthless. In addition you should be looking for the other number case.