New Differential Questions

[spymaster]

I just found out that my stock differential is going out and will need to be replaced. I was planning on doing this at some point later on, but now it has to be done soon. I am torn between the Auburn and Eaton differentials. I like the advantages Auburn has and I have heard many good things about them, but unlike the Eaton it is not rebuildable. If anyone could give me their opinion, preferrably someone who has used one or the other, it would be greatly appreciated. I know my car is capable of sub-13 seconds runs (dynoed 408hp at flywheel) and I want something that can help me get there consistently and still be a capable daily car. I am also having problems trying to deicide on a ring gear ratio. I have heard that for a 6-speed, which I have and also need to replace , 4.10 are the way to go. Im not too worried about MPG since it already sucks, but I want something that is decent on the highway. Thanks for any information.

[Injuneer]

If you are going to have to buy a new posi unit, and new gears, and then have the entire unit assembled in your stock housing, this might be the time to think about upgrading to a stronger rear axle assembly. Not a cheap upgrade, but if you are going to invest maybe $700-1,000 into the stock unit, it might be worth considering $1,800 to $2,400 for a Moser or Strange 12-bolt. Then you can run on slicks, laugh at 5K clutch dumps, etc.

[Joe 1320]

I agree with Fred here.... an upgraded rear is the ticket. However, if you plan on keeping what you have, the choice of posi is going to depend on the useage. For maximum drag stip traction, the Eaton is tough to beat. It would be hard to wreck that..... the gears are gonna go before you wreck the posi. You will also have to ability to rebuild it if you wear it out. The Eaton unit in my high 10 sec GN is basically stock, has been hammered though over 115K miles of street driving, countless quarter mile runs and still runs strong. Wouldn't change it for anything.

[spymaster]

Unfortunately because the tranny is going out as well, I'm limited to about a grand for the rear end. I have to have some money left over to be able to get the power to the differential.