I want to get 4.10 gears, but I've read some stories of people eating up their rear end on a stock 10-bolt. I've also read other posts from people that had no problems. Should I upgrade the Posi? wait untl I can fork over for a 12-bolt? What's recommended?

1993 M6, subframe connectors, other probably irrelevant light mods. Current rear end is from a 90 something (I think it's a 97) Trans Am. After the change, the RPMs are lower on the freeway, so I'd assume it's a lower ratio than my stock setup. I really need to open it up and see what gears are in there.

Thanks in advance!

-Lucas

 

Check this [url=www.f-body.com/gears]gear calculator to figure out what gears you now have in your car. Try ratios such as 2.73, 3.23, or 3.42 to match the speeds to RPM's for your car.

As for upgrading to 4.10's, you don't have to do anything other than buy the 4.10 gear set (ring & pinion). Obviously there are guys who will say "don't waste your money on the 10-bolt", but there are also a lot of guys running the factory 10-bolt still with no troubles (myself included, ***knock on wood***). There are a few things you can do to the 10-bolt to try and make them last longer (aftermarket axles, upgraded posi units, TA girdles) but they'll never be as strong as a 12-bolt or a 9" rear end. However, unless you're making way more power than stock, then the 10-bolt will hold up for quite awhile, and even if you have to replace an axle, or the posi, or the gears, it'll still be cheaper to do than spending ~$2000 on a 12-bolt (unless you starting breaking $h!t on a monthly basis!).

 

When I had my Motive 4.10s put in I upgraded to a Auburn differ.

 

save your money for a better rear end if your stocker is ok. If you have an A4 then your 10bolt may last for a long long time but if you have a 6spd your rear will be toast the first time you hook. The weak link of our stock rears is the 7.5 ring and pinion which can't be upgraded. Also with the 93 6spd you probably don't want 4.10's their overdrive ratios aren't as good as the 94+ 6spds. So you would probably want 3.73's (or 3.90's if you upgrade rear ends).