part 2 of this:
http://forums.corvetteforum.com/c5-t...-a-clutch.html

my differential is in bad shape. it was making unusual noises a while back, a fluid change made it go away. a year later the problem is back and not going away again. I took it to be looked at and there's a rebuild in my future. the car is still drivable, the shop said isn't not about to puke parts or anything, but it needs to be rebuilt to fix the sound and not-smooth sensation in right turns.

so considering alternatives, I think I might like to change my rear end ratio at the same time. if I have to spend $2000+ to fix a problem, I might as well get faster at the same time.

the car is a 6 speed, stock 3:42 in it now.
I have not tracked the car before, but I'm getting closer and closer to wanting to, it will be drag racing only. but I also daily drive it. doing the math on the ratios it doesn't really look like something as high as 4:10 will really be a problem for daily driving. I'll probably end up one gear higher than I usually drive now, and see rpms a couple hundred lower. My commute is short, so I usually drive at 2000rpm, 2nd at 25, 3rd at 35, 4th at 45, 5th at 55. seems easy enough to live with. I'm not very concerned about MPG, but I don't expect to see a huge decrease there either.
looking for advice on a few things.
new clutch packs, C6Z output shafts (they are a weak link in the drivetrain I believe, car makes ~355-370whp/tq) new seals, there is evidence of past leakage. and hopefully new gears. anything I'm missing?
a shop quoted me $1000 for the rebuild, but he started questioning whether it was an easy swap to put C6Z shafts in it. with about $500 of that for the R&R labor, it makes me think I might be best off to buy a built diff from a company that really knows their stuff and just have them install it.
I've looked at DTE and RPM, any others I should look at?
does anyone else daily drive with higher rear end gears?
I like to make my cars faster. but a car that can't be daily driven to work every day the ground isn't white, or not able to be driven comfortably for 10+ hours on the highway is no use to me.
looking for help, advice, an opinions! I'll probably be having this done in the spring.

 

DTE, RPM, RKT are all good places to talk to. If you need a new diff, new gears, and race prepped internals (shafts, clutch springs, micro-polished gears etc.), I would suggest buying a complete stage two diff and send yours in as a core.
I have a stage two diff on the way from RPM as we speak. My 3.42 diff is good for a $750 core change if I remember correctly.
The stage two is plenty strong enough for a street car and can handle upwards of 600 whp without worry. I think it would be a good choice for you as a replacement/upgrade.
3.90's would be an excellent daily driver gear and a kick up for some drag racing IMO.

 

Talk to Rick at RKT56. He is a sponsor and an active member here. That's all he does.

 

Rick built A Level 4 M12 tranny and 3.42 diff for me last year sing all the good guy C6Z06 stuff. I got a wild hair a month ago and had him swap out the 3.42 to a micro polished 3.90 ring and pinion two weeks ago. I just finished the 500 mile break in today. I ran 3.90's in my 346 and 403 builds and I think the cars should have come from GM with them. In the 427 it's gone past stupid all the way to ridiculous but it does give me a better gear at certain MPH and makes 6th gear more useful.

Top quality product and customer service!

 

I also agree - Talk to Rick at RKT56. If you want to buy a new GM diff talk to Gene Culley at gmpartshouse.com Gene will give you a good price on new GM parts.

 

Thanks guys!

To the OP, if you have a coupe/vert 3.90's would be best all around. If you have a Z06, I would recommend 3.73 for DD. We can build your diff or have one built to your specs and take yours as a core. Please contact us to discuss in detail.

 

Thanks for the info! its great when so many chime in with the same advice :-)

Rick, so the details of what I'm looking for are in the opening post. It sounds like 3.90 would be good for me. It's a 99 coupe. Would you mind PMing me with some details and pricing?

thanks!

 

PM sent.