SS_TOR

Thinking of throwing 3.90 gears in my stock 10 bolt. My car is an M6 01ws6 and pretty much stock except for air lid, adjustable panhard and lcas. It is a true daily driver but with a rotating 12 hr work schedule I only drive in traffic hours 5 times a month. My commute is probably 10 miles city/traffic lights and 15 miles hwy one way.
I was originally thinking 4.10s but thought 3.90s might be a little more durable and maybe i wont have to shift so quickly down low. Do you think its worth it or just a recipe for disaster? I dont really beat on the car since its my DD and commuter. I got 3 points on my license right now so I am trying my best not to drive too crazy lol. Im thinking with avoiding high rpm launches I'd be ok with the stock 10 bolt. Thoughts? Also was thinking of going with motive gears and the motive install kit. Anything else id need?

HCI2000SS

iTrader: (2)

With the way you drive you should be fine

SS_TOR

Ok that's what I was hoping to hear. Forgot to mention this car will see 0 track time. What all do I need. Just the ring and pinon set and ring and pinion installation kit? Anything else I'll need to pick up? Any thoughts on 4.10 vs 3.90s? Is it personal preference? Is there a noticeable difference? Will I be happier leaving a light with 4.10s?

30th t/a

iTrader: (51)

Ive had both in stock 10 bolts. There is only a slight noticeable difference between them. Both are great but I defiantly like the 3:90's better. I noticed that I didnt have to shift "as" much with the 3:90s. Both make a 6 speed ALOT more fun to drive. On the highway you can still cruise at 80mph and only be around 2200rpm. They make 5th & 6 gear more useable.
Get the ring & pinion, a rebuild kit and some rearend gear oil.

AND don't forget to have your PCM recalibrated for the new gears. If you don't, your speedometer will read faster and you odometer will rack up more miles than you actually have on the car....And while your having the PCM recalibrated, have them move the rev limiter up to 6500.

SS_TOR

yea I have a ton of traffic lights to deal with so having to shift less appeals to me. Does the rebuild kit have more parts than the instiallation kit? this is the one I was looking at http://www.summitracing.com/parts/mgr-r75grskt

guppymech

iTrader: (7)

I've come around to the opinion of don't put any money into the 10 bolt, BUT yours is a case of where it would be okay. I initially didn't care for all the shifting 4.10s vs 3.42s but now 3 years later I'd never go back to a 3.42 rear except if I sell the car. IMO the amount of shifting in normal driving is very similar to a Honda with a 5 spd. Skip shifting from say 3rd to 5th is no problem. With either gear set you can forget about hooking up in 1st gear and probably half of second.

SS_TOR

With parts plus labor (since I lack the skill to install myself) how much am I looking at here? Around $500?

FirstYrLS1Z

iTrader: (4)

that kit should contain everything except for a possible different pinion seal. there were 2 designs and you wouldn't know which one you need until it's apart.
$120 for that kit + ring & pinion + labor should be well past $500.

SS_TOR

about how much are we talking here?

FirstYrLS1Z

iTrader: (4)

only the shop doing the work can answer that question.

today I started teardown/cleaning/POR15 of a rearend.
for 6 years I ran the OEM 3.23 rearend,then put a 4.56 rearend in,and now 3 years of the OEM 3.23 rear (after a rebuild) back in. the 4.56 rearend is just sitting there crying to be put back in.
the rear I've started was a 3.42 torsen less axles and backing plates. axles and plates I had. don't know yet if I'm gonna use a Torsen or an Auburn and which gears,3.42,3.73,or 4.10.

z-maro

iTrader: (18)

I would also look into a solid pinion spacer, the revised pinion seal, and possibly a rear diff cover (LPW, T/A, ect.) with the bearing cap supports.

LilJayV10

iTrader: (39)

I just put 3.90's in my 2000 Firehawk and absolutely love them. The car has L/T's, lid and a tune. I'm getting 21-22 mpg highway/city.

HCI2000SS

iTrader: (2)

OP, just to give you an example, i'm still on the stock 10 bolt with mods in sig. My point is...it's all in how you drive it

SS_TOR

Can pinion seals be reused? I had the revised pinion seal put in not to long ago and has helped with it leaking so far.

Majestic9C1

iTrader: (19)

would 3.90's work good in an Auto?? or should I knock it down to 3.73's?

FirstYrLS1Z

iTrader: (4)

any gear will work good with an A4 FOR THE INTENDED PURPOSE.
-4.56s-I ran for 4 years,good light-to-light streetfighter and good 1/8 miler,too much gear for the 1/4.
-4.10s'-max gear for the 1/4 with a stock redline engine.
-3.90s'-5% more torque to the tires than 3.73s'.
-3.73s'-general preferred performance ratio.

BUT a good custom stall convertor should ALWAYS be considered first before a gear mod.

Majestic9C1

iTrader: (19)

I plan on getting either a 3800 or 4000 stall sometime this year..

FirstYrLS1Z

iTrader: (4)

what's you current rear gear ratio ?

Majestic9C1

iTrader: (19)

3.23's

FirstYrLS1Z

iTrader: (4)

seems to me,because you're inquiring about 3.90s' & 4.10s',you're after better acceleration performance. at least you got the 3.23s',which GM opted as a 'performance axle'. but they never offered a performance convertor. cars that went to SLP could get performance convertors but even those were not worth opting for as I think they were B&M 2400s'.
A Yank SS3600/SS4000 or similar from CircleD would really wake up those 3.23s' without changing your freeway mpg like 3.90s/4,10s' would.

gonna send you a PM.