3.42 gears or 3.73 in a 6 speed car

[gmack221]

hey all I have a bad pinion (bearing spun on the pinion), going to order parts tonight or tomorrow, I had the stock 3.42 ratio gears in the car, happy with the "get up and go", but can't help but wonder what putting 3.73 gears in would do.
questions
1 - how much did this affect your fuel mileage?
2 - what rpm are you running on the highway?
3 - would you change to it again if you had the chance?
4 - do you recomend another ratio for the 6 speed?

thanks and please reply back ASAP

[Mr. Luos]

I run 4.11's with my M6.

Check out this gear calculator.
http://www.f-body.org/gears/
Select 1998 F-Body M6 and it will fill in the tranny gear ratios for each gear.

3.42 at 80 MPH in 6th = 1800 RPM's
3.73 at 80 MPH in 6th = 1950 RPM's
4.10 at 80 MPH in 6th = 2150 RPM's
That is on a 275/40/17 tire.
I still do pretty good on the highway MPG wise. Dropped probably 2-3 MPG.

[98gpking]

Originally Posted by gmack221

hey all I have a bad pinion (bearing spun on the pinion), going to order parts tonight or tomorrow, I had the stock 3.42 ratio gears in the car, happy with the "get up and go", but can't help but wonder what putting 3.73 gears in would do.
questions
1 - how much did this affect your fuel mileage?
2 - what rpm are you running on the highway?
3 - would you change to it again if you had the chance?
4 - do you recomend another ratio for the 6 speed?

thanks and please reply back ASAP

hey man honestly i had a 1996 WS-6 and it came stock with 3:42 as well. i did the same thing as you pretty much messed it all up. so i got 3:73's and i really didnt fee any difference. very little i saw a difference in gas. not so good but id say stick with the 3:42 keep in mind if your running a stock 10 bolt thos rear ends simply SUCK id say save your money for a a 12 bolt and get 4:11's. i mean a stock 10 bolt generaly cant hand slicks. ive heard nothing good about them but my opinion save the gas and stick with the 3:42 youll be just as satisfied

[Mr. Luos]

You do realize how much a upgraded rear end is right??

Not everyone can just afford an entire new rearend.
Gears are an option for stock 10 bolt cars. Just don't run a sticky tire.
You can get away with it on the automatics most of the time though.

[98gpking]

Originally Posted by Mr. Luos

You do realize how much a upgraded rear end is right??

Not everyone can just afford an entire new rearend.
Gears are an option for stock 10 bolt cars. Just don't run a sticky tire.
You can get away with it on the automatics most of the time though.

yea i know how much an upgraded rear end is. its a couple grand but all im saying is if hes gonna be doing some heavy work and wants some good traction. a 10 bolt with a big gear ratio will only dissappoint him,

[Mr. Luos]

I agree 100%.

But maintained, they can hold up decent.
I ran 440 RWHP through mine on the street without problem. Never hooked up though.
Problem is, $2300 isn't always in the budget.

4.10's are the stronger gear set for the 10 bolt.
But this can also increase the stress on the rear end since the car will want to hook better with the more torque.

My best 60' on the 10 bolt (3.42's/nitto DR's) = 2.234
My best 60' on the 9" (4.11's/same Nitto DR's) = 1.868

I am sure some of that was track conditions. I drove roughly the same, but couldn't quite get the Nitto's to hook with the 3.42's.

Wasn't too worried about my rear end. Unless I started pulling 1.8xx short times at the track. Which I never did on the 10 bolt.

[gmack221]

Got my gears today, was going to go with 4.10's, but realized when I went to order them if I went with 4.10's I had to order a seperate $175 piece that goes into the center off the diff to hold the axle shafts out & keep the axle c-clips in place (with a 4.10 the gear hangs so far over the center of the diff the orig piece had to be replaced with a 2 piece part). So I went with 3.73's instead. Have the 6speed out being rebuilt right now, hope the have it all together by the weekend (only time will tell).

[FormulaLT1]

Originally Posted by gmack221

Got my gears today, was going to go with 4.10's, but realized when I went to order them if I went with 4.10's I had to order a seperate $175 piece that goes into the center off the diff to hold the axle shafts out & keep the axle c-clips in place (with a 4.10 the gear hangs so far over the center of the diff the orig piece had to be replaced with a 2 piece part). So I went with 3.73's instead. Have the 6speed out being rebuilt right now, hope the have it all together by the weekend (only time will tell).

Yeah the paddle on the center has to be swapped to fit in those tall gearson torsens. Although they don't tell you that you can grind/machine your current paddle down to make it work and not have to buy that peace but 3.73's are a good gear as well. I think 6 speeds can like with 4.10's and highway speeds though and keep decent fuel economy...

[gmack221]

The rear end is rebuilt now, new gears (3.73's), new bearings all around, new seals. Didn't take the diff case apart but did clean it out as well as I could while it was all together. The pattern looks good, .008 & .009 backlash on the ring gear (gear set calls for .008 to .012), all of the toque to rotates are where they should be, and it now has a vent installed (and siliconed in so it doesn't come up missing again), the housing was painted (have some touch up to do now after the rebuild). Things are starting to come together ... should get my clutch delivered tomorrow, now im just waiting to get the 6 speed back from being rebuilt (upgrades in that are the steel 3-4 shift fork & billet steel 3-4 syncro slides). Should be one smooth operating machine when all of this is completed. Thanks for all the advise, this forum rules!

[DarkblueTA]

Originally Posted by gmack221

hey all I have a bad pinion (bearing spun on the pinion), going to order parts tonight or tomorrow, I had the stock 3.42 ratio gears in the car, happy with the "get up and go", but can't help but wonder what putting 3.73 gears in would do.
questions
1 - how much did this affect your fuel mileage?
2 - what rpm are you running on the highway?
3 - would you change to it again if you had the chance?
4 - do you recomend another ratio for the 6 speed?

thanks and please reply back ASAP

1. didn't affect my mileage
2. 1800rpms @80mph according to the scanner I have with HPTuners.
3. No, not worth the $$$
4. Depends on the plains for your car, n/a, 4.10s...forced induction/nitrous, stay 342

[DarkblueTA]

Originally Posted by Mr. Luos

4.10's are the stronger gear set for the 10 bolt.

Stronger how? strength wise? Don't think so. How is less material(when the gears are the same material) going to be stronger? How many people do you know that sheered off 342s vs 410s. I can tell you 0 - 2 in a 10 bolt.

Now if you mean stronger as in "pulling power" feels faster....sure.