4.10?

[JattGunMan]

ok i was wondering if my car had 4.10's some guy i raced said i did...i bought the car used but how can i check???other than takin apart the diff.

[x-40oz-x]

Is your car stock?
Are you the only owner?

The only way it could have 4.10's is if the owner before you put them in and the only way to check is to take the diff cover off.

Chances are the guy you raced is an idiot.

[chrisg]

Yeah I think the only way to check is to pull off the cover.

[1959ls1]

I might be full of shit, but if you count the number of rotations the drive shaft spins for 1 complete rear tire rotation it should tell you what gears you have. If it only spins 3.5 times you got 3.42s, 3.75 times 3.73, and 4 times you got 4.10 or 4.11s, and so on and so forth. I could be wrong though, wouldnt be the first time, just ask my wife.

[t/as&dds]

I might be full of shit, but if you count the number of rotations the drive shaft spins for 1 complete rear tire rotation it should tell you what gears you have. If it only spins 3.5 times you got 3.42s, 3.75 times 3.73, and 4 times you got 4.10 or 4.11s, and so on and so forth. I could be wrong though, wouldnt be the first time, just ask my wife.

He's right. Don't pull the diff cover off, just jack up the rear and mark the driveshaft and spin one of the tires. It's a pain in the sack to pull the diff cover just for that.

[x-40oz-x]

But if his tires aren't stock it won't be accurate will it?

[tonyjnjz]

um isnt there an even easier more obvious way to tell the diff between 4.10 and 3.42's .....do 60mph in 6th......whats your rpms??? will be at least a few hundred higher with 4.10s...belive mine is around 15 or 1600 with the 3.42s .....so maybe 2k if u have 4.10s??? check it out...if its around 15 or 16 yours are stock.......

[mrr23]

it would be better to drive in 4th (manual) or 3rd (auto) for a 1:1 ratio through the transmission. then, use this formula to figure it out.

RPM = MPH * GR * 336 / TD

RPM = RPM
MPH = MPH
GR = gear ratio
336 = magic number to make formula work
TD = tire diameter

based on 60 mph
3.23 = 2533
3.42 = 2682
3.73 = 2925
4.10 = 3216

with an auto, the rpms will be slightly higher, if converter is unlocked.

[2001NBMZ28]

You can also try a calculator like www.f-body.org/gears/

[JattGunMan]

thanks for all the replys but i tried using the formula and i couldnt figure it out...i went to 60 mph in 4th and i was at 2800 rpm....and the tire diameter is around 25-26?i hope thats td(275/40/17)...my rpm came out to like 2542531....what am i doing wrong?thanks

[mrr23]

did you do 3.42 or 342? looks like you are missing a decimal. also, i assuming you have a manual trans.

[JattGunMan]

i tried all the gr's and 3.42 with the decimal seems like the closest to 2800spm at 60 it came out to 2757.888 so im assuming i have 3.42 and it a m6..what did these cars come wit stock?01 camaro ss

[mrr23]

3.42 is stock for m6 cars. look on the RPO sheet located in the driver's door jamb. it should have a code of GU5.

diameter is 25.7 for your tire. that should fix your formula.

[JattGunMan]

crap haha i was hoping for 4.10's...o well looks like i have something to look forward in getting..which is always fun..thanks alot for all the replies your formula is awesome man

[NinerSevenTango]

Counting the revs on the driveshaft is the easiest way to tell. You have to jack up both rear wheels. If the wheels don't turn together, then lower one of them, and the remaining wheel will turn double the number of revolutions. It doesn't matter the size of tire, the gears inside the housing don't care. For accuracy, you might want to count multiple revolutions and then divide it out. It's awful hard to tell on just one revolution of the driveshaft because you are splitting hairs on the accuracy of your one revolution. Finding a buddy that can count will lower the frustration level.


You can't go by the RPM/speed because the speedometer uses the calibration in the PCM. If someone changed the rear end ratio, did they put the proper multiplier in the PCM? And this multiplier does rely on tire diameter to make the speedometer read correctly. It will only read out what it is programmed to read out on the speedometer. It won't tell you what rear end you have. And it won't be accurate unless it is set up for both the proper gear ratio and the proper tire diameter.

--97T--