bubba99

Thinking of changing out my '99 coupe (19k) rear gear. Current 3.42. Looking at 4.10. You guys have the power and experience to talk me into it or out of it. I'm countin' on ya! I'm able to change the unit out myself as I'm only 72 1/2. (I will not waste my time doing the actual gear change. I need the pros to do that.)

Vetteman Jack

jpm995

Depends on your usage. A lot of highway use keep the gears you have. If mostly around town the 3.9 ratio is great. Always feel like you have instant snap when you tap the gas. I have a z06 with 3.9 gears and its perfect. On the highway its good as 5th and 6th are overdrive. Around town its a beast, pulls like mad.

493lszosix

Go for it! 4.10's in my z with m12 trans, love it!

99blkfrc99

b_rad!

No regrets on my 4.10s, makes 6th gear more usable.

Road Runner

Time for a C-5

Thumbs up from a 4.10 owner. 75 mph in 6th is only a little over 2k rpm with factory wheels/tires.

Andrew

Need to know a lot more about the car and what the intended use is before giving advice. Manual, auto, peak hp @ rpm, peak tq @ rpm, redline, tire size, etc... Also, cruiser, drag car, 1/2 mile car, mile car, road course car, etc...

grampi50

Somebody in another thread about gearing changes posted RPM comparisons in various gears at various speeds. It was very helpful. I think for 4.10 gears, the engine only turned like 300 RPM higher in 6th as compared to stock gearing...it didn't increase as much as I thought it would have...

bubba99

Manual, stock. Cruiser. Just want a little more *** around town. Thanks

Road Runner

Andrew

Since you are stock and a cruiser that wants a bit more kick, as some have mentioned, might want to look at a 3.90. Just my .02. The 4.10 is great for a motor that likes to spin high in the rpms.The stock LS1 does not spin high enough to really enjoy a 4.10 ring because you reach redline very quickly in 1st.Driving around town, you may actually feel slower as you will need to let the engine rev 19.9% higher to shift into the next gear to keep the same mph shift points as a 3.42 ring.The 3.73 is a wonderful ring gear, but may not be worth price for the extra 9.06 percent torque multiplier.The 3.90 is the good compromise.Here is another way to think about it. The 3.90 essentially turns your 6 speed transmission into a Z06 6 speed transmission (not perfect but close).The Z’s make a few more HP and torque numbers – even so -go drive a Z and see if that has the right gearing feel for you.If so, the 3.90 would work well and give you similar shift characteristics.If it is too much gear, look at a 3.73.If too little, consider the 4.10.Here is a breakdown. The LS1 and LS6 columns are the stock transmission gear ratios.The 3.73 column is what your 6 speed gears will feel like compared to your 3.42 with a 3.73, etc…You can see that the 3.90 scenario makes your transmission behave like the LS6 transmission as the numbers are similar.Food for thought…Have fun making the decision!

Gear…LS1…LS6…3.73…3.90…4.10

1………2.66..2.97..2.90..3.03..3.19

2……...1.78..2.07..1.94..2.03..2.13

3……….1.30..1.43..1.42..1.48..1.56

4………1.00..1.00..1.09..1.14..1.20

5………0.74..0.84..0.81..0.84..0.89

6………0.50..0.56..0.55..0.57..0.60

acroy

4.1 here. Love it for ripping around town.

4XLR8N

I would go with 4.10s if you are going to the effort and expense of making a change. I researched this quite a bit a few years ago...although I never made the change, there is no doubt in my mind that it would be 4.10s if I ever do..

cv67

4.10 is perfect for a 6 spd its not as low as some make them out to be. You wont feel 3.42 to 3.73.

dork

4.10s in a z06 here. Dunno how I ever tolerated 3.42s... I drove the 3.42s until the clutch gave up at 86,000; 4.10s made a remarkable difference, but it caused MUCH louder engine noise because it's revving higher (in the insulation-sparse z06)-- especially at freeway speeds. RPMs hover between 23-2800 at 70-80mph. That can be a little "tiring" on 10-12 hour drives, especially on the second and third day across the country. The loss in gas mileage is right around the other side of ~20% if that's of any importance. Across "flat" NM and AZ it dropped from 27.4 to 22.9 mpg (80mph).

In the street, 1st gear is almost useless. Ease the gas until ~10-15mph, and a quick shift to 3rd. HOWEVER. The hammer is quick, and powerful, which is the whole purpose of installing lower gears. 5th gear as a passing gear on the freeway is up one level from "perfunctory" compared to the staid EPA-economy OEM 5 & 6th gear ratios, but the same task in 4th gear is "satisfying", especially with a Lwt flywheel, headers and a tune.

All that said about a z06-4.10 combo, I'll probably contradict the tone of my evaluation by suggesting that Andrew has analyzed it very well... 3.90s might be the best in your situation--"stock coupe cruiser around town". 3.73s would be an absolute waste of money.