4.10 gear?

**SLDWS6** · 10-05-2007, 01:21 PM

I am thinking about putting some 4.10s in my 2002 WS.6 M6 car and was wondering what these will do to my gas mileage and what kind of rpms they run at on the highway and such thanks

**JwMonE99** · 10-05-2007, 02:44 PM

I am not sure about RPM numbers but you will loose a little bit gas milage but nothing to worry about.

**2001NBMZ28** · 10-05-2007, 03:36 PM

www.f-body.org/gears/

**grandkodiak** · 10-05-2007, 03:39 PM

4.10's are perfect for m6's, youll still rattle going into 6th, you have plenty of room to go! highway cruise at 1600-2000 in traffic is easy. gas miliage wont be touched, nothing you can notice anyway... that is if you drive the same, but with the gears in the back youll see yourself haulin ass more often cause its that much more fun!!

dont worry about it, get it done, best mod for the money and seat of the pants notice ive done.

play around with the numbers at this site, its dead accurate from waht i see on the road. even with heads, intake, cam, injectors, headers, full exhuast, gears etc. i still get about 17-18mpg highway, and i check every tank to see how im doin.

http://www.f-body.org/gears/

**Mecinoid** · 10-05-2007, 10:38 PM

Originally Posted by grandkodiak

4.10's are perfect for m6's, youll still rattle going into 6th, you have plenty of room to go! highway cruise at 1600-2000 in traffic is easy. gas miliage wont be touched, nothing you can notice anyway... that is if you drive the same, but with the gears in the back youll see yourself haulin ass more often cause its that much more fun!!

dont worry about it, get it done, best mod for the money and seat of the pants notice ive done.

play around with the numbers at this site, its dead accurate from waht i see on the road. even with heads, intake, cam, injectors, headers, full exhuast, gears etc. i still get about 17-18mpg highway, and i check every tank to see how im doin.

http://www.f-body.org/gears/

You only get 17-18mpg. Did the cam and heads drop the mileage the most? I really didn't think it would have made that much of a difference. I know .... if you buy a car like this you shouldn't be worried about mpg ..... But, man I like getting those 29.5mpg numbers on the freeway with my 3.73's and stock tune. When I need performance I reflash it and still get around 27mpg on the freeway if I keep my foot out of it. Do you use your cruise control at all ???? Just not making sense... sorry...

**blackls1ta** · 10-06-2007, 04:22 AM

from 342 to 410 rpm will be 200 more at 65mph

**Too Fast** · 10-06-2007, 04:46 AM

I would like to put in 4.10 gears also. One of my future mods. Along with a needed LS-6 intake. I see by the f-body gears chart that a 4.10 in 6th is barely more RPM than my 2.73 was in OD at 70MPH. So, gas mileage effect not much difference from what I can tell and what others have said.

Biggest negative effect on gas mileage is more radical camshaft.

**roblelp** · 10-06-2007, 09:38 AM

I put 4:10 in my 2000 SS plus alot of other goodies and I get 22 miles per gallion on the highway. They do hum on the highway.

**Mecinoid** · 10-06-2007, 09:59 AM

Let me just add if NOS is a possible upgrade in the future they say the 3.73 gearing is better for you in second WOT and end of 1/4 mile. At least that was the opininon a few years ago when I was re-gearing with my Auburn Pro and 3.73's. I added a girdle and have yet to blow a set of rear gears at the track on drag radials. However, I did twist a transmission input shaft. So, I think my rear gears are strong enough in my set up fyi.

Remember the lower the rear gear you go the less meat you have on the ring gear. In the stock case .... not as good a idea. In a Moser .... aaaahhhhh ..... not an issue.

Let me say.... with 3.73 I'm at 16-1700 @ 65mph and the stock driveshaft would vibrate just a bit on slight thottle in 6th. I upgraded to 3.5 Alum LPE shaft and that went away. CF driveshafts are even better.... But, I think they are about $700.

If I keep her under 70mph in 6th I'm getting at least 28mpg on the flats. Cruise control on of course. It's great for the long ride .... just turn up the tunes and cruise. ;-)

**Jays00ss** · 10-06-2007, 05:15 PM

I have 3.90's in my 10 bolt. They are ok, not much of a gas milage decrease. I just ordered my new 9" yesterday and I got it with 4.30's. Can't wait!!!

**JHayesLS1** · 10-06-2007, 06:10 PM

I have 4.11's in mine. Love it. I'll be at 2000 rpm at 70 mph. I haven't tried test my top speed but I don't see why I couldn't burry the speedo.

**SLDWS6** · 10-07-2007, 03:16 AM

Well thanks alot for the input guys I am hopefully gonna put them in in the next couple of weeks

**Too Fast** · 10-07-2007, 04:16 AM

Make sure you report back!

**grandkodiak** · 10-07-2007, 01:17 PM

just make sure you break them in properly before attmpting to see what they can do. when you put them in make sure you get all new fluid and the slip additive, then be really really kind to them while they mesh and wear into each other properly for atleast 500 miles, then very important, change the fluids AGAIN, it will be chock full of shavings and metallic powder. then you can start gettin on them but change the fluid again 1ce more later on to clean them out good, then they should last you a good while and no longer whine.

id also recommend putting on a reinforced rear end diff cover... aluminums nice and all but find a good solid steel unit to bolt on there, preferably one with a drainage plug on the bottom!! save you lots of headaches later

p.s. MOST rear ends will need an adapter kit and/or mild modifications to properly fit 4.10's, its a small job, think the garage did it for me for less then $50 extra.

**SLDWS6** · 10-07-2007, 07:09 PM

yeah Ill be sure and repost and get them in and let you guys know how I like them. thanks alot

**dlmeadows** · 10-07-2007, 07:38 PM

i have 4.10s and m6 and i still average about 27-28 mpg on highway and average about 22-24 mpg with 70/30 hwy city

**Mecinoid** · 10-07-2007, 10:48 PM

Originally Posted by dlmeadows

i have 4.10s and m6 and i still average about 27-28 mpg on highway and average about 22-24 mpg with 70/30 hwy city

Yeah, this makes sense .... Note he shows improvement around town and slightly lower highway numbers. I'm at 19-20mpg around town ...28-29.5mpg freeway crusin' Actually, we probably spend more time around town so that's probably the better set up. I only went with 3.73's because the NOS.

**dlmeadows** · 10-09-2007, 03:27 AM

Originally Posted by Mecinoid

Yeah, this makes sense .... Note he shows improvement around town and slightly lower highway numbers. I'm at 19-20mpg around town ...28-29.5mpg freeway crusin' Actually, we probably spend more time around town so that's probably the better set up. I only went with 3.73's because the NOS.

well if you noticed i said i average 22-24 mpg with 70/30 hwy city i take the interstate to work everyday and don't drive in the city except for about 30 percent of the time so i can't really give you a good estimate of what mpg i get with city only driving