SirKnightTG

I'm thinking of getting 4.10 gears (maybe 3.73 I don't know) as I have the stocker 3.31 now. I'm not going to install them myself though. I'll probably take it to the dealer.

I have a few Q's.

1) What oil should be used? Brand & weight? I remember someone talking about Royal Purple for their gears.

2) How does the 4.10 affect the RPMs as opposed to 3.73? I've heard in the city you can gain MPG since it doesn't take as much throttle to get the car up to speed. But on the highway (which I do a lot of) I wonder what the RPMs will be at 70 mph? Not that I'm overly concerned about it, but I'd just like to know for the sake of knowing.

Hufenstang

Hey i actually have 4.10s in my car right now... I cant answer your first question because im not sure. I can tell you that at 80mph im right at 3000 rpm on the highway. I for the life of me cant remember what the are at 70mph right now though. I want to say 2650 but i could tell you for sure tomorrow.

stealth_GT

stay in the slow lane and don't cruise past 60

(-:

that's my plan at least.

06Saleen3V

I have 373s right now and wish i had 410s

TOMBSTANG

I Love mine, they make your car pull stupid hard. I cant imagine not having them anymore.

jahudso2

Here is a spreadsheet that will calculate vehicle speed at certain rpms with your tire size and gear ratio.

stealth_GT

if you have an auto I heard it's supposed to respond like 4.56 gears because of the final drive or something like that lol...
personally I want to see what 4.88 gears can do!~

(O_o)!!

4.6+3650

1. why the dealer? They're going to assrape you. Find a local shop with a lot of gear setting experience. You'll save money and the job will come out better.

2. Our factory fill is a ford synthetic 75w140 I believe, so any full synthetic will be fine. Comes down to your preference.

3. I thought that the 3.73s were the preferred ratio for the automatics?

4. I agree my 4.10s are awesome. Couldn't imagine driving without them.

MeanStang08

Most of the oils come outa the same refinery, just differently labeled.. Lucas, Royal Purple, any of them should work fine.. remember to change it after the first 500 miles on the gears.. 80w140s weight

on my 4.10s that i installed, at 60mph my RPMs only went up around 400rpm best i can tell.. 60mph - 2,100 / 2,200 RPM with the 4.10 gears.. (in 5th gear that is)

Daniel60

I have 4.10 gears and at 2000 rpm is 55 mph. 3000 rpm is 85 mph. Isn't it like 250 more rpms than the what I use to have was 3.55s'. If your running 3.31s then go with 3.73 and have the best of both worlds . city and highway should be just right. Right now with my manual 4.10 are a killer but I wish I could have the 3.73s' at times to give the poor car a break. I can't keep my foot out of it. Can't wait til it gets cooler so I can get better gas mileage.