Rear gears

[Chancey]

I am definitely going to go ahead with changing my gear ratio from the factory 3.31’s. I am almost decided on going with the 3.73’s. I really love aggressive launches. I do not care about top end speed. I dont really care about mileage either. I went with the Nitto NT555R 305/35/20’s and it hooks up SO much better. I will never see a drag strip, only hard street driving and its my daily.
My question is this: should I go with 3.73’s or 4:11’s? Which are most guys running? Thanks for any input.

 

[StrayBullitt]

Gear it till ya Fear it !

 

[Cman01]

Most guys will say 4:10's. I would kinda agree but for my use when I do road courses 4:10's would be too steep so I had done 3:90's for like 1 month and a bit last year. That gear was calculated to be the perfect gear for my use of both RC and Drag strip.

I ultimately changed it out to FRPP 3:73 due to gear noise from the fully polished US Gear 3:90, and now my gear is quiet.

Do a search, the whole debacle with the 3:90's are posted up from last year.

Tony

 

[Chancey]

Most guys will say 4:10's. I would kinda agree but for my use when I do road courses 4:10's would be too steep so I had done 3:90's for like 1 month and a bit last year. That gear was calculated to be the perfect gear for my use of both RC and Drag strip.

I ultimately changed it out to FRPP 3:73 due to gear noise from the fully polished US Gear 3:90, and now my gear is quiet.

Do a search, the whole debacle with the 3:90's are posted up from last year.

Tony

Thanks Cman01.

 

[Handlebar Moustache]

I have 4.10s and find it to be well suited for me...the 6th gear in the TR6060 gives you plenty of overdrive. IIRC I'm at ~1800 RPM at 70 mph in 6th. I like that the clutch gets beat up less with the lower gears. All that said, I can't hook up in 1st or 2nd...but I don't think I'd be able to with 3.31s either.

 

[Chancey]

I have 4.10s and find it to be well suited for me...the 6th gear in the TR6060 gives you plenty of overdrive. IIRC I'm at ~1800 RPM at 70 mph in 6th. I like that the clutch gets beat up less with the lower gears. All that said, I can't hook up in 1st or 2nd...but I don't think I'd be able to with 3.31s either.

Thanks man. Im so torn between 3.73 and 4.10’s.

 

[1 Alibi 2]

3.73's, thought 4.10's for my needs would be overkill.
The gears were replaced before the car had 700 miles on it..

 

[Catmonkey]

Thanks man. Im so torn between 3.73 and 4.10’s.

Just because one person had a bad experience with 3.90s, I wouldn't rule them out and it splits the difference between those ratios. I'm running a 2013 transmission in my 2012 and I have 3.73 gears. I also have a moderate camshaft that would be happier with 4.10s for in town driving. Regardless which ratio you choose, you will need a tuner to change the ratio to recalibrate the speedometer. The factory tune has a limit that can't be exceeded by the dealer's tools for the rear ratio.

 

[72MachOne99GT]

I have about 300 hundred miles on my 4.10 rear and about 100 of those on the Nitto555Rs. While I don’t have as much seat time as I’d like, I can also assure you that the time I do have has been very rewarding.

 

[biminiLX]

As long as you’re willing to run DRs no reason to not run 4.10s
It makes the car so much better everywhere out of boost, doesn’t hurt highway driving (actually helps 6th) and puts you much more optimal on the drag strip. Unless you’re a road course or standing mike guy, gears are the best mod after tires.

I have about 300 hundred miles on my 4.10 rear and about 100 of those on the Nitto555Rs. While I don’t have as much seat time as I’d like, I can also assure you that the time I do have has been very rewarding.

Good choice! I keep telling people not to fear the gear. Now that you’ve driven the 4.10/DR combo do you have any reason to think 3.73s would be better?
-J

 

[Cman01]

Just because one person had a bad experience with 3.90s, I wouldn't rule them out and it splits the difference between those ratios. I'm running a 2013 transmission in my 2012 and I have 3.73 gears. I also have a moderate camshaft that would be happier with 4.10s for in town driving. Regardless which ratio you choose, you will need a tuner to change the ratio to recalibrate the speedometer. The factory tune has a limit that can't be exceeded by the dealer's tools for the rear ratio.

The problem is not too many gear manufacturers make that ratio. I wish FRPP came out with 3:90's (I think at 1 time they did many years ago and stopped providing them, and because of my experience with them I think I know why).

I spent a ton of money getting US Gears "new" at the time ISF coated gear set (advertised as THE BEST gearset made), had it sitting in my closet for well over a year then when I got it in (installed at a very qualified and reputable shop) they were noisy right from the get go. An adjustment was made no charge (but I had to take a day off to drive the car there to the other side of town from where I lived) and it was still noisy.

After waiting weeks and numerous emails/phone calls back and forth between me, US Gear and the shop owner I just said F it had the shop order in for me FRPP 3:73's, installed and viola...…………..no more gear noise. I then had to wait a few more weeks to return the bum gearset to US Gear to get back my cost of the gearset (minus shipping) but I was out the price of another install of the FRPP gears (the shop owner did cut me a break on the cost of the second install).

I was happy to at least get back most of my cost of that gearset (I'm sure most other places would've told me to take a hike especially having the part for well over a year before install), but I had bought what I thought at the time was the best gearset avail for my Shelby, the gearset I REALLY wanted in my car and the whole thing turned out to be a dud.

 

[Catmonkey]

Ford had a 3.90 gear set for the 9", which was a fairly popular ratio on the 60-70s muscle cars. I don't think they ever made one for the 8.8. On the other hand, I don't believe Ford offered a 3.73 gear set in a production vehicle for the 9" either. They're only 5% different, which is hardly enough difference to justify replacing one for the other. But for someone that thinks 4.1 is too much and 3.73 is not enough, it is between those ratios. I hear lots of complaints over 3.73 gears whining on these cars. I just don't think 4.10s are too much gear unless you're running a rear tire diameter less than 27". But they would be a bit much with the 2.97 first gear on the 07-12 transmission.

 

[Cman01]

That's the thing, the jump from 3:31's to 3:73's wasn't enough of a jump for me to spend the money on a gear install. I knew 4:10's for me and my use was going to be too much so why I originally wanted 3:90's. On paper, it was enough of a jump in gear ratio to justify the cost to do but not too much of a jump where it would cause an issue with me running Mosport with my car.

So when my 3:90 ended up being a dud and I had to go 3:73's, I was a bit ticked. All that planning, calculating and wanting my 3:90's only having to do 3:73's because of noise I should've just left my 3:31's in there.

If the crystal ball told me not to do 3:90's because of noise I wouldn't have bothered with a gear swap.

 

[Catmonkey]

Hindsight being what it is, do you wish you had gone 4.10, or are you happy with the 3.73s?

 

[Cman01]

I still would like a 3:90 in my car but for now I'm happy with the 3:73's.

 

[Chancey]

Now Im leaning towards 4.10’s. Seems like with the hard launches I want and the transmission gear ratio’s like they are in the 2013 even though its a daily, I would best settle on the 4.10’s.

 

[fearthesnake]

Hindsight being what it is, do you wish you had gone 4.10, or are you happy with the 3.73s?

I went with the 3.73s and no regrets here. Noisy gear though but bearable.

Friend of mine got tired of the noise on his 3.73s and bought a low miles 2012 entire rear end with 3.55s and dropped in his. Quiet and to his liking.

 

[Jam421]

I had FRPP 3.73's that whined like crazy after the first hit just past the 500 mile break in. Soon after I went to 4.10's. I am running taller MT ET's at 21 psi which make the ratio closer to 3.90's. After an upper pulley, headers. 680/678rw a shop convinced me to swap in 3.73's. Three weeks later I'm already hearing the 3.73 whine building around 2200rpm local cruising. I called the shop and went back to the 4.10's ->) !!! Crazy heh?
In my experience both gears are the same out of the hole on the street...either gear got to pedal at 1/2-3/4 throttle with TC on. But from a 10-20mph roll 2nd gear on a WOT stab the 4.10's dead hooked and were way more explosive than 3.73's all thru the gears. Also....much 4.10 fun was entering a highway in 3rd.....the instant boost with very powerful acceleration. With 373's I never really used 6th gear. With 4.10's I'm pulling 6th at 70-75mph landing around 16-1800rpms and 2000rpms at 80mph.
When I modded up again to a Lund tuned mono blade... power went up to 716/679rw and I am still McLuvin the 4.10's ! No plans to change a thing .

 

[72MachOne99GT]

Good choice! I keep telling people not to fear the gear. Now that you’ve driven the 4.10/DR combo do you have any reason to think 3.73s would be better?
-J

If I wanted to spend money and not get the maximum reward for the money spent, sure, 3.73s would be better.

 

[Chancey]

That settles it. 4.10’s it is... Thanks for the input guys.