SteelTownStang

I have always performed most of my own "work" on all of my vehicles, however, I have never changed gears before. I would like to swap out my 3.55s for 3.73s or 4.10s. I'm actually leaning towards 4.10s. "Who" other MSF'ers have performed this mod, and how difficult was it on a scale of 1-10. Is there a big difference from 3.55s to 3.73s to 4.10s? If you go with 4.10s, how much top end power will you have to sacrifice for bottom end pull? I'd also replace the cover with the FRPP chrome differential cover. Thanks

don_w

None...

SteelTownStang

Nice ride

69_gt500

Its been said that the best overall gear is a 3.55. Good take-off while managing a good top speed. A driveshaft that moves 3.5 times to the 1 revolution of the wheels is the ideal setup for a street car, correct me if Im wrong.

tom281

I would think that's just a matter of opinion. FWIW, I've had 4.10s installed in my '06 (manual) for almost a year now, and my only regret is (occasionally) I wish I would've went with 4.30s. This seems like a lot of gear, but really when you consider the fact that these motors live on the topend (over 4500 rpm) I feel the 4.10s are very appropriate.

Now on the other hand, I have a '92 GT and I had 3.73s installed in it years ago; and often I wish I would've went with 3.55s as the 5.0 engine doesn't like to rev like these newer modulars do.

As far as installation, I've installed everything on both of my cars EXCEPT the gears; I've just heard too many bad stories about self installs and I figured for $250 labor, I'll let someone else do it.

Tom

wsmatau

I'll echo what Tom said. I haven't switched to 4.10s yet on my '05. I had a 5.0 Cobra that I put 3.73s in and it was too much gear for a daily driver . For a 5.0L I wouldn't go above 3.55.
I've heard good things about our cars with 4.10s but I won't change from stock until I've made the turbo/twinscrew decision.
It does take some experience to get this mod done right the first time. There are a lot of "tricks" to getting the gears to mesh well without extra noise/whining. For me it was worth $200 to save me the headache.

Miserable

My father in law is my mechanic and he's done all the work on my car. He had the rear end apart last week to fix a bad axle seal and I said that if I knew he was going to take everything apart, I would have gotten new axles and gears while he was there. He told me gears are tough to do and that he doesn't mess around with them at all.

Tispco

This is one of the few mods I would not try myself. The gears must be set perfectly. IMO, the proper tools and experience are required!

I have had the gears changed on two Jeeps and on a 4X4 you have to do BOTH axles . Anyways, I had the rear gears go out on one of them (460 miles from home). These gears were installed by a very reputable shop that installs gears everyday and I still had a problem!

If you do highway driving, I would leave the 3.55 or go to 3.73 max. The 4.10+ will increase your RPM's noticeably on the highway and you probably will not be happy with them.

tom281

Just for reference, with 4.10s and manual tranny, along with underdrive pullies, and CMRC deletes, I get just under 24 mpg when cruising at 75mph.

freebass55

I agree with everything. Make sure the shop knows what the hell they are doing before installing gears. The shop I went to said they had never had a set of gears come back. Well guess what, mine whined, badly. I went with the pro5.0 3.90's. The shop said they could do the work. Well, I came to find out later, they got special tools from ford to set up the FRPP gears correctly, and used the same tool to do the 3.90's. I will reiterate...make sure the shop knows what they are doing.

Only thing I disagree with is the highway driving. I am more than happy with the 4.10's on the freeway. I drive ~40 miles a day on the freeway, and I love it. Fifth gear is now a much more usable gear. You are just not cruising in it, but you can actually pass. It's like the o.d. is now gone. I think I need a sixth gear now.

cobra1993ky

I love my 4.30's rpms are 2600 at 70 mph. 4.10's should turn about 100-200 rpms less than 4.30's. Maybe someone with 4.10's can verify this. Dan

06GTwJUICE

I want some 4.10's now...

dang you guys tempt me with every post....

I like road coarses but it sounds like 4.10's wouldnt be that bad for top end on most of the coarses and would be ablast driving around locally....

GRAYPNY

I have the 4:10 gears with the 5 speed manual. The perfect combo for the 4.6 engine and transmission. I average 22.5 at 75 mph with a cold air kit and 91 octane. I paid to have them installed.

If you want to have some fun go with the 4:10's! Watch my video below.

69_gt500

How would 4.10's be with a supercharger, and with about 450rwhp?

cobra1993ky

If you are worried about top end speed with 430's , then check this out. You can go 140 mph at 5200 rpm's, and if you had the horsepower, 162 mph at 6000 rpm's . Dont be afraid of steep gears, just the acceleration it will give you !!!

tom281

Hopefully in about 90 days, I'll tell you!

GRAYPNY

Tom is heading for the DARKSIDE!

tom281

Well maybe- my blower fund took a hit earlier this week...... you'll see in a couple of weeks Rich, once the snow melts!

don_w

I'm there now, and have been for a long time. With 450+rwhp, traction on the street will be an issue no matter what IMO. But for freeway cruising, it's no big deal. And at the track... yikes! What a ride!




BTW... use this spreadsheet if you want to compare rpms to speed using various tires sizes and gear ratios.


.

MTAS

4.10's all the way - no regrets at all other than I should have went with 4.30's And I don't race my car - it's a daily driver doing at least 50 miles/day round trip. Man up and don't fear the gear.