Northwest GT

I've got an auto. Any downside? Which ones are best (I'm guessing FRPP)?

I did that upgrade on my '96 and it worked out pretty well, but I did get a little noise. Maybe it depends on the skill of the installer.

jasongt06

Only downside might be a slight loss in highway MPG, but might gain MPG for city driving. Best overall gear ratio to have. Yes, use the FRPP gears.

JedCranium

I'm about to go this route of 3.73, I currently have 3.55 on a 2006 with 5 speed manual trans. From what I hear 3.73 is a good all around ratio for more torque at low low end without the sacrifice of top end at high gear rpm's. I think if your driving habits are more along the lines of canyon carving then straight line drags 3.73 are a great choice. FRPP in the first choice, along with that I will upgrade with a Eaton TruTrac carrier.

CaliforniaShaker

I love them in ours. It gives the car the snap off the line that was missing with the 3.31s, mileage around town has actually improved a bit and it'll still knock down 24 mpg on the highway. With the XCal Tuner 87 octane tune it'll chirp the tires on both the 1-2 and 2-3 shifts. If you do a good percentage of highway driving I'd recommend the 3.73s. If you don't do so much highway and want to spend some time at the strip a lot of people would recommend 4.10s.

The FRPP gears do have a better reputation than the Motive gears, if they're installed correctly they should be just as silent as the factory set.

Five Oh Brian

Our cars are heavy and need more gear than that, especially with an automatic transmission. My suggestion: 4.10's or 4.30's for naturally aspirated, turbo, or centrifugal blowers. 3.73's (or 3.55's) for roots and twin screw blowers.

Northwest GT

I'm not a racer, and my car is 99% for transportation (1% for quick transportation)
I think the 3.73's will do the job for my purposes, and FRPP gears should be the ones I'll get

What about the tune I have from the SCT Xcal? Can I adjust for the change myself? I had it set up by Paul's High Performance, and they did a good job. But, it means trying to put back the factory tune and sending it off to Michigan for a week or so. That may be a drag.

By the way, computer literate I aint.

2006stang

I had FRPP 3.73s installed over a year ago and it was the best mod so far. I am also running Dougs race tune. Be prepared for traction issues.....it makes an auto car a whole other animal. My mileage did not suffer......pull 24.5-25 mpg at 65mph on the highway. Use the Xcal to adjust for the new ratio. A 3.90 ratio would be a nice in between 3.73-4.10 choice. I rode in an auto with 4.10s before I decided on the 3.73s and the revs at cruise was a little more that I wanted but your tolerance may vary from mine. Good luck with your mods.

Northwest GT

I have to talk to the guys at SCT to see if I can re program the tuner myself. I also need to save up a few bucks to pay for the install. The gears are relatively cheap, but the best Ford guy hereabouts will likely charge me about $400 for the install, but it will be worth it.

STL-GT

Had my FRPP 3.73s done about 18 months ago, and they made a huge difference in my auto. I'd highly recommend them. No whine or noise after installation by a very qualified shop.

I'm also running Doug's race tune @ 93 octane.

Green96GT

i am thinking about a set of 3.90's in mine.

NastyStang113

I think the 3.73s are the best in automatic cars and the best for blown manual cars. I would only ever do 4.10s if I had a N/A manual or a TR6060. Yes, definitely go with the FRPP gear sets.

CaliforniaShaker

The problem with 3.90s is I don't think FRPP makes them. At least they didn't when I installed both of ours. If you want that ratio you're stuck with Motive.

Green96GT

thats right, you are stuck with motive, but i have heard nothing bad about them though.

STL-GT

When I did my 3.73s, I started out with Motive gears. They whined from the day they were installed, loud enough I could hear them over the radio. Got tired of it and had them replaced with the FRPP gears and the whine disappeared. Not saying that you'll have the same issue with Motive, but I'll never buy another set of their gears.

Dougxox

have FRPP's love them, realy woke things up from the time they went on!

H8IMPORTS

I have 3.90's and love them. The only thing is I want more gear now. LOL So I'm thinking 4.30's now. If you want FRPP gears go 4.10's you won't regret it. Don't Fear the Gear.

JJJTMC

I had the 3.55's and got 24.6 mpg. Put in 4.10's and now get 21.8. No regrets.

RedDragon777

For me i have been 05s with everything from 3.31 (mine) up to 4.30s and so far for a good all around gear 3.73 is the best. I am running Tillmans 93 street race tune right now, but i am thinking about trading in my Xcal 2 for a new Xcal 3 from Tillman with 3 tunes and a set of FRPP 3.73 gears for my next mod.

Cusp

With 3.31s I was pulling down 27+ at 75 Mph. Haven't had the 3.73s on for enough tanks of gas yet. But early results are I am down to about 24 on the freeway. UP about 1 in town if I granny drive it using the gears to keep the RPM down. I can roll in 5th down to about 35 now. Before 40 was the lower limit. Now I need a taller 5th gear.
+1 about what others have written about the Bullitt and its 3.73s. They moved the RPM range up to where the engines torque/power is produced sooner. Car feels lighter. Although I have hit the rev limit getting on the freeway in 2nd where as before I did not. Its looking like I need to be in 3rd before I get to the end of the on ramp now where as before, I could get lane position and drop right into 5th. There is not a huge difference in acceleration. Noticeable but not huge. Over all the car feels like the 3.73s are the gear it should have come with stock.

j0eyabs

I have 3.73's in my 5 speed and I get about 25-31MPG on the freeway.