Need Help! Driveshaft or gears?

99nightmare · #1 (**permalink**) 08-19-09, 11:14 AM

I am in a new situation with my wife's new Mustang GT (08 automatic), in the past I have always modded for speed and power and did not worry about anything else. The 08 is my wife's daily driver and our "gas saver" ( idrive a f-150 and have a cammed 99) so after exhaust, cai, and a tune the next mods are either change the gears or swap to an aluminum drive shaft. I have heard that swapping DS gives a seat o fthe pants feeling of changing the rear gears and that would be perfect as it will not hurt the potential mpg. Is that true or should we just go with the 3.73s or the 4.10s? I need all the input I can get here. Thanks in advance

DMSIA07GT/CS · #2 (**permalink**) 08-19-09, 02:13 PM

I changed to 4.10 and am completely happy but I'm not sure were to go for the speedo calibration fix.

ct07gt · #3 (**permalink**) 08-19-09, 02:33 PM

Since the autos come with 3.31 gears, I think a 3.73 would be a good choice. I think the 4.10s would be a little much for an auto that is a daily driver. I am sure that you will lose a little mileage from gears, but it would improve performance more I think. The aluminum driveshaft will increase mileage but will not give as much of a performace gain.

DMSIA, you will need to get your computer reflashed for the new gears, I am not sure if a dealer can do that for you or if you need a handheld tuner. I have not used one.

kooldawg6 · #4 (**permalink**) 08-20-09, 08:42 AM

Gears + install will be cheaper than a DS + install. It could be a toss up as to which of the two is a better mod. Gears will keep your revs higher, keeping you closer to the power band and increase the torque multiplication while the DS will reduce rotating mass, which makes the engine spin easier resulting in better performance.
I've had the 4.10s in mine since early '07 and have put nearly 67K miles on them with not a single issue

That should be a testament on how well they stand up to daily driving duties

I can still squeeze mid 20s MPG on the highway and avg about 19-21 MPG with mixed "spirited driving". Either direction you go, you should be pleased with the result.

Casey4s · #5 (**permalink**) 08-20-09, 03:16 PM

I did both at the same time, but I would go with the gears first if were a choice between the two, I think you'll notice the difference in performance more with the 4:10's.

rays197 · #6 (**permalink**) 08-21-09, 05:19 PM

Quote:

Originally Posted by Casey4s

I did both at the same time, but I would go with the gears first if were a choice between the two, I think you'll notice the difference in performance more with the 4:10's.

I'm gonna agree. I have both sitting in my closing waiting for installation. I am going to buy the ford racing axle girdle and then install everything. I chose the 3.73 gears with my auto and with a Whipple the 3.73 will be enough.

SC67Stang · #7 (**permalink**) 08-22-09, 03:01 PM

I have the alum driveshaft and while it added no HP gains it will give you a seat of the pants bump.
I still have the stock Auto 3.31 gears and with the SC I can spin tires thru 3rd gear if I want to without the use of any brakes, so no gear change for me. Milage is at a playful 15 MPG in the city and 27 HW so changing gears would also lower my milage.

FordTaurusSHO94 · #8 (**permalink**) 08-22-09, 05:18 PM

I did both at the same time. I think the pinion has to come out for the DS, so you may as well do both at the same time if you plan to have both. If it's one or the other, I'd go 4.10's. Well, I'd go 4.30's, but out of the choices you gave, I'd go 4.10s lol.

**walter** · #9 (**permalink**) 08-23-09, 10:03 AM

I'd go with a driveshaft. Put the power back on the road where it belongs not wasted on your drivetrain. You'd be surprised how much of a difference 30lb of rotating mass makes once you ditch the stock two piece boat anchor. Some models offer adaptor plates that won't require you to mess with the pinion at all. Those can be installed easily by a DIY person and are just as good as some of the pinion based kits.

cusp · #10 (**permalink**) 10-30-09, 11:15 PM

I did both at once. 3.73s and a 16Lb Drive shaft. Between the two, the car is more spirited. Shift points are different. about 1/2 to 1 MPG increase in city driving. About - 2 to 3 MPG loss on the highway compared to the stock 3.31s.

whyask · #11 (**permalink**) 10-31-09, 01:05 AM

i did the same as Casey... I had both done at the same time ! Get the gear first = cheaper , then later down the road if u have the cash get the driveshaft ! It does make the car feel more "together" so to speak !

FenixBirdWing · #12 (**permalink**) 10-31-09, 11:46 AM

Hey guys - just bought a new 2009 GT/CS a few months ago!

I'm new to Mustangs and cars in general but i'v e been having a blast and am running the research on diff mods.

How much you guys think the labor would cost on each the alum. driveshaft and gear swap if I got a shop (eg. let's say a Ford dealership) to do it?

Five Oh Brian · #13 (**permalink**) 10-31-09, 10:56 PM

Go with the driveshaft first, as fuel economy is somewhat of a concern for you. I have 4.10's in my 07 GT automatic coupe, and my car is a true daily driver that I use for commuting, and 4.10's are a minimum for our heavy automatics (4.30's would be great, as well).

Alternatively, do a higher rpm stall converter for that automatic. Great bang-for-the-buck that'll cost no more (and usually a little less) than gears or a driveshaft.

blacksheep06 · #14 (**permalink**) 11-01-09, 06:05 PM

I did them at the same time as well, I would highly recommend that route.

I wasn't charged any extra for the DS install.

I went from the stock 3:55 to 4:10 plus the DS and it felt like a completely different animal.

#1stangFAN · #15 (**permalink**) 11-02-09, 05:30 PM

Ive heard that some brands of driveshafts that have the adapter so you dont ahve to pull out the pinion create some noise at the higher speeds its that true or not?

Sparty92 · #16 (**permalink**) 11-03-09, 05:37 PM

Quote:

Originally Posted by blacksheep06

I did them at the same time as well, I would highly recommend that route.

I wasn't charged any extra for the DS install.

I went from the stock 3:55 to 4:10 plus the DS and it felt like a completely different animal.

Do you drive a manual trans car? If yes, how awesome was the transformation? Do you find yourself shifting a LOT sooner (and more often) around town, 1-3rd gears?

If you drive an automatic, then nevermind (and I am truly sorry.)

whyask · #17 (**permalink**) 11-03-09, 08:11 PM

dont be sorry my auto has 430's now with the driveshaft and dear god is she fun to drive ! Of course the TCI Rachet shifter helps ! LOL

Sparty92 · #18 (**permalink**) 11-03-09, 08:14 PM

My comments were directed towards blacksheep.

And while an automatic maybe faster down the 1/4 mile (or not), it certainly isn't a very "involved" driving experience. I liken driver's of automatics as, "riders," as there isn't much but brake, gas and steering to do.