DPE

I'm looking at buying a lightly used base 2010 GT. And it's very base, meaning it has the 3.31 gear in it along with exactly zero options. But it's in great shape and it's cheap and it's Kona Blue so it's pretty.

I read stories about people swapping rear end gears (I'd like a 3.73 for what I plan on doing with it) and ending up with gear whine etc. And while the ring and pinion are only $200 or so from Ford, it looks like the install could be $400+. And it could get cocked up. I'd like to avoid this.

Another option looks to be a complete axle with a 3.73 gear in it from newtakeoff.com. Now of course that's not exactly cheap at just over a grand shipped, but then you're presumably getting an OEM-installed gear and one that's basically new at that.

The question is, that axle you get from newtakeoff, can it literally just be swapped out with the axle on the car now with no driveline issues? I'm confident I could swap the axles fine as I've done quite a bit of mechanical work, but are there any potential issues with this? I'd have an SCT tuner handy to reprogram the car for the new gear; I'm assuming that would do the trick to fix the speedo and such.

Or does the smart guy just find a good shop to swap gears and be done with it? Or does the smarter guy just find a used 2010 with a 3.73 so he doesn't have to mess with swapping gears? Thanks....

Phil

Mr.Ski

i guess one question would be does the car have limited slip? If not, it may be worth it to swap the entire rear axle, and then sell your original. By the time you buy gears, a carrier, and pay someone to set it up, it would definately be worth it to buy the complete one and swap it out yourself it that is within your abilities. If a stock axle will not hold up to what you want to do with the car.... well then you know what you need to do. If you do end up changing out the whole thing, make sure you save yourself some work by just unbolting the brake calipers and hang them with some wire so you wont need to mess with bleeding the brakes.

pdonket

Well you bring up a number of good options. If you're dying for 3.73s, keep looking around a bit and see if you can find a stang with 3.73s stock. But if you really want the car you have in mind, then personally I'd recommend just asking around and finding a good shop that has done a bunch of gear swaps and then have them do it.

dmhines

The newtakeoff rears are only factory if they are 3.31 ... Generally anything higher ... they offer up to a 4.10 ... is setup by a very competent installer. I bought a 3.73 axle from them for my 06 Mustang and it was as quiet as my factory original.

Alec

As long as you use a reputable shop to install the gears you'll be fine. If they whine they're not installed correctly

DPE

Thanks for the advice. As far as I can tell in searching for them, all GTs are limited slip so that's not an issue. Just the gear. I'll be using the car for track days and the 3.31 is just way too tall for that purpose. I don't, however, need any extra stout parts or anything; the engine will stay relatively stock (for awhile, at least) and it won't be drag raced.

I'll have to research if there are any shops in the Kansas City area that handle this kind of stuff. I'd do it myself, but I know the ring and pinion are pretty sensitive and it's one of the very few things I'd rather let someone else do. Swapping the entire axle doesn't look too bad (especially if you don't even have to open the brake lines up), but digging into it could be a little iffy.

Thanks again!

Phil

Orion_240

I believe Shelby Automotive (or was it Saleen?) found it easier to just replace the whole rear axles.

4LiterSonic

All GTs have LSD.

OP, it would probably be cheaper to buy a 3.73-equipped axle off of NTO or somewhere and then swap it in on your own. Once you do that, you could sell your 3.31 axle. Axles usually go pretty fast, because us V6 guys are constantly replacing the cheap-*** 7.5s with 8.8s.

MadStang40

I was considering an upgrade to 3.73's and a LSD for my 4.0L with stock 7.5" rear... I heard some claims about gear whine being a wide spread problem in what seems like every gear swap thread (more than likely blown up by those who actually did have gear whine)...

Now, if the OP went the route of buying a 2010 with 3.31's and wanted to go to a Ford dealership to have his gears or complete axle install, will they guarantee their work? Or is there a better type of shop to have these gears installed?

DPE

Well, the dealership just made this an easy decision by selling the car to someone else . So be it. This is some good info, and may apply once again if I find another car at the right price with the wrong gear. I suspect I'll just shop until I find one with a 3.73 though. Also, I've never found this 'officially' in one thread anywhere on the net (though it may well be out there), so I'll share it here. For the 2010 cars (and I'm pretty sure the 2005-2009 cars), rear axle codes are as follows for GTs. As noted above, all GTs are limited slip.

CG = 3.31
CD = 3.55
CB = 3.73

The 2011 cars use different codes. Pretty sure BB is a 3.73, but otherwise I don't know. Not shopping for a 2011 .

Thanks again for the responses.

Phil