About to throw a new ring and pinion in the mustang its an 04 gt and its actually my soon to be wife's car and I have a few questions.


What is the stock gearing for the 5 speed and also the size of the rear end 8.8?

Should I go with Ford racing gears or not and why?

Is there any other mods worth doing its not a daily driver and shes getting about 1k back from taxes to play with.

3.73's or 4.10's for the 5 speed trans. I know fox rear ends were 2.73's or 3.07's

Imo ford racing gears are ok but seemed to be kinda pricey when you could get a yukon or richmond set for the same price. At least that's what I did.

3.73 is a nice all around gear(unless you have 3.55's stock) and is a personal choice after having 4.10s in a foxbox

For that car, if it's an 04 it has the 3650 and I believe 3.27 stock gears. They went to 3.55s in 2005.



3.73, 3.90 or 4.10 for N/A low power applications. Will hang the RPMs a bit high on the highway but will easily get out of it's own way.


If you plan on some light performance mods, I'd go 3.73.

If you plan on supercharging or big power, i'd stick with the 3.27, 3.55 or even 3.73 if you really wanna move. My old cobra made 382/349 and had 3.73's with the stock t45, and that thing used to spin through first and 2nd under anything more than 70% throttle.


As for brand, I'd only use Richmond or Ford Racing. While you're at it, you might want to make sure the posi isn't letting go, and if it is get the diff rebuilt or replaced. While the car's up in the air just hold one tire and spin the other, they should lock.

I disagree with the richmond and ford racing only. Yukon and motive make good ass gears also.

If you regear the car its a smart idea to put new bearings in too. They are cheap and if you're in there its a smart idea.

As for the stock trac-loc unit....dump it. Eaton, yukon, motive and fr sell true posi units. Again worth it if you're in there.

I like the motive gears, they're pretty good quality. If it's just going to be a weekend cruiser and you don't plan on racing it, I'd keep the stock gears or go with 3.55's. I honestly can't see a need for 3.73's or 4.10's in a street cruiser for your wife. As for other mods, get some nice mufflers if you don't have them already and go the dress up route if you haven't done that already. I see no reason to go crazy with performance mods. Give it some rumble and some flash.

and don't forget to recalibrate the speedo. Dunno how you do it on a digital speedo car

ford racing. only way to go. do your research. all the fast guys recommend them

I have used Yukon, Ford Racing and Richmond. They have all withstood the abuse I threw at them although from my understanding the Richmonds didn't like the ext owners abuse.


OH and as far as the actual gearing go with 3.73's if you ever plan to blow or juice the car....4.10's if you are going to keep her n/a

Digital speedos need a tuner to recalibrate.

I've had richmonds and I'm not lying when I say they take the abuse(I didn't really care about my 500 buck rust bucket)


Only thing about richmonds is they are a little on the loud side...but not loud enough to worry.

Im definitely going with the ford racing gears probably the 3.73's after reading the post's... I had richmonds before and they were noticeably loud at times. The posi loc thats in there now is definitely on its way out and I would like to replace it with a decent aftermarket unit that will last awhile and isnt too pricey. Anyone have any recommendations on a unit to go with?

We are replacing all the bearings while we are in there as well as new u joints and balancing the drive shaft.

Eaton diff IMO if you have the pockets. A bit more expensive but the best unit out there. Second choice would be the ford racing Trac-Loc unit.

Agreed 100% Yukon and motive make great gears. A lot of complaints about the richmonds lately from them being too noisy and whining a lot.

I have Moser gears and they seem good.

The trac- loc is only ated for like 350lbs/tq. JUNK IMO. Aurburn carriers suck because theyre non rebuildable. Most eatons can be serviced.

Id say an Eaton uint with 3.55's. plenty of pep for the street with decent gas mileage.

If he has 3.27's the jump to 3.55's is useless, the performance advantage is little to none with such a low gear ratio change. It's like so many people who bitch they dont notice much going 3.55's to 3.73's, the difference is too little to really notice.

if hes not racing it theres no need to change anyway. Just stating an opinion. for a DD theres no need for 3.73's

Its not a DD more of a Sunday driver. We both drive the car and shes wanted gears since the day she got the car. Im going to look into a few differentials but we are def going with 3.73 the 3.55's we wont even notice like mentioned. The pinion bearing seal is leaking anyway so its time to get into the rear end. Right now the car has cat back flowmaster and thats it well be throwing in a cai and eventually a full exhaust with headers if its worth it down the road. Im not going to try and have her buy the eaton if cost that much more than the FR trac loc. Is it worth getting the oem unit rebuilt if its even rebuildable?

IMO it isnt worth getting an OEM unit even if you can rebuild it. Like I said before if you are tearing into the rear end do it right the first time so you dont have to keep tearing into it.


Again just my opinion.