Ok my main question is about my gears, I have 3.23 in now. Will I notice much of a difference with 3.73 because after searching thru the forums for a bit I dont think I want to go as high as 4.1 because from what I have read, my MPG will start to be affected?
Also is the 7.5 rearend good enough for just bolt ones? My plans are gears, intake, duals, and maybe a performance tune but nothing too radical. Dont plan on tearing up the streets, just want better response and to be able to get in the sweet spot better. So are these basic add ons going to make me want to get an 8.8 with posi?
One more question.. are 8.8 rear ends universal? I found a few new ones on craiglist with 3.73 gears for f-150's ($400) and some used off 89 and 90 mustangs($300). Somebody told me an 8.8 rear end is just that, same on all vehicles.
No you don't need a new rear end but you might want to consider it. Also if you do highway driving, 4.1 might be too high. You will need a tune after installing the gears just so that the speedometer works. As for are they universal, haven't a clue bud.
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2006 Ford Mustang V6 Premium w/ Pony Package (Windveil Blue) - Auto Tran
So tlok and 3.73 gears, keeping the 7.5 rearend. How hard of an install is this for a first timer? Also any guides besides the gear one at AM?
It will go over with the 'boss' alot better if I dont have to pay another 200 on top to have this installed at a garage.
Not something you want to do yourself. It's also not good to re-use gears because they won't wear the same in your car as whatever they came out of. If you can get a $200 install then go for it. And as said you need a tuner to adjust your ECU to the new gears. Last, be nice to your new gears for at least 300 miles so they are broken in correctly and don't whine.
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2008 Dark Candy Red V6 Coupe, 18" SSE Wheels w/ Falken shoes,8" Shorty Antenna, SPEC Stage 1, Airraid CAI, 8.8 w/ 3.31, dual Vortech turbo exhaust, LED Projector Headlights, BBK shorty headers, SEIBON Carbon Fiber heat extractor hood, Sparco Hood Pins, Kenwood 7" touch screen nav/dvd, dos 8" rockford fosgate punch, SS window louvres, Midwest plenum cover, LED taillights, 93 race tune from bamachips, Personalized license plate "GOFASTR" (adds about 15 horses for the license plate) 220hp/232torq
ok will let shop do it. not really wanting to mess it up so better safe than sorry. And I will buy them new... hard to pass on the good craiglist deals tho lol
Ya I have heard that before, but is it really that long and hard of an install thats its really going to be cheaper to buy a whole new rear end and install it rather than just buying the gears and installing them? it just seems pretty hard to believe.
ok lets say I was gunna go with 4.10 gears with my 7.5 end along with a T-lok how much is this gunna cost me to have a ford place put them on?
For a Ford Dealer to install gears and t-lock they are gonna charge you anywhere from $650-$800 for just the install, and you have to supply all the parts. I wouldn't go to a dealership because you don't know how good their gear guy is, esp for that price. Find a local performance shop and get a quote there. Around here, for a gear change, with the shop buying the gears, it's 300 total. All you would have to do is add the price of the t-loc to that and there you go. It's all replaced at the same time so there is no increase in labor. If I were you, I would go to a junkyard, buy the rearend off of a GT, take it to a shop and change out the gears and gear oil, and slap it in.
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2008 Dark Candy Red V6 Coupe, 18" SSE Wheels w/ Falken shoes,8" Shorty Antenna, SPEC Stage 1, Airraid CAI, 8.8 w/ 3.31, dual Vortech turbo exhaust, LED Projector Headlights, BBK shorty headers, SEIBON Carbon Fiber heat extractor hood, Sparco Hood Pins, Kenwood 7" touch screen nav/dvd, dos 8" rockford fosgate punch, SS window louvres, Midwest plenum cover, LED taillights, 93 race tune from bamachips, Personalized license plate "GOFASTR" (adds about 15 horses for the license plate) 220hp/232torq
if youre planning on stopping after a few bolts ons good luck. if you really think i can do it, the 7.5 is plenty. instead of focusing on gears, the main gain will be the lsd.(lsd = limited slip differantial. the ford term. posi is the same, but a GM term) i went with an 8.8 from newtakeoffs cuz im planning on f/i in the near future. imo the biggest change was the tloc. its night and day difference from an open diff. the 8.8s will fit the v6 if it has a cobra pinion flange...available pre installed from newtakeoffs.com. if you install new gears and a t loc in your 7.5 you will be more than happy. my opinion on the gears....3:73 for manual, 4:10 for auto
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2006 4.0 V6 Mustang/X Charger #128 Mods: Too many, check out my profile. Probably currently under modification...
Forget getting gears and T-lock installed in your diff. It's a pain in the butt, expensive, and probably not worth it.
You can buy a ready built diff from places like New Take Off for about $850-900 or so. It takes about 2-3 hours to make the swap in your garage. And then you have your parts that you might be able to sell for a couple of bux.
You'll notice absolutly no performance gain in the 8.8 over the 7.5. But, if you decide to add more speed parts (especially drag slicks), you won't have to worry about it.
You have to think of the ballance for your own needs on this one. With a 4.10 gear ratio it will help you accelerate off the line but will reduce your top end. 3.73 gear ratio will keep some of the low end acceleration as well as some of the top end speed. I bought a new rear 8.8 rear end with 3.73 gears. The only reason I had to get a new rear end is because I am twin turboing my v6. This was much less headach than switching out gears and adding a t-lok. Here is a site where you can get the rear end that comes ready to bold on for a pretty fair price. Ford Mustang V6 8.8 Rear Axle Assembly 3.73:1 05-08 Good luck!!!
Rear end questions 
