Yea 3.73s are awesome, i got them too, mine was already broken in but still i drove easy just to be safe. Do the 15 min heat cycle and drive easy for 500 mile so your safe on the long run, other than that enjoy
__________________
07 Mustang Pony pkg 4.0L V6
Appearance: Roush hood scoop, rocker panel, custom GT500 chin spoiler, side louvers, racing stripes, shifter bezel, door sill plates, Sequential tail lights
Performance: C&L intake, Bama/Tillman 91 Race tune, SCT X3, Mac dual exhaust kit, OEM Ford 3.73 gears/T-lock on 7.5'
Glad to hear your enjoying them. As this is a future project of my own, do you mind me asking how much it was to have the gears installed? How long did the installation take? Also, you mention an increase in performance- is this with or without a tune? Thanks.
I will pay a gullible newb mechanic, who has no idea of what to charge, maybe 150 at most to install mine, I think thats the going rate, but someone correct me if IM wrong.
I fixed it.
__________________
2002 Mustang GT auto: SLP LM1, 8" shorty antenna, grille delete, coin delete, Cervini front bumper, SCT SF3 93 octane, JLT RAI, Professional Products 75mm TB and Plenum, FRPP 4.10, 10.5x17 DD Bullits, Nitto 555R's
1/4 in 13.828 @ 99.13 "American muscle needs a healthy diet of Foreign rice."
Love my 4.10 gears. But then I don't do any highway driving. MPG wasn't affected because I now can get use out of 5th gear. It was a mod that really made a difference, and it doesn't add any strain to any part of the drive train in front of the axles.
__________________
'06 GT, manual, Satin Silver, lt. grey cloth int., IUP.
MODIFICATIONS - Goodyear F1 GS-D3s; 245/45 on 18x9, 275/40 on 18x10| Progress Technology springs & sway bars| Steeda adj. panhard bar, panhard brace, front control arm brace & bushings| strut tower brace| Tokico D-Spec dampers| CHE adj. LCAs & BMR relocation brackets |drilled & slotted front rotors| C&L intake| BamaChips SCT tune| FRPP 4.10 ring & pinion| Pypes off road H-pipes| FRPP GTA mufflers.
My mechanic explained the reason for the need to break the gears in. He spoke with a tech from Ford racing who explained that even though the gears are made of hardened steel. Going through several heating and cooling cycles keeps the metal from flaking. Anyway after the install he ran it through cycles and then told me to take it easy. The cost to have it done was $400. I dropped the car off while I was out of town and came back and they were done.
As far as a tune I am FI and just reflashed my tune with the updated gear ratio.
Last edited by tbrock; 06-26-2009 at 11:29 PM.
Reason: spelling
3.73's in and love it! 
(Mods in profile)
