I have heard that if you install some 3.73's that you can loose up to 1/3 on gas mileage. true or not? what has yalls experience been w/ 3.73's and fuel mileage? Thanks in advance
***RYAN
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95 GT/CAI/BBK SHORTYs/ O/R H-PIPE/FLOWMASTERS NO CATs/SHORT THROW SHIFTER/FORD RACING 9.0MM WIRES/MSD CAP &ROTOR/MSD COIL/3.73's/UDPs/WELDED ON SUB-FRAME CONNECTORS/NITTO 555's/LOWERED/CLIFFORD ARROW 5.1 ALARM W/KEYLESS/ECLIPSE CD3200 W/i-POD/2 ROCKFORD 8" SUBS !!!NOT A LOOKER!!!
On my 05 I went with 3.73. Now my mileage is around 22 down from about 25 on the highway. Can't tell what my 4.10 does to my 00 cuz I only take that out to race it. Your mileage will suffer a little depending on what is currently in the rear now. Good Luck
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2000 V6 .030 over comp cam, k&n cai,
underdrive pulley set. mac headers, mac h pipe flowmaster catback, aluminum ford racing drive shaft ford racing 4.10 posi. And a 05 V6 for every day use.
The drop will be negligible. It won't be like you watch the gauge drop while driving, it'll be offset by the improvement in torque multiplication to the rear.
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Thats what i thought about the gas mileage, i had my wife call our mechanic friend who said sometimes you can lose fuel mileage when swapping out the gears, and she kinda freaked out, "why do you want to have a car that gets even worse gas mileage" oh,,,,,women just dont understand. the more i think about it i dont know if i want to do the gears myself, i called Dallas Mustang(its just up the street from me and they said $250 to install the gears,pinion seal and bearings carrier bearings axle seals and bearings. sound like an ok price?????
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95 GT/CAI/BBK SHORTYs/ O/R H-PIPE/FLOWMASTERS NO CATs/SHORT THROW SHIFTER/FORD RACING 9.0MM WIRES/MSD CAP &ROTOR/MSD COIL/3.73's/UDPs/WELDED ON SUB-FRAME CONNECTORS/NITTO 555's/LOWERED/CLIFFORD ARROW 5.1 ALARM W/KEYLESS/ECLIPSE CD3200 W/i-POD/2 ROCKFORD 8" SUBS !!!NOT A LOOKER!!!
i called Dallas Mustang(its just up the street from me and they said $250 to install the gears,pinion seal and bearings carrier bearings axle seals and bearings. sound like an ok price?????
I actually increased my mileage when I went from 3.27's up to 3.55's. My last tank of gas (13 gallons) took me 326 miles. That's 25mpg. My previous best on the 3.27's was 286 miles to a tank.
What you need to realise is by changing gears, you get to keep the rpm's up in the "sweet spot" where the engine is running at it's peak for mileage vs. performance. The factory sets the car up so that it is a trade off between mileage vs. performance and I believe they tend to stay on the conservative side.
Now if you went with like a 4.10 or 4.30 or something crazy like that, the rpm's would be too high and out of the "sweet spot" to the point where the fuel consumption is greater.
You also need to consider what the final drive ratio in your transmission is. If your like mine, a .67(T45) and a 3.55 or 3.73, you'd keep the rpm's in the 2200-2400rpm range which is right at the beginning of the cam torque curve. Higher up in the curve, say 2800-3000 and your comprimising fuel mileage for performance. For what it's worth, your '95 T5 is a .68 5th gear ratio. About 25 rpm difference compared to my T45 and the .67.
Hopefully that helped a little and didn't confuse you.
Richard
Tech Support
Tremec TKO, T45 & T56 Transmission Systems
Obamacare my a$$ We are all going to pay for electing this tool.
Remember, it is almost impossible for anyone, myself included, to diagnose a problem over the internet without seeing the car. My advice is simply that, advice based on years of experience. I don't want you or anyone taking my word as gospel. I am trying to give some direction as to what I think may be happening.
stock gears are 2.73 for auto stangs in 94 and 95 i believe i have a 94, and if youve never done gears before or dont know how to do them, take it to a shop its worth it because you really want someone who ABOSOLUTELY KNOWS what they're doing to install them because the slightest gear whine is bad! and you dont want that, and btw i say go with 3.73s
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*1994 Mustang GT Laser Red w/ White Stripes -
GT40P heads, Cobra Upper & Lower Intake w/ 1/2 Spacer, Ford Racing Ceramic Coated Shorties, 2.25" Exhaust No cats, Flowmaster 40s, 3.5" Stainless Steel Tips, Ford Racing 3.73's, K&N CAI, EdelBrock Chrome Valve Covers, 17" Silver Cobra R rims, Brembo Rotors, 94' Cobra Calipers!
*1982 GMC High Sierra6.2l Diesel 4X4-
Custom CAI, Custom 4" Stainless Steel Stacks, 4:56 Posi, Dana 44 F, Dana 70 R, 15" Bullethole Rims, 33" BFG's, A.K.A BigRED
How much fuel mileage will i loose w/ 3.73's 
Your mileage will suffer a little depending on what is currently in the rear now. Good Luck
the more i think about it i dont know if i want to do the gears myself, i called Dallas Mustang(its just up the street from me and they said $250 to install the gears,pinion seal and bearings carrier bearings axle seals and bearings. sound like an ok price?????
