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  • 1996 - 2004 SN95 Mustang -General/Talk-

3.73 vs. 4.10 - My actual experience

  • Thread starter Thread starter merc123
  • Start date Start date Oct 4, 2010
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merc123

Active Member
Jan 27, 2003
420
2
39
North GA
Oct 4, 2010
#1
  • Oct 4, 2010
  • #1
This is a completely unbiased opinion. The reason I say this is because after I killed my other rear end with 3.73s I did a rear end swap (entire rear end). I was supposed to get 3.73 gears from FRPP and apparently they installed 4.10s. Everything on the box said 3.73's including the shipping documentation. I didn't find out until after 2 months of driving the car (which would be today) that it actually has 4.10s. It's like thinking you are about to drink water and it turns out to be a Sprite and all you taste is the soda.

Here are the thoughts and questions I kept asking myself because it didn't seem "normal" compared to my old 3.73's I had. So if you want to know the differences...here ya go.

1. Why am I getting out of 1st gear so quick? These 4.10's rev a lot quicker.

2. I think I'll shift at 2k to save gas. Why am I doing 40 MPH and in 5th gear already? I have to shift at 3k to keep the momentum up with "traffic" and hit 5th pretty quick.

3. Why is my gas mileage so bad? I went from 23-24 MPG on the highway to 20-21 MPG highway. 18 when you mix in traffic.

4. Why is my RPM so high in 5th at 70 MPH? With 3.73's I was about 2200 or so and with these 4.10's I'm at 2500.

5. I'm so glad I got rid of those 3.27 gears I had. I can pass cars so much easier in 5th gear without downshifting. Fact is you can pass cars without downshifting with 3.73's too....it's just easier with 4.10's since you're almost to 3k on the highway!

6. Why are my tires spinning? They never used to spin like this before.

Those are all I can remember for now. One issue I did take note on after figuring out I had 4.10's was my SpeedCal. I have it set for 3.73 gears, not 4.10s and my speedo is only 2 MPH less than my GPS.
 

N8Dogg98

15 Year Member
Apr 4, 2005
3,872
238
184
MN
Oct 4, 2010
#2
  • Oct 4, 2010
  • #2
So what gets your vote... 3.73's or 4.10's?
 

slayerripkdc

15 Year Member
Jun 3, 2003
1,341
16
59
brewster ny
Oct 4, 2010
#3
  • Oct 4, 2010
  • #3
4.56's for the win!!!! lol
 
J

Justa2V

New Member
Oct 4, 2010
2
1
0
Manteca, Ca
Oct 4, 2010
#4
  • Oct 4, 2010
  • #4
I dunno, I've had 4:10s for a while now and I'm glad I switched from 3:73s. I didn't notice a big difference in gas mileage really but maybe it's a bit different for automatics.
 
Reactions: WarPony40

streethorse

15 Year Member
Oct 8, 2005
1,042
6
58
Dallas Texas
Oct 4, 2010
#5
  • Oct 4, 2010
  • #5
When you dont drive much per day average your not going to notice much
difference in mpg between 3.27, 3.73, or 4.10..... or care.
When you drive 50 + miles per day ... you care.
Thats why I love the factory 3.27's , 2000 rpm's at 70 mph.
4.10's would be 2500 rpm,s at 70mph ... a 25% increase in gas consumption.
Do the math.
 

Dark04GT

10 Year Member
Apr 27, 2008
758
62
59
NC
Oct 4, 2010
#6
  • Oct 4, 2010
  • #6
streethorse said:
When you dont drive much per day average your not going to notice much
difference in mpg between 3.27, 3.73, or 4.10..... or care.
When you drive 50 + miles per day ... you care.
Thats why I love the factory 3.27's , 2000 rpm's at 70 mph.
4.10's would be 2500 rpm,s at 70mph ... a 25% increase in gas consumption.
Do the math.
Click to expand...

I agree, the stock 3.27's are perfect- too much hwy driving for me too. I like my gas mileage in the mid-upper 20's.

I know the 4.10's are great for the 1/4 mile but I DD my stang and don't need the gear. I don't care how many people say their gas mileage is the same, the simple fact is that is impossible to keep the same gas mileage- you do lose gas mileage (however small, it would add up for me).
 

Tim2002GT

Founding Member
Apr 10, 2002
635
4
29
Tulsa, Oklahoma
Oct 4, 2010
#7
  • Oct 4, 2010
  • #7
5 speeds + 4.10's ftw! I'm only turning 2300 @ 70 mph.
 

merc123

Active Member
Jan 27, 2003
420
2
39
North GA
Oct 5, 2010
#8
  • Oct 5, 2010
  • #8
I have a 5 speed.... It's turning 2500 @ 70.

I originally bought the 3.73's because I have a 100 mile commute, one way and the Stang is the my current DD. I don't really care for the 4.10's for this commute.

If you don't have a long commute to work and just drive the Stang for fun then get the 4.10's. Otherwise go with 3.27 or 3.73s.

Acceleration wise I feel no difference between the two gear sets.
 

Tim2002GT

Founding Member
Apr 10, 2002
635
4
29
Tulsa, Oklahoma
Oct 5, 2010
#9
  • Oct 5, 2010
  • #9
Idk man, my gps is right on with my speedo. @ 2500 rpm I am doing just under 75 mph.


edit: The tranny in my car is from an 04 Mach 1 with the 0.62 5th gear ratio. The GT 3650 5th gear is 0.67 I believe. That is why mine is turning less rpm @ 70 mph than yours.
 

04DarkShadowGT

Member
Jan 31, 2004
474
0
17
Fort Wayne, IN
Oct 5, 2010
#10
  • Oct 5, 2010
  • #10
streethorse said:
When you dont drive much per day average your not going to notice much
difference in mpg between 3.27, 3.73, or 4.10..... or care.
When you drive 50 + miles per day ... you care.
Thats why I love the factory 3.27's , 2000 rpm's at 70 mph.
4.10's would be 2500 rpm,s at 70mph ... a 25% increase in gas consumption.
Do the math.
Click to expand...

I'm not sure you can do a direct correlation to say that 500rpm more is 25% less gas consumption. I don't imagine you would go from 25mpg highway to 18.75mpg highway by going to 4.10 gears.

Hell I can pull 18-19mpg highway with my blown gt, with an auto, 4.10s, 3500 stall.
 

twogts4us

15 Year Member
Apr 1, 2004
4,188
12
79
Dunedin, FL
Oct 5, 2010
#11
  • Oct 5, 2010
  • #11
The difference between 3.73 and 4.10 is huge. My wife's 01 had 4.10s and I thought they were a bit much so I went with 3.73s for my 02 - BIG MISTAKE.
 

streethorse

15 Year Member
Oct 8, 2005
1,042
6
58
Dallas Texas
Oct 5, 2010
#12
  • Oct 5, 2010
  • #12
04DarkShadowGT said:
I'm not sure you can do a direct correlation to say that 500rpm more is 25% less gas consumption. I don't imagine you would go from 25mpg highway to 18.75mpg highway by going to 4.10 gears.

Hell I can pull 18-19mpg highway with my blown gt, with an auto, 4.10s, 3500 stall.
Click to expand...

25% is probably a bit exaggerated on my part. While rpms does affect
mpg somewhat, how hard you accelerate probably plays a bigger part.
But anyway the 3.27 gears are really a benifit for highway driving.
 

98COBRA281

10 Year Member
Nov 24, 2007
1,348
30
59
Port St. Lucie, Florida
Oct 5, 2010
#13
  • Oct 5, 2010
  • #13
slayerripkdc said:
4.56's for the win!!!! lol
Click to expand...

now were talking!! i love my 4.56's!
 

BiminiBlueLX

New Member
Sep 2, 2010
37
0
0
Tucson, AZ
Oct 5, 2010
#14
  • Oct 5, 2010
  • #14
I know you're on the subject of 4.6s, but 5.0s can run high 11s with 3.73s.

See for yourself
 

Tim2002GT

Founding Member
Apr 10, 2002
635
4
29
Tulsa, Oklahoma
Oct 5, 2010
#15
  • Oct 5, 2010
  • #15
streethorse said:
25% is probably a bit exaggerated on my part. While rpms does affect
mpg somewhat, how hard you accelerate probably plays a bigger part.
But anyway the 3.27 gears are really a benifit for highway driving.
Click to expand...

Throttle position plays a big role as well. With 4.10's you don't need as much peddle as you would with 3.73's to accelerate at the same rate. Driving style plays the biggest part of getting good mileage.
 

Tim2002GT

Founding Member
Apr 10, 2002
635
4
29
Tulsa, Oklahoma
Oct 5, 2010
#16
  • Oct 5, 2010
  • #16
BiminiBlueLX said:
I know you're on the subject of 4.6s, but 5.0s can run high 11s with 3.73s.

See for yourself
Click to expand...

True, but typically the 5.0's make a little more low-rpm torque so they don't need as much gearing as a 4.6.
 

merc123

Active Member
Jan 27, 2003
420
2
39
North GA
Oct 5, 2010
#17
  • Oct 5, 2010
  • #17
Very true Tim. I'm still getting used to the throttle and clutch. I'm really jerky on starts at occasion because I can just about slip the clutch without any gas at all.
 
D

Deleted member 38176

Oct 6, 2010
#18
  • Oct 6, 2010
  • #18
BiminiBlueLX said:
I know you're on the subject of 4.6s, but 5.0s can run high 11s with 3.73s.

See for yourself
Click to expand...

WTF? 4.6's can run high 11's with 3.73's too, even with stock 3.27's. Thanks for the pointless post
 

mazen189

Member
Jul 31, 2007
424
0
16
I.E. southern california
Oct 6, 2010
#19
  • Oct 6, 2010
  • #19
I Love my 3.73's. Its a great combination for street, highway use, my daily commute and confortability. If i wanna spin my tires outta third, i have a nozzle I can easily open. On the other hand, I believe the 4v's love the 4.10's more than the 2v's. I might be a bit bias, but, as you stated first, I dont wanna be in 5th gear going 40mph.
 

03_TrueBlue_GT

Active Member
May 5, 2010
810
41
29
Houston, Tx
Oct 6, 2010
#20
  • Oct 6, 2010
  • #20
I love my 3.73's as well but I think it depends a lot on how far you drive every day, I usually drive 45 miles a day to and back from school/work and mostly city driving. Funny things is the 3.73s actually increased my mileage from 17.5 to 19.5mpg with mixed city and highway driving and thats shifting around 2400rpms to hear the flows, and yes I love how the rearend gets loose now when you punch it in a corner..
 
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