Help! - Loss of acceleration after new rear end.
05-26-2008, 04:26 PM
#21
6th Gear Member
Join Date: Jan 2008
Location: North Pole
Posts: 6,716
RE: Help! - Loss of acceleration after new rear end.
ORIGINAL: GT Newbie
I have the 3:31 gears and mine accelerates like a bat out of hell in passing gear (both in 3rd and in 4th), so I doubt if that's the cause of his problem.
ORIGINAL: howarmat
My first guess would be that you have 3.31s installed now instead of 3.55. Other than that i dont know
My first guess would be that you have 3.31s installed now instead of 3.55. Other than that i dont know
I have the 3:31 gears and mine accelerates like a bat out of hell in passing gear (both in 3rd and in 4th), so I doubt if that's the cause of his problem.
05-26-2008, 05:48 PM
#22
1st Gear Member
Join Date: Feb 2008
Posts: 54
RE: Help! - Loss of acceleration after new rear end.
I would check your gear ratio first,raise the rear end, put a mark on a tire and a mark on the ground for a referance point,Mark the drive shaft rotate the tire 10 times count the driveshaft revolutions divide by 10= gear ratio. 33 revs. div X 10 = 3.31 35revs X 10 = 3.55.If it checks out to 3.55 you may have other problems.Good luck keep us informed.
05-26-2008, 06:59 PM
#24
Thread Starter
Join Date: May 2008
Posts: 4
RE: Help! - Loss of acceleration after new rear end.
It was stock tuned. The dealer swears that the replaced gears were stamped 3.55:1 but it sure feels more like a 3.31. I am dropping it back off at another dealer tomorrow to take a look at it. I will ask them about the computer to make sure the other dealer did not reprogram it incorrectly. Thanks!
05-26-2008, 07:20 PM
#25
Thread Starter
Join Date: May 2008
Posts: 4
RE: Help! - Loss of acceleration after new rear end.
My 08 came with the 3.55 and it had incredible acceleration. The only reason we took it back to the dealer was because the noise in the rear was getting much louder after the first thousand miles. We bought the car brand new with under 10 miles on it. It would plant you back in your seat and you barely had to touch the pedal.
Whatever that dealer did when they replaced the gears sure did neuter my Stang! My gut is telling me that the losers put in 331's and are lying to me. I am going to have this new dealer show me the stamp on the gears tomorrow and also verifythat they have the correct computer settings. Oh and I will be calling Ford customer service tomorrow as well and asking them to put me in contact with a regional rep. I am not going to let that dealer get away with this. Nobody messes with my Pony and walks away without a fight!
Whatever that dealer did when they replaced the gears sure did neuter my Stang! My gut is telling me that the losers put in 331's and are lying to me. I am going to have this new dealer show me the stamp on the gears tomorrow and also verifythat they have the correct computer settings. Oh and I will be calling Ford customer service tomorrow as well and asking them to put me in contact with a regional rep. I am not going to let that dealer get away with this. Nobody messes with my Pony and walks away without a fight!
05-26-2008, 11:18 PM
#26
5th Gear Member
Join Date: Sep 2007
Location: Tampa, FL
Posts: 2,181
RE: Help! - Loss of acceleration after new rear end.
It has to be something else. I don't think just going from 3.55 to 3.31 would be that huge of a difference. At least not as big as you are describing it. I mean, I went from 3.31's to 3.73s and I thought it wasa good upgrade, but again, not as much as you think you have lost. Let us know what you find out.
05-26-2008, 11:48 PM
#27
Multi-Tasking Moderator!
Join Date: Nov 2006
Location: Detroit Rock City!
Posts: 15,618
RE: Help! - Loss of acceleration after new rear end.
that is correct!
ORIGINAL: Riptide
Even 07/08 manuals have 3.55 rear ends? I thought it became an option (+$200) and the 3.31 became the standard regardless of auto/manual in those year models.
Even 07/08 manuals have 3.55 rear ends? I thought it became an option (+$200) and the 3.31 became the standard regardless of auto/manual in those year models.
05-27-2008, 12:40 AM
#29
1st Gear Member
Join Date: Apr 2008
Location: Daytona Beach Fl
Posts: 145
RE: Help! - Loss of acceleration after new rear end.
In 05 and 06 the 3.55 gears were stock in 07 and 08 3.31's are stock and 3.55's are an option. My 08 came with 3.31's. I had 3.73's installed. It was a good upgrade but not a huge change and 3.55 to 3.31 would be noticable but not as big as that.
If you had the same gears installed I don't see why they would need to reflash the computer and even if they didtheywould only modify the program for the speedo. They wouldn't replace the program with another one.
Is there any noise now? Maybe something is binding like bearings or maybe the backlash is wrong.I hope you get this resolved let us know how it turns out.
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If you had the same gears installed I don't see why they would need to reflash the computer and even if they didtheywould only modify the program for the speedo. They wouldn't replace the program with another one.
Is there any noise now? Maybe something is binding like bearings or maybe the backlash is wrong.I hope you get this resolved let us know how it turns out.
[sm=badbadbad.gif] [sm=signs003.gif]
05-27-2008, 03:12 AM
#30
6th Gear Member
Join Date: Apr 2005
Location: West Los Angeles
Posts: 5,390
RE: Help! - Loss of acceleration after new rear end.
yeah, just giving you 3.31's instead of 3.55's isn't going to be that noticeable. They are pretty close. The differences in power that you describe are not going to be caused by that.
I'd check the #'s just to check all the work those morons did, but it sounds more like they screwed with something else. Either the tune or a sensor somewhere.
I'd check the #'s just to check all the work those morons did, but it sounds more like they screwed with something else. Either the tune or a sensor somewhere.
