WHAT REAR AXLE 2011 V6
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AvalancheSVT
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i'd put money on the same as the GT. most everything else is the same on the drivetrain except the ratios in the tranny and ratios in the diff.
yellowV6sport
New Member
All '11 V6's get an 8.8" differential.
The 7.5" was fine in the '94-10 as an OPEN differential (as all left the factory), but borderline when up-graded with a Traction-Lok especially behind a modded six.
The last year a 7.5" Traction-Lok was used in a GT was 1985 and Ford had warrenty issues with people trashing them. Car was under 3000#, wore 225mm wide rubber and the 5.0L put out only 210 HP / 270 ft-lb TQ.
We've now got a 3500# V6 car that can have stickier 235mm wide rubber (Pony or MCA) and 305HP / 280 ft-lb TQ. Even with the narrower base 215 or 225mm tires, a 7.5" T-Lok would have been a huge warrenty problem for Ford.
In 2010, the GT Trak-Pak came with heavy duty 31 Spline axles & differential ... don't know for sure, but I'd guess that all '11 GT's have this as std. now. This would be overkill for the '11 V6, so I'd guess Ford is using '05-10 GT spec 28 spline axles & differential here.
Doug
The 7.5" was fine in the '94-10 as an OPEN differential (as all left the factory), but borderline when up-graded with a Traction-Lok especially behind a modded six.
The last year a 7.5" Traction-Lok was used in a GT was 1985 and Ford had warrenty issues with people trashing them. Car was under 3000#, wore 225mm wide rubber and the 5.0L put out only 210 HP / 270 ft-lb TQ.
We've now got a 3500# V6 car that can have stickier 235mm wide rubber (Pony or MCA) and 305HP / 280 ft-lb TQ. Even with the narrower base 215 or 225mm tires, a 7.5" T-Lok would have been a huge warrenty problem for Ford.
In 2010, the GT Trak-Pak came with heavy duty 31 Spline axles & differential ... don't know for sure, but I'd guess that all '11 GT's have this as std. now. This would be overkill for the '11 V6, so I'd guess Ford is using '05-10 GT spec 28 spline axles & differential here.
Doug
Maybe so, but looking at the trend of the shared parts between the GT and 3.7, can't rule it out. A set of 28 spline axles are no cheaper than 31s, same for the differential. Much less why have 4 part numbers instead of two to keep in stock for assembly. Things should be lean and mean business-wise nowadays. Streamlined.
AvalancheSVT
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thats kinda what i was thinking. 1 axle made costs the company less than having 2-4 axles for the same car. thats like having different model number doors for GT's and V6's. the V6's make enough power and have all the same running gear as the GT now so it would only make perfect sense for the them to do it that way.
yellowV6sport
New Member
The external identifying difference between 31 & 28 spline axles on 9" axle shafts was always solid center on wheel pilot on 31 vs. cast recess on 28. If Ford is still doing this on the 8.8", then I've got 28 spline on my V6.
The std. 2.73 axle assembly could have 28 spline axles & diff as it is not a ratio used on the GT as could the GT A/T which only comes with a 3.15 axle assembly.
The opt. V6 3.31 though IS used on the GT (std. M/T), so it could be shared & 31 spline if this is what Ford is using on the GT's. Then again, maybe just the M/T GT's optional 3.55 and/or 3.73 diff's have the 31 Spline and all others are 28.
Just a bunch of guessing really !!
Doug
The std. 2.73 axle assembly could have 28 spline axles & diff as it is not a ratio used on the GT as could the GT A/T which only comes with a 3.15 axle assembly.
The opt. V6 3.31 though IS used on the GT (std. M/T), so it could be shared & 31 spline if this is what Ford is using on the GT's. Then again, maybe just the M/T GT's optional 3.55 and/or 3.73 diff's have the 31 Spline and all others are 28.
Just a bunch of guessing really !!
Doug
FYI - All '05-'09 GT's had 8.8 with 31 spline axles, V6 cars got a 7.5 with 28 spline axles. Can't say what's in the '10-'11, but I know this is accurate up to the '09 models. Cars with the upgraded diff like the Bullitt and Shelby, or if you checked off the right option box for your GT, still had the same 31 spline axles but the trac-loc diff had stronger clutches for improved limited slip performance.
BTW, the standard rear ratio for AT cars in both V6 and GT's was 3.31:1 (again this is just up to '09, but I think it's probably the same for '10). 2011 V6's dropped that to 2.73 to get their 31 mpg hwy rating. I would think that is the reason some people have commented on the sluggish acceleration in 2011 AT cars, even with the 100+ jump in HP. Not sure what ratio is standard in the 2011 MT V6's, but I've heard the performance difference between MT and AT cars is night and day, so I'm going to guess the MT V6's have a better rear gear like maybe a 3.31, or at least a much lower gearing in 1st and 2nd in the trans than what the AT has.
BTW, the standard rear ratio for AT cars in both V6 and GT's was 3.31:1 (again this is just up to '09, but I think it's probably the same for '10). 2011 V6's dropped that to 2.73 to get their 31 mpg hwy rating. I would think that is the reason some people have commented on the sluggish acceleration in 2011 AT cars, even with the 100+ jump in HP. Not sure what ratio is standard in the 2011 MT V6's, but I've heard the performance difference between MT and AT cars is night and day, so I'm going to guess the MT V6's have a better rear gear like maybe a 3.31, or at least a much lower gearing in 1st and 2nd in the trans than what the AT has.
AvalancheSVT
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you're wrong. the v6's 3.31 is an option that the auto or MT can have.
base is 2.73 for AT and MT cars across the board.
the sluggish is from the slushbox.
Which model year are you referring to? I already said the 2.73 was standard in the '11 V6. If you're talking about '09 cars, then you're wrong, 3.31 is the standard gear for the V6. I know because that's what came standard in my car, not as option, I have the window sticker to prove it.
AvalancheSVT
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this thread is about the 2011's and the 05-10 cars don't matter in any way (especially the V6's) anymore so obviously im not talking about them LOL
Any official word from Ford on what rear end is in the '11 V6?
I'm about to replace my stock 2.73 rear end with 3.73. I don't want to upgrade the gears and then find out that I should've also upgraded the LSD.
I guess my question is: If the '11 V6 stock is a 28 spline LSD do I have to also upgrade to a 31 spline in order to gain the full performance from the 3.73 gears? or will the 3.73s work well with the a 28 spline posi?
thx y'all
--
2011 V6 Premium
Black, Saddle
6 speed Manual
2.73 Rear
I'm about to replace my stock 2.73 rear end with 3.73. I don't want to upgrade the gears and then find out that I should've also upgraded the LSD.
I guess my question is: If the '11 V6 stock is a 28 spline LSD do I have to also upgrade to a 31 spline in order to gain the full performance from the 3.73 gears? or will the 3.73s work well with the a 28 spline posi?
thx y'all
--
2011 V6 Premium
Black, Saddle
6 speed Manual
2.73 Rear
yellowV6sport
New Member
Just did a little research on FRPP, American Muscle, & Late Model Restoration and based on what they show for replacement axles & LSD:
1994-04 std. GT had 28 spline, but the '03-04 Mach 1 got 31 splines
2005-up Ford switched to 31 Spline Axles for all GT's which would mean we have 31 spline Ford Traction-Lok Differential & Axle Shafts in our 2011 V6's.
Blows my mind as only 428 CJ, Boss 302, & Boss 429 had 31 splines in 1969 ... however the widest tires available from the factory back then were F70 (equiv. to 225MM wide) or F60 (Boss 302 & 429, these may have been equiv. to 235MM) and no where near as sticky as todays tires, which makes a big difference as to how HD a rear end needs to be.
Doug
Axle spline count doesn't matter if you are just changing gears.
3.73 is too much gear considering the super low first gear in the two 6 speed tranny's, I would recommend a max of 3.55.
And knowing Ford's history, it wouldn't surprise me at all if they use 28 spline axles in the 2011 V6's 8.8 rear. The bean counters would mandate it just to save 10 cents a unit.
3.73 is too much gear considering the super low first gear in the two 6 speed tranny's, I would recommend a max of 3.55.
And knowing Ford's history, it wouldn't surprise me at all if they use 28 spline axles in the 2011 V6's 8.8 rear. The bean counters would mandate it just to save 10 cents a unit.
yellowV6sport
New Member
Would not surprise me a bit either, but it would probably only be the 2.73 axle as it is the only "V6 only" assy ... the opt. 3.31 is std. in the GT so I think even the bean counters would see the logic of not having two different 3.31 axle assemblies on the production line.
As far as the gear up-grade, there are already a few 2011 V6 owners out there that have upgraded to 3.73's, and I'm sure others out there have done (or plans on doing) 4.10+.
Considering the super low 1st gear in both the A/T & M/T 6-spds, I've also wondered if these guys are going too far.
Comparing 2011 V6 6-Speed M/T 1st gear to earlier V6 5-Speed T5 M/T
(based on 235/50-18 tires on '05-11 & 225/55-16 on '94-04):
The std. 2.73 is the same as 3.08's in a '05-10 or 3.27 in a '94-04 (std. '99-04)
The opt. 3.31 would be 3.74 in a '05-10 or 3.95 in a '94-04
3.55 in an '11 would be 4.01 in a '05-10 or 4.24 in a '94-04
3.73 in an '11 would be 4.21 in a '05-10 or 4.46 in a '94-04
4.10 in an '11 would be 4.63 in a '05-10 or 4.90 in a '94-04
So you '11 owners thinking about a gear up-grade, you may want to do some calculations before swapping in 3.73 or higher gears.
Doug
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