Gear Ratio Change (3.31 to 3.73) 5.0L FX4
07-28-2016, 04:21 AM
#71
Size Matters
Thread Starter
07-28-2016, 09:35 AM
#72
New to this forum, thanks for having me. I've got a 2016 xl, RCSB 5.0, 2wd that I'm looking to replace the open diff with a torsen. I know a previous comment mentioned that the mustang 8.8 ring and pinion/diff won't fit the F150 8.8HD. My question is: The 2015-16 Mustang IRS uses a thicker ring and a longer pinion (different) to accommodate for the longer housing? This is different than the old 10bolt 8.8's and even the IRS from the Cobra's. From what I can tell without pulling the diff cover off is that the pinion length on our HD "super" 8.8's is longer and that the diff is the same as the mustangs. So why won't a ring & pinion/ torsen diff from a 2015-16 mustang work with our SRA? I'm assuming ford would standardize like they have with all of the previous 8.8's to save cost?
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sammyboy (07-28-2016)
07-28-2016, 11:15 AM
#73
Senior Member
07-28-2016, 12:51 PM
#74
Yes I got them swapped and the truck is fantastic now! No lag when taking off up a hill. It doesn't down shift from 6-4 anymore and it gets the same gas mileage as before. I took it on a road trip from SC to FL and it performed flawlessly. I would suggest if anyone is thinking about changing gears if you have 35's and 3.31 then change them to 3.73 I wouldn't go to a 4.10 I think that would be to much.
07-28-2016, 03:32 PM
#75
I still think 4.10s would be ideal.... regardless of the underdrive gears, the o/d gears are still the same as they always have been. 60-65mph with 4:10s would be the ideal zone IMO. if you drive 70-75, the 3.73s could be better but really shedding the mpg but moving that fast in a lifted brick.
a lot of the GM guys run 4.56s with 35s...
a lot of the GM guys run 4.56s with 35s...
07-28-2016, 03:36 PM
#76
Size Matters
Thread Starter
Yes I got them swapped and the truck is fantastic now! No lag when taking off up a hill. It doesn't down shift from 6-4 anymore and it gets the same gas mileage as before. I took it on a road trip from SC to FL and it performed flawlessly. I would suggest if anyone is thinking about changing gears if you have 35's and 3.31 then change them to 3.73 I wouldn't go to a 4.10 I think that would be to much.
07-28-2016, 03:44 PM
#77
That's why I don't drive a GM the mpg would drop out of the sky on that kind of gear for 35's and speaking from experience I actually got better gas mileage driving on I-85 to and through Atlanta with the 3.73 than I think you would with 4.10. It's just too high of rpm with 4.10. The 3.73 puts you right at 2000 rpm.
05-31-2017, 05:52 PM
#78
F-150 Noob
Yes I got them swapped and the truck is fantastic now! No lag when taking off up a hill. It doesn't down shift from 6-4 anymore and it gets the same gas mileage as before. I took it on a road trip from SC to FL and it performed flawlessly. I would suggest if anyone is thinking about changing gears if you have 35's and 3.31 then change them to 3.73 I wouldn't go to a 4.10 I think that would be to much.
Sorry to revive such an old thread, but who is doing all your guys' ring and pinion swaps? I've called 5 local ford dealers and not a single one of them will do it! Yall having transmission shops in your area do the work?
05-31-2017, 05:56 PM
#79
Size Matters
Thread Starter
05-31-2017, 06:33 PM
#80
Senior Member
What did Bozard charge? Was it the main shop or their after market shop? Are they going warranty their work? They do good work, I bought my truck from them and they installed my level. Good dealership.