spacecoastshelby Posted December 14, 2010 Report Share Posted December 14, 2010 Just wondering if outting 4:10s on an automatic daily driver would pose any issues? A few people I have asked locally seemed to think that 3:73s should be the max for the automatics but not sure why? So is there a real technical issue or reason not to go with the 4:10s? Link to comment Share on other sites More sharing options...
2BIGFRED Posted December 14, 2010 Report Share Posted December 14, 2010 Bump I would like to know I was going to put them on this winter but could not figure out if I should or not. Link to comment Share on other sites More sharing options...
csm198 Posted December 15, 2010 Report Share Posted December 15, 2010 You need to ask someone at SAI. John Walker when he was there had recommended to me not to use certain rear ratios for the cars. It has not only to do with your transmission but SCed or not, usage desired..etc... If I could remeber that far back about what whs said I would relay the info to you. But I can't remember . I would IM one of the gurus at shelby to get the strait scoop. Good luck. Link to comment Share on other sites More sharing options...
MustangTom Posted December 16, 2010 Report Share Posted December 16, 2010 Add me to the list of the curious. Link to comment Share on other sites More sharing options...
spacecoastshelby Posted December 17, 2010 Author Report Share Posted December 17, 2010 Not sure who the SAI experts are, but if they want to chime in that would be great! Link to comment Share on other sites More sharing options...
twobjshelbys Posted December 17, 2010 Report Share Posted December 17, 2010 Not sure who the SAI experts are, but if they want to chime in that would be great! I would suggest you talk with Gary Patterson. He's driven more of these cars in many combinations than anyone else and will be able to get you good info. He doesn't participate on this forum often so either email him or call Shelby American. I was going to change mine and decided to leave them alone based on Bud's advice. Don't remember all the reasons but noise was one. Link to comment Share on other sites More sharing options...
shelbymotorsports Posted December 17, 2010 Report Share Posted December 17, 2010 I would suggest you talk with Gary Patterson. He's driven more of these cars in many combinations than anyone else and will be able to get you good info. He doesn't participate on this forum often so either email him or call Shelby American. I was going to change mine and decided to leave them alone based on Bud's advice. Don't remember all the reasons but noise was one. I'm not an expert but as Tony mentioned noise is a factor when you start going above a 3.90 ratio. When the Shelby GT's were being designed there was going to be two different rear end ratios depending if the car was an manual or automatic. I'm not positive but I want to say the manual trans cars were going to be 3.73 ratio. Anyway it was decided that having two different rear end ratios would complicate the build process so a compromise was to fit all SGT's with 3.55s Personally I wouldn't run 4.10 gears with an automatic due to the noise and the additional transmission heat. Steve Link to comment Share on other sites More sharing options...
sgt1020 Posted December 18, 2010 Report Share Posted December 18, 2010 I doubt you would notice a difference going from 3.55 to 3.73. But whats the best gear for road coarse racing? (Not drag racing) Link to comment Share on other sites More sharing options...
spacecoastshelby Posted December 18, 2010 Author Report Share Posted December 18, 2010 Personally I wouldn't run 4.10 gears with an automatic due to the noise and the additional transmission heat. Steve Thats interesting Steve, I would had never considered transmission heat as an issue...figured with high quality lube, it would be fine. Thanks for the input! Link to comment Share on other sites More sharing options...
csm198 Posted December 20, 2010 Report Share Posted December 20, 2010 I put 373 gears in mine and it is fine. If you use other than ford gears you can hear a lot of noise. My ford 373 has some noise but nothing I really notice too much. The noise is normal by the way. Unless its over the top, in that case the thing was not put together well. If you have ever heard detroit lockers in a car nothing after that sounds bad! When I first put detroit locker in my older car (even though I read they were loud) I was still concerned and took it back to the guy that installed it. He laughed and said "you will learn to love the sound" which I did. The only thing was when you were going around 55 the car seemed to yaw back and forth a little. Great for the track or strip. Link to comment Share on other sites More sharing options...
NICK82 Posted December 26, 2010 Report Share Posted December 26, 2010 I had 4.10 gears on my automatic 2005 Mustang GT and it was an awesome daily driver - I put on over 70,000 miles on it before I flipped it. The 4.10's never gave me any trouble - went with Ford Racing and wouldn't recommend anything else. 4.10's automatic will make some nasty launches from the lights, I would do it again. Link to comment Share on other sites More sharing options...
MustangTom Posted December 26, 2010 Report Share Posted December 26, 2010 I've been reading a few threads on other Mustang forums, and think when the time comes I'll be going with 4:10's. I know it's comparing apples to oranges, but when I had my 1991 Mustang 5.0 with automatic, the big debate was whether to go 3:55 or 3:73. I chose 3:55, and noticed a bigger 'seat of the pants' improvement than any of the bolt on mods I had done to the car. I had no problems at all, and after having them for a while I wished I had gone with 3:73. I had 'feared the gear' and went with the supposedly safer choice, but it felt to me that there wouldn't have been any issues with the 3:73's and the extra over the 3:55 would have made the car just right. So unless I hear a good argument against them, I'll be going for the 4:10's. Link to comment Share on other sites More sharing options...
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