Hello, i was looking to upgrade to 4.10 gear ratio to gain acceleration i have 33 tires on right now on a 2010 f150 4.6 (cat back exhaust with a cold air).My mechanic said to not install a new gear in as that would be bad for the truck and just to tune with a computer tuner the gear ratio I already have to 4.10 even tho its not 4.10. Thoughts?

 

Find a new mechanic.

I'm not saying changing to 4.10 gears is good or bad, more information about your truck would help. But his explanation doesn't make sense.

 

Program for the 4.10s when you have the 4.10s. Upgrading the gears is only as bad as the install. There's nothing bad about it and it puts less strain on your drive train due to gear reduction. Do you know your current gear ratio?

 

If you have an 'open' tune and you have 3.55 gears and change to 4.10 gears, you can change the tune setting to 4.10. Your speedometer will be right . I agree with what others have said, you need to change your mechanic.

 

Yea i should have 3.55 s I need to check the plate sticker on it. Either way I have a bullydog tuner so I didn't see why there would be any issue just switching the gears and tuning it there. Its as easy as it gets. Anyways ima get someone else to do it. Thanks

 

Just curious as to what voodoo is at play here. I once changed from a 3.42 ratio to a 4.10 and was 25mph off on my speedo before changing the tune to a 4.10. It seems that you would just be throwing your speedo off by doing this without changing the ratio since the computer is now trying to correct for something it doesn't have.

 

I don't really know what your saying? I can only speak for my 2011 Mustangs tune. I went from 3.31 rear gear ratio to 3.73. On my tune I changed the rear gear ratio to 3.73. It made my speedometer right and the shift points on my automatic transmission right. I can also change the RPM (revolutions per mile) of my tire size if I were to change to another tire size if I wanted, to keep the speedometer right and shift points of my transmission.

 

Haha! My apologies, I was reading this earlier really quick and missed a few words. When I read it earlier I thought you were telling him to program his current gear ratio for 4.10s without changing the gears. I'm gonna go wash down the taste of this foot with some beer now.

 

It's OK. I was wasted myself, yesterday when I made my Post.

 

Any mechanic that thinks you can change gear ratios just by telling the ECM the gear ratio has changed is an...

The word idiot just isn't enough.