cidsamuth

Hello,

I just priced putting 4.10 gears in my 2010 GT (it came with the 3.31). I got the local installer info directly from the Ford Performance website. When I called for a price, the guy was very helpful, and the $500 quoted price (parts and labor) seemed reasonable.

However, he said he was "99% sure" the speedo would NOT need recalibrated, stating that the speedometer sensors are located at the wheels, so the gear ratio would be irrelevant.

This goes contrary to everything I have read. Can anyone comment on their experience changing the rear gear ratios on the 2010 model?

7up

It's almost a matter of semantics here, but the speedo/odo doesn't get recalibrated itself inside your PCM.

The axle ratio, in the PCM, needs to be set to 4.10. This will, in turn, automatically 'calibrate' the speedo/odo correctly.


I'm unsure how many rear gear changes this fellow has done (which may be many), but I'd question his experience on doing it to late(r) model vehicles where reprogramming the PCM is involved.

HTH.

cidsamuth

Thanks.

Since my original post, I have called numerous other places who have said there would need to be a re-calibration. Unfortunately, the general rule seems to be that this elevates the price (parts and labor) to about $700. One guy wanted $1600!

One installer charges $500 (without the speedo change) and recommends just buying the Diablo Predator Tuner for $369 -- allowing me to get the performance hike as well as the speedometer calibration.

I was on board for $500, but closing in on $900 is giving me cold feet.

howarmat

correct, you will want to buy a tuner and might as well get bet CAI while you are at it. Brenspeed and Bama would be great places to shop

gipht1

Get a programmer with a kick *** tune and then adjust the gears within the tune and that will do the trick. If you get them to adjust those settings, you may run into trouble later if you get any work done at the dealer. If they happen to update your pcm, it will mess with the adjustment to the speedo and force you to go back to them again for a fix. If you own the programmer you just adjust it yourself again.

cidsamuth

Okay, just ordered a Diablo Predator, which I found "on sale" for $299 plus $11 shipping. Going to get the 4.10 installed next week, then throw a "canned" 93 tune on myself, adjusting the speedo at the same time.

I don't plan on any further significant modifications -- I'll have $1500 into the car with this, and throwing money at a daily driver never seems like a good idea. Anyway, I figure on putting it back to stock and selling the Predator when its time for trade in a few years.

howarmat

why did you not order one with a custom tune

cidsamuth

With the exception of the 4.10 rear end, my car is unmodified. What "custom" modifications to the tune did I need?