cidsamuth

Well, today, I got back my otherwise unmodified GT. I had the Ford Performance 4.10 rear end gear installed from the stock 3.31.

Upon pickup, in order to adjust the speedometer, I went ahead and installed a Diablosport Predator 93 tune (I had filled up with 93 octane in anticipation of this). It was mostly the "canned" tune, as I only adjusted the axle ratio. I noticed an 'off' for the speed limiter while I was installing the tune, so I turned it off while I was there.

I only got to drive it about 20 miles home tonight, mostly highway. Here are my first impressions, good and bad:

1. The acceleration difference was incredible. $500 for the gears (with labor) and $300 for the tuner . . . I'm not sure I could have gotten a better bang for the buck. I had hoped to see a half second pick up on the 0-60 (based on numbers I had seen comparing the 3.31 to the 3.73), and I'm positive I got it. It was like a different vehicle.
2. The first gear was a little "jerky" under light throttle. I think between the lower ratio rear end and the advanced timing, the car just didn't want to cruise slowly in 1st. Or, perhaps, I just have to get used to driving it with is new personality and touchier throttle.
3. I expected the gas mileage to go down with the 4.10, given most of the driving was highway (I understand the mileage may go up in town). But, I still got 25 mpg going 75-80 mph. I suppose the tune made up for the gear ratio.
4. There was a slight "rotten egg" smell as I pulled into my garage. I'm hoping it goes away, but I am wondering if its a side effect to the new tune.
5. The installer told me to drive easy for the first 200 miles to break in the gears. Allegedly, they can get noisy if they're "abused" before break in. That was disappointing, as you can imagine how badly I wanted to turn the car loose.

Well, that's it. For you heavily modified guys, this will seem elementary. For you guys still running stock, I hope my first impressions help. I'll post more if my observations change.

discodave

Yep, definitely let your gears get about 500 miles on them before you start going ***** out with them. When I got mine installed I really wanted to let loose but you do have to break them in. Some people debate that fact, but it's better to be safe than sorry. You may also want to change your rear diff. fluid after the break in period. When you break the gears in, because they're new, you may get a few metal shavings mixed in with your fluid. Again, not 100 percent necessary, but recommended by some.

cidsamuth

I guess the argument to the break-in period, as well as changing the fluid, is . . .
How is this any different than when the car was new? I don't think most folks changed the fluid when the car was 500 miles old, nor did they take it easy on test drive

discodave

Very true. I definitely didn't break my car in at all. I drove it like I stole it from day one..... But, in this case it might be better to be safe than sorry since you're shelling out 500+ to get the gears done.

jamesgribley

Hey there...nooob here...been lurking around reading...first post...

I see you are in MICH...who did the gears for you?

ALL:
MY CAR: 2010 GT AUTO RAG TOP, BLACK, BLACK TOP, BRICK RED LEATHER
nothing modded yet....

I am considering a TUNE and a CAI...the reveiws seem pretty mixed on an upgraded CAI here....also I want to put diff gears...nothing too agressive...its the wifes main car...I was thinking 3.73...and a 91 tune....with the CAI???

cidsamuth

I had Walsh Motorsports do it in Wixom, MI. They were knowledgeable, flexible, and I highly recommend them.

cidsamuth

UPDATE

The car seemed a little too "jumpy" or "jerky" in 1st gear, so I downgraded the tune to 91 octane. It drives much more confortable and smoother now.

Also, it seems many gas stations only offer 92 octane (and not 93), so this will preclude that being an issue.

Overall, the car feels tons faster, and now it feels smooth too.

jamesgribley

CIDA,


did walsh do your work??...I have been looking at Alternative Auto on the eastside of Detroit...knowledgeable but pricey I think. Owner (Lidio) called me directly back when I left a message...good info..

THnaks for the reply

Gribley

cidsamuth

Yea, Walsch supplied the parts and did the work for $500. Not cheap, but not over the top. I dealt directly with the owner.

Keep in mind, the $500 did not include the speedo recal. I had to use the tuner to do that.

cidsamuth

Another UPDATE -- Member, 7up was kind enough to notify me that the "rotten egg" smell was from the gears (whether the new ones breaking in or the old ones in a box in my trunk!).

Sure enough, the smell has gone away. Thanks.