V6 gear swap from 3.15 to 3.73

[alleged]

I am taking my '17 V6 Convertible into the shop tomorrow for a gear swap to 3.73. Has anyone else out there with a V6 had any experience with this?

I've heard different opinions on 3.55 v 3.73, but I'm about to find out for myself...

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[TURTL3]

I am taking my '17 V6 Convertible into the shop tomorrow for a gear swap to 3.73. Has anyone else out there with a V6 had any experience with this?

I've heard different opinions on 3.55 v 3.73, but I'm about to find out for myself...

Well, how do you like it now that it's installed?

 

[alleged]

I just dropped it off today and am expecting to pick it up on Saturday morning. I'll write up my impressions and share them when I get the car back.

 

[wildcatgoal]

Depends on what the power band is for the V6 and your transmission (gearing). And of course your intended use.

Personally, I think I would have chosen the 3.55. But... Torsen is nice to have (assuming that is the sort of kit you installed).

 

[Cascadia_302]

I am taking my '17 V6 Convertible into the shop tomorrow for a gear swap to 3.73. Has anyone else out there with a V6 had any experience with this?

I've heard different opinions on 3.55 v 3.73, but I'm about to find out for myself...

Times up, tell us what you think? BTW, which diff did you go with, Trac Loc or Torsen?

 

[alleged]

It's a long story, but the car was throwing a DTC after the installation, so it went back to shop on Monday. So I drove it on Saturday and Sunday only.

I love the low-end pick-up, but it definitely takes a little bit to adjust to the new shifting patterns. I didn't see a big dive on mileage, barely a change. Big surprise to me was that first gear is still very usable, although you can easily start in second gear now.

I went with the traction-lok differential, so not much to report different there.

I've done a couple of mods on the car (Roush CAI, 73mm throttle body, Borla cat-back exhaust, tune) so I'm eager to get a chance to put it on a dyno at some point and share more data.

Will write a longer-term report when I've had the car back for awhile.

 

[2015 Silver GT]

Did you purchase the Whipple flare tool to make the appropriate change to the BCM?

 

[alleged]

Did you purchase the Whipple flare tool to make the appropriate change to the BCM?

I have an SCT Tuner and adjusted the axle ratio there. Is there something else that's required?

 

[2015 Silver GT]

Gear changes are no longer made through the PCM but rather the BCM. You will need the Whipple flare tool for that. Some guys cars won't even run unless they've used it. That may be why you are getting those DTC codes.

 

[alleged]

The axle ratio and tire size is stored in the BCM for the ABS system. It is no longer stored in the PCM. The problem with this was that it is no longer on the same network technically with the PCM so it requires going through the security to update the information needed to change the values in the BCM. This is why a vin# is needed. Like most of Fords programming regarding the security system, this is par for the course.

Only Whipple and Livernois motor sports so far are licensed or contracted to provide a hand held device that can make these changes, this is the only aftermarket solutions, IDS (only without the past two weeks or so) is now able to do this through the dealer, providing they updated the software and read the documentation. Livernois's device only works with the F150, Whipples does both the Mustang and F150.

I was told however that the tune will need to still have the values set, but the ABS system has a min-max range set so in theory as long as the change in gear ratios or tire size is not too radical it should be able to relearn the values automatically. If it is beyond the range(s) then it will probably throw a code etc. I think going to 3.55s from 3.31s may still be withing these ranges, but 3.73s which are not a factory option anyway might be outside of this.

Found this in another forum for an explanation. And ordered my Whipple tool, too...

 

[DR_]

I'm pretty sure this can be changed in Forscan. I see the settings in there at least but I haven't tried them since I haven't changed gears yet.

 

[alleged]

I'm sure that will update the PCU, but not necessarily the BCU, from what I'm reading. If it does, that would be amazing!

 

[DANA44]

Is the transmission auto or standard ?

 

[alleged]

Is the transmission auto or standard ?

Standard.

 

[Xavier]

I had a 2012 V6 that I upgraded from the stock 2.73 to 3.73. Easily the best mod I ever did to that car. That engine loves being revved up and it felt so much more eager with the shorter ratio. The only downside was that my highway mileage dropped from ~31ish to 26-27 which really isn't that bad.

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