How are people liking 4.09 gears in the MT82?

[MRGTX]

Can someone help me to help my Ford service department?

The gear swap is done except they didn’t know how to flash the computer to correct the speedometer. What the hell?

They have a call into the hotline to find out what they need to do...which I assumed they would have done as prep for the job.

Any directions or clues would be helpful...
Ugh.

Sponsored

 

[Superspirit]

Can someone help me to help my Ford service department?

The gear swap is done except they didn’t know how to flash the computer to correct the speedometer. What the hell?

They have a call into the hotline to find out what they need to do...which I assumed they would have done as prep for th
Any directions or clues would be helpful...
Ugh.

Forscan Rear Axle Ratio (3.15) BCM 726-12-01 : 013B xxxx xxxx Enable Rear Axle Ratio (3.31) BCM 726-12-01 : 014B xxxx xxxx Enable Rear Axle Ratio (3.55) BCM 726-12-01 : 0163 xxxx xxxx Enable Rear Axle Ratio (3.73) BCM 726-12-01 : 0175 xxxx xxxx Enable Rear Axle Ratio (4.10) BCM 726-12-01 : 019A xxxx xxxx Enable

As a retired auto tech. I cannot believe the service manager at a dealership does not have this knowledge! I would run like HELL from that place. Wouldn't even let them check the oil.

 

[MRGTX]

Forscan Rear Axle Ratio (3.15) BCM 726-12-01 : 013B xxxx xxxx Enable Rear Axle Ratio (3.31) BCM 726-12-01 : 014B xxxx xxxx Enable Rear Axle Ratio (3.55) BCM 726-12-01 : 0163 xxxx xxxx Enable Rear Axle Ratio (3.73) BCM 726-12-01 : 0175 xxxx xxxx Enable Rear Axle Ratio (4.10) BCM 726-12-01 : 019A xxxx xxxx Enable

THANK YOU!!!

 

[Mikepol2]

The gear swap is done except they didn’t know how to flash the computer to correct the speedometer.

Also, the speedo corrects itself, so the flash isn't needed for that (it may be needed for other reasons) - I agree with @Superspirit, that place should go on your do-not-call list!

 

[MRGTX]

I just picked up the car.


Let me put a rest to any notion that this gear ratio change does not require a tune correction. It most absolutely does.

Despite the codes provided by @Superspirit, they had no idea how to correct the as-built configuration or idea of how to change the tune for the new gears. Instead, I would have to come back once they heard back from Ford.

Currently, the car is not happy.

First, there is an error message about the hill hold assist...which is no big deal except that this is tied toe the ABS, which may or may not be working. That’s a problem.

Second, rev match is no longer functional... which is not an emergency (never even tried it before owning this car) but I grew to like it very quickly and it’s a bummer that it’s not there.

Third, the damn revs hang on up shifts...for a weirdly long time. Like a full 2+ seconds. Shifting any sooner than that causes the car to lurch as you would imagine...and it doesn’t seem to happen every time making smooth driving basically impossible.

Finally, there seems to be a slight vibration that wasn’t there before. There’s no howl or whine which might be more typical of improper gear mesh so I’m holding my breath that this is in my head.

This was the first drive where I found myself actively disliking driving this car. Yep, it feels a bit livelier with the new gears but there’s too much else wrong to begin to enjoy it.

So...do I go back to them so they can finish the job when they learn from Ford what they need to do?
Or should I buy a connector and mess with FORScan myself?

 

[K4fxd]

Forescan is pretty easy. Free other than buying the connector. Personally, after asking my local Ford Performance dealer what they wanted for a gear R&R I'd make them do it right.

 

[K4fxd]

Everything I have read about S550 gear swaps say up to 3.73 no tune is necessary, Lower (higher numbers) require a tune.

 

[Superspirit]

I just picked up the car.


Let me put a rest to any notion that this gear ratio change does not require a tune correction. It most absolutely does.

Despite the codes provided by @Superspirit, they had no idea how to correct the as-built configuration or idea of how to change the tune for the new gears. Instead, I would have to come back once they heard back from Ford.

Currently, the car is not happy.

First, there is an error message about the hill hold assist...which is no big deal except that this is tied toe the ABS, which may or may not be working. That’s a problem.

Second, rev match is no longer functional... which is not an emergency (never even tried it before owning this car) but I grew to like it very quickly and it’s a bummer that it’s not there.

Third, the damn revs hang on up shifts...for a weirdly long time. Like a full 2+ seconds. Shifting any sooner than that causes the car to lurch as you would imagine...and it doesn’t seem to happen every time making smooth driving basically impossible.

Finally, there seems to be a slight vibration that wasn’t there before. There’s no howl or whine which might be more typical of improper gear mesh so I’m holding my breath that this is in my head.

This was the first drive where I found myself actively disliking driving this car. Yep, it feels a bit livelier with the new gears but there’s too much else wrong to begin to enjoy it.

So...do I go back to them so they can finish the job when they learn from Ford what they need to do?
Or should I buy a connector and mess with FORScan myself?

It would be nice to see if you can fix it with forscan, have you tried a kam reset? This is the third case of problems I've read after doing this the other two both had aftermarket tunes that were claimed to be the problem. If you could find a member with Forscan to change it in the bcm then we would know if that is all it would take. If you were closer I'd do it for you just to know.

 

[MRGTX]

It would be nice to see if you can fix it with forscan, have you tried a kam reset? This is the third case of problems I've read after doing this the other two both had aftermarket tunes that were claimed to be the problem. If you could find a member with Forscan to change it in the bcm then we would know if that is all it would take. If you were closer I'd do it for you just to know.

Thanks just the same.
Im in CT...I don’t know anyone local who uses ForScan. I’m looking into ordering an adaptor but being optimistic, the service department might get back to me sooner than the adaptor could get here.

Also...yeah. The vibration seems to be significant and persistent. Damn it! Has anyone had this after a ring and pinion and or differential swap? I’m pretty pissed right about now. Because I was too chicken to tear apart the rear end myself, I don’t even know how to diagnose it.

 

[opengl]

Let me put a rest to any notion that this gear ratio change does not require a tune correction. It most absolutely does.

IIRC the guys who have swapped to 4.09's with no issues or tune needed are 2018 cars. I know the Bullits have issues, but I think I recall some speculating that 2019+ cars require more to be done for unknown reasons.

 

[ice445]

Thanks just the same.
Im in CT...I don’t know anyone local who uses ForScan. I’m looking into ordering an adaptor but being optimistic, the service department might get back to me sooner than the adaptor could get here.

Also...yeah. The vibration seems to be significant and persistent. Damn it! Has anyone had this after a ring and pinion and or differential swap? I’m pretty pissed right about now. Because I was too chicken to tear apart the rear end myself, I don’t even know how to diagnose it.

Driveshaft gets dropped to do this job, id wager it wasn't reinstalled correctly or the flanges were overtightened. Seems like on 2020 cars that this swap is a nightmare to figure out, I don't know of anyone with a 2020 that has gotten it to work.

 

[MRGTX]

Nobody with a 2020 has gotten this to work?!

Forscan cable has been ordered...sounds like that might not help.

 

[Superspirit]

These complications I keep reading about are the reason my gears are setting in the box. I have a 19 and I'm waiting for the Ford performance tune to arrive so that the install will go smoothly. As it has the option to change it in the tune. It would be really nice to know if it can be done with just forscan.

 

[MRGTX]

These complications I keep reading about are the reason my gears are setting in the box. I have a 19 and I'm waiting for the Ford performance tune to arrive so that the install will go smoothly. As it has the option to change it in the tune. It would be really nice to know if it can be done with just forscan.

I never even suspected that there were significant changes between 18 and 2019/20 that would make any difference.

My cable will be here Tuesday. I’ll keep you posted, assuming I can get the ForScan software working. It doesn’t look hard but neither did the gear swap.

 

[K4fxd]

I cannot find a 2020 model year tune to check but I have found a 2019 and I can set the final gear ratio "auto correct" in the software. Same as the 15 to 17 years.

Come from the factory set to 3.77 max gear allowed. The factory "switch" is set to " learn from BCM" then, Min gear 3.15, and max gear to 3.77

Forscan should be able to set this to the installed gears using the BCM module and using the settings for the 4.10 gear set posted above.

You can search (google?) and find the correct bit sum (probably the wrong term) for the 4.09 gear if that matters to you.

Good luck I wish you were closer.

Using a "hex" calculator I get BCM 726-12-01 : 0199 xxxx xxxx for 4.09 gears

Also might to do a PCM relearn before it works.

This is for setting tire diameter but the info transfers.

https://forscan.org/forum/viewtopic.php?t=2650

Sponsored