I want to swap my gears. 3.21 to 3.92?

[IRSmart]

Think about it. How does Traction Control, Stability Control, or Brake Lock Differntial work if there is not a speed sensor at each wheel?

I went from 3.55s to 4.10s. No re-cal.

But those don’t have to measure absolute speed, only the difference in rotation. Cars have had that ability for decades and still had an absolute speed sensor that was separate from an ABS sensor (which is what you’re describing). Every car I’ve ever worked on has had the speed sensor at the transmission output shaft, so changing out the gears would absolutely affect the speedometer in those cases.

 

[crackerjack1957]

2014 Ram 1500....3.55 to 4.56 gear.....speed within 1 mph by gps.....so take it for what its worth

 

[RLJ10X]

And how does the vehicle determine a difference in wheel rotation without a sensor at the wheel?

There's also gps on the dash screen, at least on my truck.

Whatever, dude.

Giant red flag whenever someone self proclaims to be smart. < they usually aren't.

 

[Wild one]

And how does the vehicle determine a difference in wheel rotation without a sensor at the wheel?

There's also gps on the dash screen, at least on my truck.

Whatever, dude.

Giant red flag whenever someone self proclaims to be smart. < they usually aren't.

Let him figure it out on his own,as he doesn't seem to believe anybody here,lol

 

[IRSmart]

And how does the vehicle determine a difference in wheel rotation without a sensor at the wheel?

There's also gps on the dash screen, at least on my truck.

Whatever, dude.

Giant red flag whenever someone self proclaims to be smart. < they usually aren't.

Hey *******, I never said I didn’t believe anyone in here, I was asking WHY the trucks don’t require a tune. Learn to read.

 

[Wild one]

Hey *******, I never said I didn’t believe anyone in here, I was asking WHY the trucks don’t require a tune. Learn to read.

Maybe look in the mirror,several guys have told you exactly why they don't need a tune,if you'd care to actually read what they've been telling you. The trucks read off the wheel speed sensors ,the only thing that'll screw up your speedo is if you change tire sizes,can't make it any planer then that,and you've been told that fact several times,but appear to choose not to believe it.

You do realize everybody else is talking about the 1500 series of trucks don't you,you're 3/4 ton I think still might read off the ring gear.If you have any wires going into the center of your pumpkin,you probably will need a tune for a gear change.If you stick with OEM gear ratio's,the dealer can program your truck for the gear swap,but the 1500's don't require that,as they don't read off the ring gear,like your 3/4 ton does.

 

[IRSmart]

Maybe look in the mirror,several guys have told you exactly why they don't need a tune,if you'd care to actually read what they've been telling you. The trucks read off the wheel speed sensors ,the only thing that'll screw up your speedo is if you change tire sizes,can't make it any planer then that,and you've been told that fact several times,but appear to choose not to believe it.

I’m not disputing that there are wheel speed sensors at each wheel, but there have been wheel speed sensors used for decades still with the need for a single speed sensor, which is usually at the end of the transmission. I find it hard to believe that the truck would use the ABS sensors to measure absolute speed since they each of the 4 wheels typically measures different speeds, which is why the transmission output shaft is a popular place to measure speed since it is an average of all 4 wheels.

It’s not that I don’t believe what you’re saying, I do. It’s obvious that the trucks don’t need to be calibrated, I’m trying to have a conversation and actually learn why. So far the wheel speed sensors (which just sounds unlikely) seems like speculation not backed up with sources. If it’s right, mozel tov, it just doesn’t sound like the most efficient way to do it. The person that suggested that the speed is measured right out of the ring gear in the differential sounds more plausible, since that is a more constant reading, and it is a sensor after the gears, therefore unaffected by their change.

Another question: if the gears don’t require recalibration, why does the AEV ProCal allow for adjustment when changing the gears out? Is that only an HD thing maybe?

 

[crackerjack1957]

Gear ratio can be flashed in BCM........if transmission is not shifiting @ tuned shift points @ WOT with a differential gear change.....found that out thanks to Jay Greene

 

[slacadjuster]

If it was me, I'd look real hard at 4.10s.

3.21s ought to be illegal.

LOL, I hear ya. I have 3.21 in my 2015.

 

[slacadjuster]

2wd just change the rear gear set, if its 4wd sell the truck and get one with 3.92

And how does one go about changing the gear set?? Ya gotta remove the diff cover and such??
I'd like to change the 3.21 s in my 2015 to the 3.92

 

[WilliamS]

And how does one go about changing the gear set?? Ya gotta remove the diff cover and such??
I'd like to change the 3.21 s in my 2015 to the 3.92

If you have never done it, dont try it. There are a ton of measurements the require special tools and levels of precision in the thousandths. its not hard if you have the tools and the know how but I wouldn't begin on my daily driver. Ive done a few in my years on older cars, but its not worth the hassle vs having someone qualified do it.

 

[slacadjuster]

If you have never done it, dont try it. There are a ton of measurements the require special tools and levels of precision in the thousandths. its not hard if you have the tools and the know how but I wouldn't begin on my daily driver. Ive done a few in my years on older cars, but its not worth the hassle vs having someone qualified do it.

Yes, I gathered there was a lot to it, and a lot to know. I'm far from a mechanic, (especially on vehicles today), and if I was going to have that done, I'd definitely be taking it to a shop where they know what to do.
I was just curious more than anything.
Thank you for the feedback

 

[Pull Ya]

People that can CORRECTLY set up a rear end are few and far between, and worth every cent they charge---IMHO
Jay

 

[RunQuick]

I’ve had both 3.21 and 3.92 on the 8 speed and 3.92 definitely pulls harder.

 

[Guy lIPSKY]

Love my 2017 Ram big horn , had her 2 months and every day i find something new didn't know i had on it and as for the dealer i had gotten her from also terrible service department , i got it with 36K miles needed 2 tires replaced due to worn to rib in center from running to high a pressure after being at dealer 6 hrs was told everything was done and paperwork was done before service i go to look at the truck didn't replace the tires that they said would be replaced