DodgeTalk Forum banner

Status
Not open for further replies.
1 - 20 of 28 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter #1
i currently have 3.55 rear end gear in my 01 1500 2wd and i wanted to put 3.92 in there and i have an auto trans and i know the diff is used for the ABS and VSS can i just swap out gears or is there a computer flash that needs to be done?
 

·
46re(tarded)
Joined
·
352 Posts
As long as you keep your stock carrier (which is most likely open diff) then you'll be fine, just do the gear and get your speedo recalibrated and you'll be good. The ABS ring is on the actual carrier itself, gears can be interchanged and not affect that aspect.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #3
i have a stock limited slip its not an open diff so would there be any problems.... and you are saying that there wont be any problems with the eclectronically controled shiftpoints with the auto transmission with having lower geared final drive??
 

·
Mmmmmmmmm, beer.
Joined
·
2,485 Posts
I would recommend going to at least 4.10 though. Going to 3.92 from 3.55 isn't really even worth the money. You will see not noticeable difference.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #5
well i may go with a 4.10 but i was just worried more about the shift points in the trans to see if the computer needed to be reprogamed with a gear swap
 

·
Mmmmmmmmm, beer.
Joined
·
2,485 Posts
I noticed that after both of my gear installs (4.10, then 4.56), the truck performed better after I did the speedo recalibration. I think this is because the vehicle speed is one of the parameters being monitored and used in various algorithms to control shifts etc... But, I also did a tire size change with both of my gear installs, so this was what was causing the issues, not the gears. If your not changing tire size, then no calibration of any kind should be needed.
 

·
46re(tarded)
Joined
·
352 Posts
The only thing you'll need to calibrate is your speedometer. Shift points might be a little late until you do so, but nothing major. I also recommend at least 4.10s.
 

·
Registered
Joined
·
380 Posts
I replaced my 3.55 with 3.91 but kept the same stock tire size (30" tall). There was a definite improvement. No need to change the speedo cause the tire diameter was the same. Shifted fine. If you do also plan to go to a taller tire, than 4.10s are the way to go.
 

·
46re(tarded)
Joined
·
352 Posts
On '01 and prevoius trucks you absolutely HAVE to recalibrate your speedometer. Speed readings are taken from the output shaft of the transfer case, NOT at the wheels like '02 and newer trucks. Sure you won't notice too much speedometer difference just going to 3.92, but it WILL read higher than you are actually going (rack's up miles) and you will want to recalibrate it. Because you're increasing the revolutions of the output shaft and driveshaft per one revolution of the tires you will read faster, and your speedometer will need recalibrated.
 

·
Mmmmmmmmm, beer.
Joined
·
2,485 Posts
On '01 and prevoius trucks you absolutely HAVE to recalibrate your speedometer. Speed readings are taken from the output shaft of the transfer case, NOT at the wheels like '02 and newer trucks. Sure you won't notice too much speedometer difference just going to 3.92, but it WILL read higher than you are actually going (rack's up miles) and you will want to recalibrate it. Because you're increasing the revolutions of the output shaft and driveshaft per one revolution of the tires you will read faster, and your speedometer will need recalibrated.
Sorry, that's just not true. On '99 and newer trucks, the speedo gets its signal from the PCM, which gets it from a sensor that is mounted on top of the rear axle that reads the tone ring on the rear differential. So the pulses the sensor are picking up do not change with a gear change. One revolution is one revolution, no matter what gears you have. So changing gears does not require any kind of recalibration for speedometer. Tire size changes do though because a taller tire has a larger diameter and will travel further per rotation, thus making one revolution longer then it was with your original tire. This difference is picked up by the speed sensor, and will cause your speedometer to read incorrect.
 

·
Registered
Joined
·
56 Posts
Sorry, that's just not true. On '99 and newer trucks, the speedo gets its signal from the PCM, which gets it from a sensor that is mounted on top of the rear axle that reads the tone ring on the rear differential. So the pulses the sensor are picking up do not change with a gear change. One revolution is one revolution, no matter what gears you have. So changing gears does not require any kind of recalibration for speedometer. Tire size changes do though because a taller tire has a larger diameter and will travel further per rotation, thus making one revolution longer then it was with your original tire. This difference is picked up by the speed sensor, and will cause your speedometer to read incorrect.
Correcto! BUT! Go with 4.10s. You won't be sorry!
 

·
46re(tarded)
Joined
·
352 Posts
I stand corrected. Thanks. 4.10's for sure with stock size tires.
 

·
46re(tarded)
Joined
·
352 Posts
Sweet, so if I switch to 4.10's like I want to, thats all there is to it, just the gear swap, close it up, and drive?
You have to shim correctly pinion depth (usually marked on motive's gears) and shim the carrier side to side for correct contact pattern and backlash.
 

·
R.I.P Big Blue
Joined
·
5,326 Posts
If you haven't done a 9.25 yet, have someone with you that has.
Thats gonna be hard. Most of my friends are chevy guys, and maybe a little gay....

But really, I don't know anyone else with a dodge pickup even, everyone on base here drives cars. There's some trucks, but none of them have even the smallest modifications.
 

·
Registered
Joined
·
376 Posts
I got it online a few years ago for a friend, haven't checked to see if it's still there.
Anyone have a link? May be some good info
 
1 - 20 of 28 Posts
Status
Not open for further replies.
Top