Regear to 4.56

[JPaul]

I am going to regear my diffs to 4.56 and a question comes to mind. I know the speedometer will be off since my ECU will be using 4.10 for it's calculations until I can get it reflashed and it uses the speed sensor in the transfer case, but will it be an issue with the traction control until it's updated with the new ratio? I'm not sure if it compares the wheel speed sensors to the transfer case speed sensor and will have an issue when they don't quite agree anymore. I dug around but didn't see any threads that addressed this particular issue.

I may just send in my computers to be programmed by PCM of NC while the axles are being worked on, but turn around time is a concern for me right now.

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[atvspeed4]

I am going to regear my diffs to 4.56 and a question comes to mind. I know the speedometer will be off since my ECU will be using 4.10 for it's calculations until I can get it reflashed and it uses the speed sensor in the transfer case, but will it be an issue with the traction control until it's updated with the new ratio? I'm not sure if it compares the wheel speed sensors to the transfer case speed sensor and will have an issue when they don't quite agree anymore. I dug around but didn't see any threads that addressed this particular issue.

I may just send in my computers to be programmed by PCM of NC while the axles are being worked on, but turn around time is a concern for me right now.

Sent from my SM-N950U using Tapatalk

No issue. We temporarily put 4.56 adventure axles in one of our alphas for moab.

 

[amrg]

If your truck was never calibrated for 35s (Im assuming thats your current size) then your speedo is currently 6% off (reads less than supposed)
When you regear to 4.56, you will end up being 6% off in the other direction (read more than supposed to). It shouldnt be a big deal.
Any local tuner should be able to calibrate it in 5 mins though if you really are worried about the downtime


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[4speedfunk]

Speedo is entirely done via the t-case. Wheel speed sensors are not involved in the speedo display.
Tire size and gearing both play a part in the speedo accuracy. A 4.10 geared truck with stock tires will read fast after you install 4.56s. However it will read slow after you install larger tires. So depending on your gear/tire combo...you may not need any correction. For example: I run 5.13s and 37” tires and it’s very close to stock calibration.