2005 Tahoe. 3.42 to 4.10 gears. Will speedo need calibration?

[Broncodave93]

2005 Tahoe LS

wondering if my speedo will be effected. and if so, how can I recalibrate it?

Will probably swap to a 9.5 semi-float from on 08 avalanche. then rebuild and re-gear my front diff.

Thanks! Dave

 

[Scottydoggs]

100% need a trans re tune. speed-o will be off, gear shifts will also be off.

 

[S33k3r]

This might help: https://auto.howstuffworks.com/auto...NQKBDnTn4kiOp3jzOnCFJO0u-U7FLDpsX3NRGgrj4hZt8

 

[Mudsport96]

Well if you just put 37 inch tires on after the swap you wont have to recalibrate....

But really yeah you will need to have that adjusted

 

[rockola1971]

Without a doubt speedo and transmission shift data will all need to be recalibrated. Your speedo is fed a signal via sensor that monitors the TRANNY TAILSHAFT speed. Your true (not measured) speed is being changed at the differential when you change gear or rim/tire sizes so this tailshaft sensor has no idea how fast your axles are turning. Things would be so much easier if GM would just stick the sensor on an axle or the differential for the speedo and use a separate one for transmission data.

 

[swathdiver]

Without a doubt speedo and transmission shift data will all need to be recalibrated. Your speedo is fed a signal via sensor that monitors the TRANNY TAILSHAFT speed. Your true (not measured) speed is being changed at the differential when you change gear or rim/tire sizes so this tailshaft sensor has no idea how fast your axles are turning. Things would be so much easier if GM would just stick the sensor on an axle or the differential for the speedo and use a separate one for transmission data.

GM did that on the 900s but speedo is still driven from trans/transfer case and not wheels.

 

[OR VietVet]

Sounds like a good reason to get Black Bear involved.