I'm getting ready to change a gauge cluster in my father's truck and I heard that if you plug in the new cluster your mileage will reset back to 0 is this true? Dosen't the Computer on the truck remember your mileage?
Thanks,

 

Nope it has to be transferred. I believe the mileage is kept in the PCM and cluster.

 

This man is correct. I got a new cluster with a tranny temp gauge and the mileage had to be programmed into the new cluster.

 

I thought the mileage was stored in the cluster and the Body Control Module (BCM). In any case, when I put my Escalade cluster in I just left the mileage at 0 as my warranty had already expired.

 

Yep, cluster and BCM. You can use the original backplane board but may loose the trans temp and 120mph speedo calibration.
You can get a sticker that attaches to the doorframe indicating the original miles when removed. The dealer cannot do the mileage transfer for you ( for obvious reasons ) but will know where to send it. They need both the new and old cluster.