Broken Odometer

I have searched this forum and have found one person with this problem and they weren't concerned with fixing it but rather their mpg. I want it fixed and better yet I need it fixed. Just got a 36,000 4.6L v8 put back in it and the shop is giving me 14 days to get the odometer fixed or my one year warranty will be VOID! Please help me asap. I went to the wrecking yard today to get a cluster and tried to install it... better yet I did install it but it did not work either. The was some kind of curcuit board module that I swapped out with mine and vice versa but it seems to be beyond the cluster itself. Somebody who KNOWS what's the matter Please help me. Time is ticking and I NEED my warranty because I don't trust them much anyway!

Rogerick

They have a sensor usually around the transmission which sends the signal.
Check the connections first sometimes a wire gets broken. The instrument panel has to be the same as the one you replace it with. The junk yard has interchange charts to help with this.
Have Auto Zone or Advance pull your computer codes if a sensor is bad it should show up. Anco will pull transmission codes free also. In Atlanta only one shop has repair parts. The dealer also has to use them. Check where the shop is where you live the dealer will tell you. If you take the cluster in it is cheaper. Strict laws on changing mileage.