Odometer reads 1/2 but speedo Correct?

[Thumper]

I swapped my cluster recently too a 325i model. Everything is working perfectly except the trip odometer reads about half the actual miles driven. I did a test today and after 6.1 miles by the trip odometer I had traveled 12miles by the highway markers. I was wondering why all of a sudden got bad gas mileage. So what is causing this? I didn't think to check the the main odometer but my guess is it reads the same amount as the trip odometer. Also I have verfied the speedo is correct within 3mph So its not that. Any thoughts? Thanks

[lordofthewaters]

Sound to me like maybe a gear or two were replaced and the wrong thing was used. But of course that's just speculation. Maybe you could take the speedo out and compare the gears with your old one. You won't have to take the speedo apart to do that, the cover's clear.