I know this came up last year. in other posts around july. to dumb the problem down the speedo doesnt work.......but it will work on random occasions. on those occasions that it does work on the open road at 100km it reads 130km. Im glad Holden fitted a speed alert monitor on this model. I have had the car apart more then a dozen times. the gears in the transmission are and the sender are practicly brand new and I cannot see any visible damage to wires. reading through these posts Im starting to think of the previous owner as a bull $%#@ artist.
just get a second hand cluster m8, perferably 1 that works.. Other wise I'm sure there is a member on here that has just done a write up on that sort of thing!