today my daughter calls and says her dash of her 87 300d is ticking every few seconds in town and ticks more at highway speeds.her speedo was ticking every tenth of a mile.,assuming the gears are making the noise i took the speedo out and didnt know how to remove the needle to get to the gears.i took the speedo from a 88 190d i have in the yard.it fit and it works ...the original is 140mph and the 190 i put in is 120.will the 120mph i put in be accurate?