1988 740GLE wagon auto AW70l tranny 169,000 miles. Just got this car about 2x months ago. As tachometer was erratic usually reading too high I found another cluster on E Bay and replaced my bad tach with that good one. Just wanted to double check my mph/rpm numbers. Does 2500rpm at 60mph and 3000rpm at 70mph sound about right ?? Also as this other cluster had a voltmeter and mine did not I put voltmeter in my cluster. While running it reads to right of noon - like 13 or 14 volts. Is this correct ? I really am not good with electric but I thought electric system was a 12 volt system. Why would the voltmeter read higher then that ? I do think that it is working okay as when I turn on cooling/heater fan voltage drops slightly. Final question : in removing my cluster I had to remove white plastic part that goes over electric plug into back of speedo. It is not re-usable. My local Volvo dealer says they do not sell this as a replacement part as it is not supposed to be removed and removal/part missing indicates cars odometer/mileage may have been tampered with. Anyone know where I can get this part ? Electric plug fits fine without it so I guess it really is no big deal but if I could replace it I would like to. Thanks very much.

P.S. - In this case E Bay was a great used parts source. I paid w/shipping all of $26 for this cluster that I got Tach & voltmeter from. My nearest junkyard(pick n pull)wanted $45 and is 50 miles away($15 in gas & 2 hours in time).