Late in the 1983 model year, special police speedometers were released to retain calibration over a wide range of temperatures. These speedometers, and those used in 1984 and future model years, will not be repairable. (Parts lists will not be published, nor service parts made available.)
The special police speedometers released to date are listed below:
P/N APPLICATION ---- ------------ 25076605 1983-84 Impala and Caprice - U.S. - 3 spd
25077842 1983-84 Impala and Caprice - U.S. - 4 spd
25076129 1984 Celebrity - U.S.
25076130 1984 Celebrity - Canadian
These speedometers must be replaced as assemblies, rather than repaired by components.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.