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[Invasion1]

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[Guest TurboSedan]

i think you'll be ok considering your Getrag in an '89. my speedometer was spot on with the first Getrag 282 i swapped in, which came from a '90 GP. now i'm using a Getrag from an '88 GP, and it reads about 11% too fast. the only thing that changed in my setup was the trans itself. the VSS from the '88 and '90 trans (and my spare '89 Getrag) are all exactly the same....even the part #. i tried swapping the VSS and the speedo still reads too fast.

 

later i took the VSS out and looked at the exciter ring in the trans. sure enough, the teeth on the exciter ring on the '88 trans are spaced much more closely together, which is obviously giving the speedometer too many pulses per mile. the exciter ring in my '89 and '90 Getrags have teeth that are spaced further apart from each other. so my advice would be to avoid the '88 Getrag 282. i'm not sure why it's different, but i think it might have something to do with the fact that the '88 2.8/5-speed W-bodies had a MAF system altho that's just a guess. good luck