Speedometer correction help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

93M6Formula · 10-04-2021, 02:22 PM

So having an issue on my 82 GMC K1500, Somehow my speedometer was pretty accurate (GPS Verified) with stock 3.08 gears and the 32s I put on. I now just did a 3.73 gear swap and naturally the speedometer was 10 MPH fast. So I did the math and ordered a 42 tooth green gear and pulled out my 40 tooth black gear and the speedometer didn't change... still read 10 MPH fast exactly.

What can possibly cause that with a mechanical speedometer? Note also, this has cruise control so the cables come from there first before the gauges.

10-04-2021, 02:22 PM	#1
93M6Formula Registered User Join Date: Nov 2014 Location: Norfolk,NE Posts: 136	Speedometer correction help So having an issue on my 82 GMC K1500, Somehow my speedometer was pretty accurate (GPS Verified) with stock 3.08 gears and the 32s I put on. I now just did a 3.73 gear swap and naturally the speedometer was 10 MPH fast. So I did the math and ordered a 42 tooth green gear and pulled out my 40 tooth black gear and the speedometer didn't change... still read 10 MPH fast exactly. What can possibly cause that with a mechanical speedometer? Note also, this has cruise control so the cables come from there first before the gauges. __________________ 1982 Sierra Classic K15 RC/LB 6.2L Diesel 700R4 1988 GTA Trans AM 305 TPI 700R4 1993 Formula Firebird LT1 T56 1995 GMC K2500 ECLB 6.5L 4L80E 1996 GMC K3500 CCLB LB7 6L90



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