Usually wrong speedometer was right for a few minutes - The 1947 - Present Chevrolet & GMC Truck Message Board Network

DarkFlounder · 11-10-2015, 07:02 PM

Usually, the speedo on my 72 K2500 is off by a significant amount (showing 35 when I'm going 65). I always figured this was due to the larger tires (35s) and a possible rear axle gear ratio change (PO swapped a Dana70 in place of the Dana60).

However, driving home yesterday, the speedo suddenly jumped and started showing almost the correct speed (showing 61 when I'm doing 65). It maintained this until I slowed for the offramp, and suddenly jumped back down to its usual incorrectness.

Could my speedo actually just need a good cleaning and lubing?

11-10-2015, 07:02 PM	#1
DarkFlounder Registered User Join Date: Nov 2014 Location: Austin, TX Posts: 281	Usually wrong speedometer was right for a few minutes Usually, the speedo on my 72 K2500 is off by a significant amount (showing 35 when I'm going 65). I always figured this was due to the larger tires (35s) and a possible rear axle gear ratio change (PO swapped a Dana70 in place of the Dana60). However, driving home yesterday, the speedo suddenly jumped and started showing almost the correct speed (showing 61 when I'm doing 65). It maintained this until I slowed for the offramp, and suddenly jumped back down to its usual incorrectness. Could my speedo actually just need a good cleaning and lubing? __________________ 72 K2500 Sierra Longbed Wideside 350/TH350/NP205 66 Plymouth Barracuda 225 Slant6



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