DrJekl
Member
- 268
- 1
- 18
- Location
- Clarksville, TN
First my question, then some back ground:
Are speedometers different (function and calibration wise) between models of square body trucks? I know the old style 70s versus 80s is different so let's focus on speedometers that are the same 80s syle used in CUCV, C and K series trucks, blazers, and Subs.
Yes, I know that you must be running the right sleeve/gear combo for your application.
Yes, I know that tire size plays a role. Tires are rock stock so I should be close on the needle if everything else is right.
I installed a Gear Vendor OD unit in my M1031 truck. The speedo was bouncy before the install so I swapped the speedo for a similar mile unit from an 87 K5 Blazer that ran smooth. The GV has the right gear and sleeve in it for the 4.56 gears so I should be in the ball park on posted speed. My GPS has me about 2-3 MPH off before the install and before the needle would go crazy after 35MPH. Now, I am 10 MPH fast but the needle is steady (maybe I should ignore the speed and be happy the needle is steady?).
The GV unit should not be a consideration as the sleeve and gear is on the output just as with your trans or t-case would. The input to the cable is off the tail end of the drive live.
All that said, are all the speedos calibrated the same and in theory this should have been plug and play or is there a calibration difference between models other than your gear and sleeve in the trans/t-case/gear vendor overdrive unit?
Thanks!
Are speedometers different (function and calibration wise) between models of square body trucks? I know the old style 70s versus 80s is different so let's focus on speedometers that are the same 80s syle used in CUCV, C and K series trucks, blazers, and Subs.
Yes, I know that you must be running the right sleeve/gear combo for your application.
Yes, I know that tire size plays a role. Tires are rock stock so I should be close on the needle if everything else is right.
I installed a Gear Vendor OD unit in my M1031 truck. The speedo was bouncy before the install so I swapped the speedo for a similar mile unit from an 87 K5 Blazer that ran smooth. The GV has the right gear and sleeve in it for the 4.56 gears so I should be in the ball park on posted speed. My GPS has me about 2-3 MPH off before the install and before the needle would go crazy after 35MPH. Now, I am 10 MPH fast but the needle is steady (maybe I should ignore the speed and be happy the needle is steady?).
The GV unit should not be a consideration as the sleeve and gear is on the output just as with your trans or t-case would. The input to the cable is off the tail end of the drive live.
All that said, are all the speedos calibrated the same and in theory this should have been plug and play or is there a calibration difference between models other than your gear and sleeve in the trans/t-case/gear vendor overdrive unit?
Thanks!