Odemeter problom

[blackk5350]

after owning my fine blazer for a little over 6 months i have noticed the mileage go from 187,000 to 201,000 in 6 months. there is no possible way that i have driven 14,000 miles in 6 months because i just dont drive that much. Is there anyway to look at the correct mileage or somehow correct it ? should i get a new spedometer or what? i do have 37" tires if that matters but i would think that it would put the miles on slower

 

[lectric80]

after owning my fine blazer for a little over 6 months i have noticed the mileage go from 187,000 to 201,000 in 6 months. there is no possible way that i have driven 14,000 miles in 6 months because i just dont drive that much. Is there anyway to look at the correct mileage or somehow correct it ? should i get a new spedometer or what? i do have 37" tires if that matters but i would think that it would put the miles on slower

Is your speedometer incorrect? Generally they go hand in hand, for instance my 80 reads way slow from the bigger tires, as a result I can go hundreds of miles before I turn a couple hundred on the odometer. If you speedo is correct, or at least close, then the problem may be the odometer. Bigger tires will make the speedo read slower than actual speed, so for you the speedo should be reading much faster than what you are going, in order for the odometer to be moving that fast.

 

[Mike D]

First off you should calibrate your speedometer for accuracy. Get a watch or stopwatch with a second hand. Get on a straight and level section of Interstate. On the right hand berm there is mile markers ( duh every mile ). Slow to 60 mph when you pass the mile marker note the exact location of the watch second hand. Accurately maintain 60 mph until you pass the next mile marker. Immediately look at the second hand. If you are truely going 60 mph it will take exactly 60 seconds. For accuracy repeat for several mile markers. If it took less than 60 seconds your speedo is too fast. If it took more than 60 seconds your speedo is too slow. If it is off speedup or slow down until you cross a mile marker at exactly 60 seconds. That is your 60 mph point. Now you know how fast or slow your speedo error is. A faster than correct reading will add more miles to your odometer than you actually traveled. Possible when the previous owner put on the 37" tires he may have installed a higher ratio rear axle to help the engine move those big meats.
Once you know how off your true speed is pull the speedo gear out of the transfer case , count the teath. Lets say there is 20 teeth on the speedo gear and your speedo is 9 mph too fast. Then to correct the speedo (and odometer ) you need a speedo gear that has 23 teeth ( 1 tooth more= 3 mph lower, 1 tooth less= 3 mph higher speedo reading ). The odometer will automatically be corrected. Call 4XHeaven with the type of transfer case you have and how far off your speedo is. They should supply you with a used gear with the correct tooth count. The ratio I gave you works for a NP 205 transfer case. I don't have their phone number but they are in upstate New York. They were very helpful.

 

[vortec]

i'd just find out who's been stealing my truck then bringing it back with the same amount of gas so i don't notice .

i'd check these things:

speedo gears
differential gearing
tire size
tranny gearing (most poeple don't mess with that though)

 

[blackk5350]

i'd just find out who's been stealing my truck then bringing it back with the same amount of gas so i don't notice .

i'd check these things:

speedo gears
differential gearing
tire size
tranny gearing (most poeple don't mess with that though)

haha thats a good one but i sleep with my keys everynight so... but thanks alot for all of your insight. i will pull the diff cover off and see if it has a taller gea in it. i assume not because it sucks a@$ in 4th gear and falls on its face. i will check out those sights you all gave me. thanks again and i cant wait to install my 14 bolt soon! with your alls help of course. does anyone wanna come over and help me? i live in louisville,ky