Speedometer correction gear

[MLynn]

Does anyone know of a source for the speedometer correction gear that goes in the transmission, other than DC? I have talked to two different dealers attempting to get the right gear for my 285 tires. One advised they would need the old gear to match against possible replacements, which made no sense to me. The other found the tire size chart but said it did not go bigger than 265s, so he could not help me. Are these things available somewhere else and how can I determine the correct part number? My truck is a 97, so I guess this is my best action for correcting the speedometer.

 

[zman]

Along a similar vein, does anyone know what tire size options can be programmed into the computer for us electronically controlled 24 valvers??



Steve

 

[DEZLPWR]

Order the Abbott speedometer recalibration module from Jannetty Racing. I have 35" BFG's on my '99 and the speedo is dead on.

 

[OILBRNR]

Unless something has changed though, those of us with 4 wheel ABS the Abbott is not an option.

 

[DEZLPWR]

You are correct in that it will not work with 4 wheel ABS. It DOES work with the 2 wheel ABS (which I have) and it DOES work with 4x4.

 

[DennyDay]

Seed-o Calibration

I may be wrong, but I think the '97 was gear driven from the transmission. Figure the final ratio on your truck, and then figure the ratio and a 1/2 ton with vatious tire sizes, and I think you will find a gear that will put yoy close enough. It's gonna' be tria; and error!!!

Denny

 

[mongoose]

If i remember right another way to get the right gear count is to:



Drive a specified distance via milemarker signs on the freeway. (the longer the better).



check odometer for the miles it says you have traveled. Subtract the actual miles from odometer miles and then multiply that number by the number of teeth on your present gear. The new number will be the number of teeth you need.



ex.



travel 40 miles.

odometer reads 39. 2miles.



40 - 39. 2 = . 8



28 teeth on your present gear



28 x . 8 = 22. 4



you would need to change to a 22 tooth gear.



I'll go back and dig through my old MOPAR magazines and make sure this is right tonight.

 

[DieselDoghouse]

Speedo Gear

Check the links I think Rickson can provide the gears for those of you LUCKY enough to have a speedo cable. For the rest of us until '00 (I think you have a wider rev/mi flashed in the PCM) its Abbott or Superlift Truspeed and really, really good harness connections ('cause I understand that's where alot of the trouble starts). Will be mounting my BFG 285's this weekend