[timmypstyle]

Originally Posted by 4.2L_Guy

yup just looked it has 3.55LS rear end. so for anyone with a tach and stock tires with 3.55 rear end. what are you running at 25to 28 in second and what are you running at 37-40 in 3rd?

you have a tach in yours if you have a digital odometer(cant remember what year yours is). so you can see it. it will not mess anything up and it will reset after you shut off the truck. by reset i mean once you do it, you cant check your mileage until you shut the truck off. then the next time you turn it on or start, it is odometer again. you have to do this every time to get the tach. also has other helpful things on it.
1st-hold in trip odometer button
2nd-turn key to ON(dont start) and wait 5 seconds until the info center says test or something of that sort.
3rd- once you see "test" let go of trip button and keep pressing it as many times as it takes until it says "TACH" or "TAC" (wont be all capital letters if any at all) with numbers after it. my 04 heritage came up Tac 0000. it takes maybe 6 or 8 times for this to come up. once you see this start your truck. it will read in digital and is pretty accurate. like i said once you shut off the truck it goes back to odometer.
test mode also has a dash light bulb check, gauge check and some other stuff. no gas mileage info tho. just try it out so you can see what rpms you are at.