badlx87

I have an all stock 87 5.0. I recently changed the speedemeter cable because my one that was on had rusted/broke of inside of the sleeve. I put a brand new one in and my speedometer half works now, 35 mph and under my speedometer bounces around the actual speed that i'm goin. Lets say i'm goin 20, it bounces back and forth from 15-25. occasionally it'll bounce around when i'm cruising at 55, but it seems to onyl do it when its really windy??? But it irons out after a while. Is this problem my speedometer? do i need to put in a different one? and my second question is, what tooth or color of gear do i need to poke on the end that goes in the tranny to make my speedo accurate? it's got 2.73's with 17x9 wheels, 275-40's on the rear. It seems to be off by about 10 mph or so. so reading 50, i'm actually doin 60. Any info is helpful, thanks

mattdel

the bouncing issue is more than likely caused by the way you routed the new cable, you want a big loop, as big as possible. any sudden bends or kinks in the cable will bind it up.
as for the gear, i dont know of a calculator to do that simulation, so i'm of no use.

badlx87

k thanks, the new cable i bought from auto zone is not the same length as the one i pulled of. But i routed it exactly how i pulled the stock one off, and put the cable in both clips, one on drvers floor board and the other on the left of engine bay to keep it from the headers... I'll also reply to my other post you replied to about installing into the speedo. I push it in as hard as i can, any harder and i feel like i'll break the speedo lol. I'm goin to pull out the speedometer in the next few days and try a different one, who knows, maybe i can get it to actually clip to the other one. Thanks for the help.

mattdel

Well if the cable is routed properly, the only other 2 things that would cause the speedo to bounce would be the speedo itself, or the gear on the end of the cable(or the drive gear inside the tranny) is shredded. After all, they are only plastic.

badlx87

yea, i'm pretty sure the gear that goes on the end of the cable and into the tranny is fine, i looked it over when i pulled it out and it didnt look worn. I''l propbably put in a different speedo tomorrow then to see if that fixes. I'm hoping its not the gear in the tranny. Thanks for all the options, its helping me to get to the bottom of this. if i change the speedo tomorrow i'll let you know if that solves anything.

badlx87

well, i put the other speedometer in, the speedo cable clipped right into it with no problem whatsoever. But the other cluster was bad, the guages all jiggled and the tach was way off. So i tried my other one since i knew the guages worked in it. I still had a heck of a time gettin the cable to go on. Its because my hookin in on the back of the cluster doesnt have the "slope" for the **** on the cable to help it slide up and into the grove. But after alot of grunting and farting, and a thumb gash i got it on all the way finally. i need a new speedo cable tho because since i drove without it being in all the way the end of the cable is kinda bent so rather than wobble all over the place the speedo jus barely nudges maybe 1mph within what i'm driving.

badlx87

i also gave the cable as much of a loop as i could, not too much more than i had it at already, but i'm sure it helped. thanks for the tips

stang8689

maybe you got the wrong cable they are different with cruise control