Speedometer problem??? Please help.....

[91gt5.0]

I have always had problems with my speedometer. ever since i got the car the needle on the speedo jumps back and forth and the speedo is off. well i bought a gear for it so i could fix it and it didnt do the trick. tonight i just got dont putting in a new tranny and drivetrain in my car. i took it out and not only does the needle jump with the gear installed, but it is also off ALOT. my friend on his motorcycle was going 65 and i was at about 83. what would make it this far off???? what could i do to fix the problem with the MPH being off and also fix my needle from jumping all around while i drive??? any info would be appreciated. thanks.

 

[1979_f100]

do a search for more info on this. It sounds like the magnet that is inside the metal cup deal isnt functioning properly (not calibrated or missaligned), in other words, your speedo= toast and time to bite the $150 bullet.

 

[fiveohGT]

it's something called the speed sensor. it's what the speedo gear clips on to and what the speedo cable plugs into. it's kind of like the middle man. it's located on the driver's side of your transmission towards the top. you can get them at autozone or something for like $30-$40. mine used to do the same thing up to liek 50mph

 

[ss93cobra]

Does the car have aftermarket instrument cluster gauge covers? (white face, etc) because it could be the fact that the needle isn't installed correctly as well.

 

[91gt5.0]

well heres the deal, when i first got the car it did it a little bit but not as bad. the needle just jumped around every now and then. i put some white face gauges on it and after i did that it was really really bad. it does not level out until you are going at least 50. now since i put in the new tranny, and that is all that i changed, it still jumps and now its about 13-17 MPH off. so what do i do?

 

[ss93cobra]

As far as being off on the mph, it could be that the speedo gear isn't correct since the rear axle gears have been changed and the needle could be due to the white face gauge install. If you have a buddy with a spare speedo, perhaps try swapping that out to make sure.

 

[91gt5.0]

well i know the gear at the end of the cable is the right one because i ordered it for 3.55;s. how about the gear inside the tranny??? it wouldnt be my actual speedo cable causing it to jump would it????