spedometter part? what is it
 

what is this for exactly? it goes in the tail shaft housing with the speedo gear inside and the speedo cable ataches to it? do i have to use it ?

Re: spedometter part? what is it
 

If this part was installed on your vehicle from the factory then yes you do need it to make sure your speedo reads correctly as it is a gear reduction unit for the speedometer. the drive gear on the tailshaft of the tranny and the driven gear in the tailshaft housing are geared as closely as possible to your given speedo but not quite good enough for a really accurate reading. This reducer helps correct that problem.

Re: spedometter part? what is it
 

ok. i changed the tire size and i replaced the speedo with a new auto meeter speedo. I shouldnt relly need it sense nothing is stock any more, am I corect

Re: spedometter part? what is it
 

you need to go to a speedometer shop and have them calibrate other wise it will be off. I would put it back on because apparently either the trans gear spins faster or speedo spins faster for a reason. but a speedo shop will be able to tell you for sure.