Speedometer help please!!

[collin70k/20]

The other day after we got my truck done we took it out on a test drive. And of course right out of the drive way my dad floors it and the speedometer went right to 100 mph so we thought that might of been the problem. So we turn around and we take off nice and easy at the stop sign and it still pegged at 100mph. The truck is a 1970 k/20 truck with a 350 engine and 400 trans. Any help would be greatly appreciated thanks Collin

[midniteblues]

Wow! Your truck is fast my kids truck takes 4 min. To get too 100. Lol.
seriously you have something stuck in the system. Either the speedo it's self is sticking (lube it). Or the cable is dry and binding(lube it) or the plastic gear in the trans could be shot.
All these are a real easy fix.

I like to take the speedo cables out and submerge them in the oil drain container for a day or so then hang it up to drip dry for another day or two.wipe it off and reinstall.
Of course you could pull the cable out of the sheathing but I've had a p.i.t.a. time trying to get it back in once so I don't do it anymore.

If the plastic gear is chewed up Steves transmissions in Myerstown should have them cheap. But it's more likely it's either the speedo or cable.

[collin70k/20]

Originally Posted by midniteblues

Wow! Your truck is fast my kids truck takes 4 min. To get too 100. Lol.
seriously you have something stuck in the system. Either the speedo it's self is sticking (lube it). Or the cable is dry and binding(lube it) or the plastic gear in the trans could be shot.
All these are a real easy fix.

I like to take the speedo cables out and submerge them in the oil drain container for a day or so then hang it up to drip dry for another day or two.wipe it off and reinstall.
Of course you could pull the cable out of the sheathing but I've had a p.i.t.a. time trying to get it back in once so I don't do it anymore.

If the plastic gear is chewed up Steves transmissions in Myerstown should have them cheap. But it's more likely it's either the speedo or cable.

Ok thanks a lot for the response I appreciate it

[kehstr]

If the speedo is bad, i have one i will trade you for free, pm if you are interested

[collin70k/20]

Originally Posted by kehstr

If the speedo is bad, i have one i will trade you for free, pm if you are interested

Ok thanks I will keep in touch