Every since I bought this truck. [1986 Chevy c10 4.3 v6 A.T. transmission] I have heard a scrubbing noise the colder it is out side the worse it is. I first thought it was a front drivers side wheel bearing it was not. Then thought it was the exhaust it was not. I now believe it is either the speedometer or cable. At very low speeds it doesn't make a sound. And on hot days it may start out noisy but as it warms up it fades away. should I oil the cable and speedometer and with what? I thought about white lithium grease in a spray but this to gets stiff in colder weather. Has anyone seen or heard of this with the speedometer or cable? If so what was the fix. Thanks Smitty31.