Speedomter gear in transmission
 

Hi,

The previous owner had let the speedometer cable hang against the exhaust, which lead to the plastic melting into the cable.
Then the cable stopped rotating and the car was driven like that.

I allready replaced the speedometer cable but still no speedreading in the dash. Now i'm thinking it could be the gear inside the transmission that was destroyed by this.

How hard is it to replace this?

Also, the transmission acts weird. When the car is cold i have to rev i pretty high to get the car going, after about 2 minutes it shifts ok.
Also when i come to a full stop right before it stops it jerks and clunks.
Is this related to the fact that the speed signal is not there?