1994 Infiniti G20 Speedometer stopped working

I have 1994 G20 and the speedo stopped working; the tach works okay for driving around city but when it gets warm it stops working (The tach issue has been this way for over a year, the speedo just stopped 12/23/09).

A friend found a replacement gauge cluster with 20k more than I have though not sure if it came from a 5 spd or automatic.

1) Dealer thought it was the gauge cluster from my phone call only (they have not looked at it yet).
2) someone else thought it might be the VSS

Would the tach work if the VSS was bad? As noted the tach works until it warms up, so I probably have a bad tach, but if it is tied to the VSS than I would except it to not work if the VSS is bad, thus the question.

If it is the gauge cluster is this something that I could do or are there key adjustments that need to be done?

Both AAmco and Dealer will charge to check the VSS.

I am trying to keep costs down.

Thank you,
EdG20