I've had my car for about 6 years, when it was driven up from Ohio every guage worked. Few months down the road speedometer went, oil guage, heat guage. The only ones still work gas, klm. When I was taking out the old 305, found out that all bolts to the transmission where loose as in hand turn loose, plus one was missing. Could have that been the cause of all of the problems? It is probably a long shot, but I figured I would ask before checking out wiring and electrical issues. An ya I did change the speed sensor. Thanks

 

it may have caused the problems but it more than likely fried the printed circuit on the back of the dash if it grounded out.

check the simple stuff first and see if it fixes the problem ie fuses you can always take the dash plate off and use a ohm meter to see if the gauges are getting a signal