78 caprice rearend or tranny problem?

[Chevyman_15237]

I am looking at buying a 78 caprice classic taxi cab. It has the 305 with the 2bbl carb and a turbo 250 or 350 tranny. It fires right up and runs good, but when you start to move and the tranny goes to shift, it makes a noticeable griding/vibration/shuddering and then it shifts. The motor has no hesitation. As the vehicle warms up, it does this for a longer amount of time. Is the tranny or rearend junk, or could it be a universal joint or something like that?

thanks, brian

[kahjdh]

Its probably the trans if you shift and it makes that noise.