1994 Ford PU 4 speed manual transmission noise

I recently had the clutch replaced on a Ford 250 7.3 cubic inch pickup. After the clutch was replaced, there is now a rattling sound in the transmission while the vehicle is at idle. The sound is very noticeable at 1000 RPMS and then disappears at higher speeds. It returns as the vehicle decelerates. Prior to getting the clutch replaced, the sound did not exist. The dealer said this is normal for this transmission and to just live with the noise. He also said that 1989-1994 Ford and Chevy vehicles using the same transmission developed noise as they aged. To get rid of the noise, it would cost $2800 to replace the transmission.

There are no troubles with shifting but the noise is very loud and obnoxious. Has anyone had a similar experience?