Today my truck started chattering when decelerating in 1st, 2nd, and 3rd gear, 4th gear works fine as always and 5th is currently hanging loosely on the shaft. I am pretty sure this means my transmission is on its way out but, what is making this noise. This may have nothing to do with it but I drove of a steep curb probably 10 minutes before I noticed this noise.
Any help or suggestions would be great, thanks.