what would be causing 5th gear and reverse hard to find?

It happened every time when shifting in to 5th gear or reverse. I dont know when the clutch was replaced. The people I bought it from said it was replaced not longer before their father passed away. Im guessing it was less then a year ago since he passed away thus last october.

Again.....How many miles on truck...WE"LL be okay with guestimating on clutch. Also when they said clutch , what did they mean? some people say clutch and all they mean is the disc , then others ,disc and pressure plate , etc. down to the whole package from the dealer. which would round me out to my last question for now ....what brand IF known?? Thanks.