Transmission will not go in to reverse

Have a 2011 f150 I got In it yesterday put it in
reverse it took about 5 seconds it went in to
reverse but the light on reverse was not on the
wrench came on turned off truck started it back up
put it in drive shifted fine put it back in reverse  
light still not on but went in to reverse put it in drive
seemed like it was in 3 or 4 came back home from
work shifted a few times now reverse light comes
on goes right in to reverse  everything is fine for
now anyone  else have this problem was able to
know what's going on with it it's a 2011 f150 xlt
2wd