13 speed still grinding

I am having a problem with transmission grinding on the high to low range selection. Its an RTO 14613 and I just had the back box rebuilt and it grinds slightly less but still grinds. It doesn't grind every time, kind of intermittent. What is my next move? Am I driving it wrong? All I know is I don't know. Thanks with any help.

 

Do you mean say I'm flipping the range lever down way before i actually make the gear change?
What I try to do is get mph down to about 15 or a little less before I make the change and I think I'm flipping lever and pulling shifter pretty soon after. I will pay better attention next time I run it.

 

That's what i thought too, so i had it replaced. Still grinding though. It is working fine on the up shift, just misbehaving on the occasional down shift.

 

from high range to low range only, so far