L3750

First time post here. I just bought a L3750 and learning as I go. I am not sure if this is a problem or not. Its a shuttle shift. I am getting a long delay in high range when going from N to forward and it lunges when it catches. I don't know if this has anything to do with it but idle seems a little high about 900rpm.

If this isn't right. What should I check or change?

Thanks, Rich

I have that on the list to change fluid & filter. I forgot to add that I have a FEL on it also.