Engine/Transmission (1998.5 - 2002) automagic problems

[Hp]

2000 box stock qc 4x4 long bed with 213k having problems with torque converter lock up/overdrive. tach jumps any where from 100-300 rpms while driving at low speeds 35-55. :--) Other than that no problem runs and pulls like a dream. P. S. Any one know where to find the Kanduco Sweet Tooth grill insert? if so please let me know I think that is about the only thing I want to do to my truck for now...