My cherokee has gear 1&2 combined on the gear selector. I really need to be able to hold 1st gear is there anyway to change this easily?

 

You can disconnect the TCM and shift manually, but you will get a CEL as the PCM is unable to communicate with the TCM. What you do is start off in 1-2 and it wont shift into 2nd until 4500 rpm or so, on its own. After that you will have to shift manually into 3rd and 4th. Only other way i know to lockout 2nd is to wire a switch, but ive never dealt with that sort of thing.