New here Plus a Question for anyone!

[1989FordRanger]

Well I will start off as I have a 89 ranger ext cab 4x4 4" suspension and 3" body, Custom made dual shock front hoops made by me, custom bushwacker slotted fenderflares from a chevy half ton to open the wheel wells up more. and my question is that, the tranny sometimes doesn't want to go into reverse after getting worm and sometimes forward but I have only had it happen in 4x4 when I put it back into 2wd it worked fine, the 4x4 does work sometimes not like it does it all the time, but I have not driven it a hole lot to know for sure, as I drive my charger right now in the summer. I took it for a drive and had nuthin wrong put it in 4x4 work fine got around the block and went to acc. and just reved, then I put it back into 2wd and off it went, anyone know why? tranny or transfer case? I believe the transfer case isn't the same as factory as it looks like it had auto transfer case as it has the buttons and wiring, but now it has manual one, witch doesn't really bother me. let me know if u can thxs!