I have a 2004 4Runner SR5 V6 and I have this issue where i'm driving on the highway and I give it gas and the center diff lock starts flashing on the dash. It happens when going uphill so it seems like it is only when under a load. I didn't think too much about it except for today in rush hour everytime I would accelerate, even when going like 10 miles per hour, it would flicker, except today the 4wd light started flickering too and it started trying to engage violently while driving. I put it in 4wd and drove like that for a while and when I switched it back to 2wd it was fine, with only the center diff lock light still flickering. Any ideas on what it could be or what to check? I just want to get it fixed before any damage occurs.