Well its that time of the year again for the bronco to have an issue with the 4wd (you know ridiculously cold and it needs to work) 94 351w converted to manual hubs by po (found out while doing bearings last year). On to the issue, when hubs are locked a hard pull to the left and sometimes a thump thump at low speed when unlocked pulls a lil to the right. U joints are maybe 5 to 6 months old. Sometimes when engaged it really takes some throttle input to pull away from a stop, like more then a quarter petal on flat ground. Ideas? Dont have anywhere out of the cold so exploratory surgery isnt a great option.