so this has been happening since ive gotten if from slc, utah. it is a 87 1/2 ton suburban that has a sas swap done in 94... with what i believe is a 4" or 3" lift and 33's.... anyways when driving on the highway it seems to shake violently while accelerating past 60mph. i believe that it might be the u-joints as 10 bolts are notorious for this. but the transfer case is dropped i believe and it might be loose. it is leaking oil from the front diff. and the trans is slipping. i'm in the process of fixing these problems, but i just want to know what yalls opinions on what is causing this shaking... any help would be appreciated.