Hey. I have an 85 LWB that is bone stock. I picked it up with only 75000 original miles on it. It has a 305 with a 3-speed automatic. I'm not sure what tranny it is, I was just told it is a 3-speed. The truck has a drive line vibration at highway speeds 55-65. Some mechanic friends of mine have had a few of these trucks and they said that this is common with this tranny, and it is coming from the tranny. This doesn't sound right to me and would like someone else's opinion. I'm going to lower it, 5-7, and don't want to have any drive line problems. Thanks for the help.