semlin
curmudgeon
spent some time working on my friend's 91 today. took apart his driveshafts. Interesting to note that in the 91 FSM the driveshaft illustration shows both driveshafts "in phase" (e.g. yoke are parallel). Apparently the out of phase front drive shaft rule applies only to the 93 onward trucks. I wonder if this is because of some subtle difference in the driveshaft alignment or if they simply had not thought of it in 1991. The angle looks the same. anyway both his driveshafts were at 45 degree angles and setting them both in phase eliminated his 55mph vibration