Hello Everyone, seeing as though there are many lifted F-150s around case in point the many on this site, I figure you all can help me with my conundrum.....

I have a 97 F-150 2wd with a 3.5" spindle lift and 2" spacer for a total of approx 5" suspension lift with 4" blocks in rear. Truck sits fine. I am running 4.88's in the rear. The issue I am running into is that I am now feeling a driveline vibration at approx 60-70mph which is about 2500-3000 rpm. This vibration caused the drive shaft to break the tailhousing off the tranny and of course leave me stranded. I have had the tranny replaced and even put new u-joints on both ends of the driveshaft and the vibration still persists. As it is still the factory driveshaft, I am assuming it is ok as for being balanced and I am thinking that the issue is one or two things (maybe a combination of both):

1) Driveline angle too aggressive, though I see many people with drivelines that look much more aggressive, but I need to measure the angle to know for sure

2) Due to the lift is it possible that the driveshaft yoke would not be sitting far enough into the tail housing of the tranny?

With all the lift kits etc... around I am surprised that I don't see this issue more often. Am I on the right path? Does anyone with a 97-2003 or similar model with a lift have this issue or have you experienced the issue?

Any other thoughts are greatly appreciated. As I am needing to pick up the tranny and install it again I cannot measure driveline angle just yet.

Thanks for any help you can offer!

 

Sounds like you may need shims to adjust your pinion angle.