has anyone had any past experience with the rear propshaft causing a vibration under load, and at a steady highway speed? all u-joints are good, and the double cardan is in good order...but i am questioning slip center section of the driveshaft...would a little bit of play in this cause an out of phase condition? and i mean "little bit" of play...my bronco's a '95, if that helps...

 

all ive ever heard about that slip joint is that when it starts to go dry remove and re grease i guess they are real touchy when it comes to the amount of grease on them becouse then it cant slide like it needs to . i would check the blue coating that is on the splines as if it is worn off it will couse slop and check your u joints again mine was just a little sloppy and got some vibration hope this helps

 

i had the driveshaft completely out, and thuroughly checked the u-joints...guess i'll take it out again and check the splines a little closer...thanks ...

 

If your wheels are worn wrong(travled a long distance with low air pressure and cause un even tire wear) can cause a similar vibration.

 

The pinion nut has also been known to be a source of rear driveline troubles. Believe it or not they are known to work loose! Might check that before putting the rear DS back in too. The "fun" part about this whole problem is that the torque spec for the pinion nut that most manuals and spec sheets provide is a pre-load spec and then a final spec that should ONLY be used after installing new bearings. Makes retorquing without replacing the bearings difficult but not impossible..

 

already been down that road...i run BFG KO series all-terrains 31x10.5's that are meticulously rotated & balanced...i have found them to wear very descently with the twin I-beam front...it had goodyear wrangler ats's when i bought it...it developed vibration then, but it was steady at highway speeds only...it ended up that one of the goodyears had a broken belt inside it...

 

i'll definately have to check that...never came across that before...i suppose if that is the problem, installing a new crush sleeve would not be too big of a deal...there should be a pinion preload spec using the original bearings...lol, i guess it would be nice if that was the problem...when i inspected the rear brakes last, i seen an axle seal that was starting to seep...i could get it all done in one shot, lol...