I have a 95 Bronco with the standard rear axle which I understand is the Ford 8.8. This axle came off of my 96 during a long process of trying to isolate down a vibration on the 96 (I switched axles during a time when I wasn't really driving the 95). So, the 95 has the "vibrating" axle (it wasn't vibrating until I put this axle on). The vibration starts around 55 and gets worse with higher speed. I've switched tires and brake drums with the other Bronco (all "know good") and it didn't change anything. Jacked up the rear, put it on heavy duty stands and the wife ran it up while I watched. Tire wobble looks non-existent. However, the companion flange looks to have some "forward and back" wobble, as if it were bent. It doesn't make any noise and, after disconnecting the drive shaft, I can't feel any "up/down" play (which would seem likely if the bearing were bad).

So, the question: is it possible that just the companion flange is bent or is it most likely that the pinion shaft, maybe forward of the bearing is what's actually bent (or maybe both)? If it's just the companion flange, is it possible that it could be changed relatively easily? I got a quote on about $500 (minimum) to go in and replace bearings (over the phone, they didn't look at it and at that time I wasn't thinking it could be the flange bent) if that were the culprit. Seems like I could get a decent used axle for less than that (one yard quoted $250). I am getting good at changing these out!

Thanks,
Biederboat