So I've been trying to track down 2 issues I've been having with my 2005 AWD ever since my tranny blew up last year (which was replaced). I've had a number of drivetrain related issues since then. To summarize: I've replaced all 4 CV axles (front ones were clicking and the rears had play and seals were leaking so I replaced them too). I also replaced the center support bearing/bracket since the rubber donut was brittle and cracked. For each wheel, I've inspected all the ball joints and tie rods, and they all seem snug (no play in anything). The car also has 4 new tires. I also replaced whiny bearings in the viscous coupler.
Problem 1: Above 65 mph I have some vibration when accelerating, and it is prominent when going uphill. I cant tell where the vibration is coming from though. I suspect possibly the U joints on the drive shaft, and I will inspect them for play. Are there any other possible sources of a vibration? When I replaced the center support bracket/bearing, I kind of eyeballed it when reinstalling and have since been worried that its not aligned straight. Anything else I should inspect? If it is either the front or rear U joints on the drive shaft, where can i get replacements? The typical places (autozone, advance, NAPA, rockauto) dont seem to have direct fits. Does anybody have any part numbers or recommendations?
Problem 2: There is a prominent buzzing at high rpms. It sounds like a loose heat shield, but I've inspected all of them. I took the car back to AAMCO (they did the trans) and they said it is coming from the catalytic converter. If I accelerate to 3-4k rpms in park or neutral, I can reproduce the noise. I haven't verified it was the cat myself though since I can't listen underneath by myself while revving. My question is, what is the best solution for repairing or replacing the cat? Are there any cheaper options other than replacing the entire exhaust/cat, which can run in excess of $500? I was thinking of maybe looking for used exhaust parts, but I'm not sure how to go about doing that. Any advice? This may have to wait, at least until I solve the vibration issue.