nesok

I can understand that an ignition problem could cause issues like this, except when the car is in FWD, it runs and drives fine. Has been for days. But as soon as you pull out the FWD fuse, the vibration starts. I'm really bothered by the amount of play in the rear diff so I think I'll try some new bushings on the mount and see how it goes.

Maybe check coil for corrosion on the plug wire contacts.

A few months old. We also put in a new ball joint on the driver's side and brakes with rotors before the alignment about a month ago. Whoever did the alignment said there was a rear bearing going bad but I'll be damned if I can find which one. Of course, the pvc tree was cracked and leaking and the same guy said the oil was coming from a blown head gasket that he offered to fix for $2200. So he may have felt the beginning of the mystery vibration and assumed it was a bearing during his test drive?

Have you checked the main power fuse (80 amp I think) in the engine compartment? I had one in an 02 Outback look good but had actually broken on one of the legs before...

Hey guys, been lurking for a while and usually get my answers from searching through the threads, but I'm pretty stumped right now so here goes my story... 1990 AWD Legacy, automatic New tires, alignment, struts. No MIL and it does function. No binding while cornering. Is my niece's car, she drives like a grandma in the mountains of the front range. Mostly pavement though some dirt roads. I went out of town and she said her car wouldn't accelerate over 40mph. I get back and the rear diff is PUKING 80-90. So I replace it with a good, used unit. I also replaced both rear axles because one was binding, and one looked horrible. She drives for a few days and then states car won't go over 20mph. I drive it and it's fine. Next day I drive it again and the car is bucking and vibrating like the torque converter is locking and unlocking randomly. Weird. So I toss in a tranny, still does it. Next day, nothing. Day after that, as soon as the car accelerates to 20mph horrible vibrations. Take my foot off the gas and it instantly stops. The car will happily roll to 50mph as long as I'm not accelerating. Decelerating is fine. Next day, drives like nothing is amiss for 20 miles. (what the...???) I put a fuse in the FWD holder (yeah, I should have tried that first!) and the vibration almost disappears. Pulled out the prop shaft (even though I eyeballed it during the tranny and diff replacement) and I can faintly hear needles moving in the carrier when I spin it. But there's no play and u-joints are good... so after throwing some time consuming darts I don't want to just throw a prop shaft at it. I also noticed the rear diff has a lot of movement when I was getting it on the stands, but I don't think it's excessive. So with the car in the air I have my son accelerate and decelerate while scouring the drive train for movement but don't see anything alarming. I'm guessing there isn't enough load with the wheels in the air. Ideas? Thoughts? I'm kind of at a loss and am pretty darn frustrated right now. Any input would probably help out at this point.