Sub. Outback: New drive shaft, got suuuuper loud a few days later

I just got my drive shaft replaced after waiting too long. Prior to the repair it was rattling, in the direction of the back right wheel. It would get a lot worse if I was carrying things in the back. Since the repair that has been totally fixed last week.

However, I made a long drive from Boston to Blue Hill, Maine, last weekend, where we drove around a lot and on the way back (I think that’s when it started) it began getting pretty loud at highway speeds – it sounds like an accelerating motorcycle – in the same vicinity as the old rattle.

I’m going to take it back to my mechanic and see what’s up but wanted to hear all of your thoughts too. The pater things its a u-bolt because I ignored the drive shaft problem (I am sorry! Do not shame me further than I have already been shamed) and I am hoping its just that my tires need alignment or similar and is not related to the drive shaft? I tested the drift last night and it did list to the right, but then this morning I tested again and it seemed fine.

Edit: I got an oil change this month, prior to the roadtrip and have another 2k miles to go until I am due for another.

Sounds like an accelerating motorcycle?? I’d suggest there is a hole in the exhaust pipe if that’s the side the exhaust pipe is on. In any event, take it back to the shop and have them check their work and for something new.

In the absence of better information, I can’t say if they are related.

The model year and mileage would help. More than likely it’s a wheel bearing. The axles have velocity joints not u-joints. It’s likely that your bad axle was replaced with a rebuilt axle, and it’s a possibility that the rebuilt axle is bad but not very. There is a center support bearing and u-joints on the drive shaft, but a bad u-joint would wobble and cause vibration more than sound like a motorbike. .An exhaust leak you could hear if the car is stationary. Have someone crawl under and listen.

The exhaust pipe must be removed to access the drive shaft, if new exhaust pipe gaskets were not installed you may now have an exhaust leak.

Thanks so much!

It’s an 05 outback with about 136k miles on it.

I also had the front break pads and the rear struts replaced at the same time, in interest of full information.

The noise is coming from the rear right side - correct? There isn’t much back there, so there is a limit to what can be making the noise: bearings, (rear) brakes, axle (shaft), or tire. your mechanic should be able to find the problem pretty easily.