Automatic transmission, 1994 Jeep Cherokee, 200,000 miles.

My brother just had his oil changed at Time-It Lube. They checked a bunch of stuff (trans fluid, diff fluid, brake fluid, etc). It doesn't appear that they changed anything by looking at the invoice (other than the oil and filter), but still, they've been poking around.

Now it's making a weird grinding noise. I rode with him. It's definitely not the transmission making the sound, the differential, or the steering. It's coming from the engine bay, and towards the front. It sorta sounds like an oddly vibrating radiator fan, but it only makes it when he's on an incline, giving it ample gas to climb it- the engine is under more load. If he puts it in neutral and gases it, we're not hearing the sound (but he was gently gasing it...)

What do you think it is? It doesn't sound like heavy metal grinding. It sounds lighter than that. The tone of it is kind of a raspy straining groan sound, like you're on the toilet constipated. Can you think of something else it could be besides the radiator fan? I haven't really tried troubleshooting anything yet.

 

Check the lug bolts for the tires..... yeahI know, lug bolts??!? You might be surprised. If thats not it...I dunno.

 

check to see if they changed the weight of the oil. i'm just thinkin mabe the sound was there all along, but a thicker oil was used before to cover it up.

 

He had a mechanic look at it today. As I suspected, it is a problem with the radiator fan/shroud - and also the motor mounts. I mentioned that it makes the sound when the engine is under load (climbing an incline). When the engine torques (it's an in line 6, RWD so it doesn't rotate front to back, but side to side) it causes something to go out of whack and it makes the fan get raspy. The motor mounts are old, so they're allowing the engine to move a little too much. Why this problem has arisen right after an oil change - I'm not sure. Maybe the jeep is just sort of a house of cards, and they touched something that caused it "fall."

EDIT:
I could have sworn I started this thread in Off Topic. If I created it in General Tech, I didn't mean to. A Jeep Cherokee is off topic imo, and I'm sorry I'm taking up space in gen tech. Did a moderator switch it? I really don't remember putting this here.