What is this noise

Blown351gt

New Member
Original poster
Joined
Oct 29, 2019
Messages
10
Location
Oakdale ca
This might be hard to hear but this is a video of an odd worrying noise whenever I get on the gas. If you listen closely you can here me get on the gas and let of the gas. It seems to only happen above 20mph but only makes this noise under load and seems to be worst in third gear. I just can’t pinpoint where it is coming from. I’ll jack it up this weekend and see if I can pin point it, I’m thinking pinion bearing starting to go but new to the Jeep scene so just trying to figure it out. Any suggestions?

 
It could be a bearing, but to me that also sounds like an exhaust leak.

I'd say it's time to drop the transfer case skid and inspect.
 
The only reason why I’m thinking it is something other than a bearing is it only happens when accelerating. It does not make the sound when decelerating. It almost sounds like it’s coming from the transmission but just can’t tell. I’ll start with the easiest first and have a buddy give it gas when it’s on the lift this weekend
 
That's true. In that case I think you're probably right and it is probably bearing related.
 
Pull the front shaft . U joints can scream .
 
Tough to hear, but I agree that it sounds like a bearing. The fact that it only makes noise when acclerating is because that is when the bearing is seeing some load. It unloads when you let off the gas, so you don't hear it. So could be transmission, or rear end related. Have someone sit in the back and when it is happening to see if it's location can be better pinpointed. Another thing to try is carefully rocking the Jeep back and forth as you drive. If the groan comes and goes like that, it will kind of point to being an axle shaft bearing. The good news is that it is pretty quiet at this point. If nothing else, odds are that it will get much louder long before it fails all together, so it's location should become more apparent. I drove home to Chicago from California with a pinion bearing that was dying, and by the time I got home, it was really singing, but made the trip, and a few more days back and forth to work just fine. One good thing about the old tech in our Jeeps is that they will take a lot of abuse without failing catastrophically. :)