High pitched whine at 65?

ScoobyCarolanNC

Active Member
Hey there. I’ve recently developed a high pitched whine that you start to hear around 60mph, crescendos around 65, and then kind of goes away. If I’m at 65 and take my foot off the throttle it goes away. Foot back on and it’s instantly back. I checked everything visually and it all looks good. Carrier bearing has a spacer and it’s tight. All the boots are ok on the driveshaft. East Coast Gear Supply recommends running 85/140 non-synthetic and I’ve been running it for a few thousand miles since I went up to 37s. Should I consider going back to stock oil weight to see if that’s it? I read on currie’s website that they recommend slightly overfilling a stock axle that’s had its pinion angle increased. Should I try that? Any ideas welcome.
 
Assuming you've re-geared, I'm gonna put my money on the fact that your pinion bearing is starting to go bad. If that's the case, no oil weight will fix that. Over filling a diff will only cause it to get pumped out at the breather. I personally would recommend that you take your Jeep back to the shop that did the work and have them give it a look - before it gets worse.
 
Assuming you've re-geared, I'm gonna put my money on the fact that your pinion bearing is starting to go bad. If that's the case, no oil weight will fix that. Over filling a diff will only cause it to get pumped out at the breather. I personally would recommend that you take your Jeep back to the shop that did the work and have them give it a look - before it gets worse.
Thanks Eddie, I'm actually not regeard. This is what I was afraid of, but I'll get it checked out. Thanks and happy new year!
 
Thanks Eddie, I'm actually not regeard. This is what I was afraid of, but I'll get it checked out. Thanks and happy new year!
Hmmm, okay then. Tracking down a gear whine can be difficult especially being that you only hear it when driving. Can you tell where you're hearing it the most? As in, if you put your ear to the cup holders, is it the loudest there?
 
OK the plot thickens. I dumped the diffs today even though its only been like 6000 miles. A good bit of fine metal on the drain plug magnet but nothing solid came out. Everything seems fine there.

On my test drives though I realized that yaw of the jeep affects it and it seems to get louder if my steering is a bit to the left. I've very sure it's the front end now. Maybe a wheel bearing? Any ideas?
 
What you see on the drain plug is normal. Being that the sound is related to steering, I have to wonder if maybe you're just hearing the electric steering pump.
 
While I know posting YouTube links is frowned upon, I uploaded an attempt to record the sound. You can’t hear it too well, but give it a listen and tell me what you think?

 
sounds like a hub, dust shield or brake wear clip that's come loose, had to deal with all those type squeals on the JKU - it was usually the hub

I'd raise the front end and hand rotate the tire while it's turned in the direction you hear it most (also check the hub), then remove the tire and hand rotate the hub, inspect the dust shield and brake clips
 
Says who?
This ^^^

That said, I can't say that I could really hear anything but then, my hearing is kind of bad. Is what I was supposed to hear only happening on decel? If so, I think I may have heard something and it reminded me of a pinion bearing going bad. Kinda like what we were hearing on the ACCUAIR JT.

It should be noted that there have been recalls regarding the JT rear drive shaft. I might have your dealership give it a look.
 
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