Just another Differential harmony thread. Might as well move along.

My dad has a 65 Mustang. Bought it new. Has over 300 thousand miles on it. Every 65 Mustang whines in reverse. Didnt seem to hurt sales, doesn't seem to hurt resale. Never blew up. Sometimes mechanical things make noise and it is just normal.

 

Sometimes mechanical things make noise and it's not normal as well.

It's all speculative right now so you might as well just drive it

 

I think most Reverse Gears in Manuals have a whine to them. The issue on the Rear End Whine is that if it were a normal mechanical thing then they would all do it and these are hit and miss so it cannot be normal.

 

Yes, but just because you don't like it doesn't make it not normal.

 

Maybe its not hit and miss. Maybe some people just notice it more than others.

 

I know you traded for your new one, did both trucks do it? Some of the ones I heard on Youtube are screaming loud and it would be impossible not to notice.

 

Good point.

They all do that.

I just sold a subaru with a whistle that I couldn't track down. Sounded like a turbo at higher RPMs. I googled the the tar out of it and narrowed it down to a dozen possible reason and said the hell with it. Seems like everyone had the issue.

And that's what I told the guy I sold it to. It actually was quieter after I replaced one of the cats so I assume the other one was doing it to but the OBD2 smog test only check the one with sensors...

 

No, I said that earlier. Thats why I wonder if its the locker.

 

That would suck. Maybe/hopefully a different issue.

My hope is my noise doesn't get louder

 

Unfortunately, some of the guys described it as they do get louder as time goes on and others said it stayed about the same, i just think it is hit or miss with them.

 

I installed 5:1 gears in my '85 tcase which required grinding out clearance for the larger gear. I tried to do it with the least amount of grinding as I could and when I free wheeled it by hand it was ok. After putting the whole thing back together and reinstalling it on my truck, it made a very similar sound. Still does a little bit.

Which I attributed to the gear carving out the rest of the clearance it needed . Sucker ran hot for a long while.

I don't know if it's related or not.

I also did my own rear diff (5.29 w/Detroit) right around the same time so could also be that...

 

Also it was super loud but is now...less loud (still loud just less).

 

I have Amsoil 75w90 severe gear in mine, no howl so far from 0-100 mph...hope it stays that way.....automatic 2.7 liter 4 banger utility access cab, I changed mi e right around 1200 miles I believe. I actually never noticed it before that though.

 

Nice. How many miles?

 

I have about 3000 miles on it now , so far...so good, I will be sure to keep you all posted if I hear it.

 

To me it sounds like a loud tuning fork. Kinda.

At least on my truck.

 

Ok, at least I know what to listen for, is it a high pitch sound all the time, or just when feathering or coasting, I was on my way back from Harbor Freight yesterday and was on a straight toll road I376 here in Pittsburgh and got it up to about 105 mph , didnt hear anything like a tuning fork, but the wind on my AVS stick on window deflectors I could hear.

 

O.K. one of those guys in the Utubes was REAL loud and doesn't sound anything like what mine sounds like. Id agree that is a problem. One guys sounds like mine, just a slight howl, and one guy I couldn't hear it at all. He even gave time stamps when it was posed to be doing it.

 

Going way Off Topic with nothing to do with this thread, but about 25 or 30 years ago I was going about 90 or 100 thru the Liberty Tunnels and then headlights suddenly were gaining on my insanely fast and then a Grand National passed me like I was standing still along with about 4 or 5 cop cars.

 

I only hear it when when I'm feathering the gas pedal enough that I'm coasting in the slack of the drive train. Not pushing the ring gear and not coasting against the back side. It's like the tweener area. Or it taint one or the other.

Also perfect pitch is at about 55