Rear end whine

[Skytrooper]

I have a 71 charger with a 8 3/4 and 3.23 gears. It whines like a 5 year old in a toy store. Is that normal ? I mean I get that it physically spins faster and that therefore could possibly make more noise.

 

[Big Bad Dad]

My Dana 60 got pretty whiney at 145K miles. New bearings fixed it right up. And I mean pinion and carrier bearings inside as well as just wheel bearings.

 

[Don Frelier]

I have a 71 charger with a 8 3/4 and 3.23 gears. It whines like a 5 year old in a toy store. Is that normal ? I mean I get that it physically spins faster and that therefore could possibly make more noise.

Is it louder at a certain speed or does it just keep getting louder the faster you go?
There is gear oil in it right???

 

[tonysrt]

I had a guy set up my 8 3/4 rear after I put in sure grip. Put it in the car and hummed like crazy. Brought it back and he said ring and pinion were bad. Put new one in and hum was gone. I knew it wasn't axle bearings because it was all new from Dr. Diff and they could be checked.

 

[Project66]

My guess is that it's an issue with the gears. Is your diff oil level good? I just replaced my rear bearings and those sort of rumbled and roared when they went bad, no whining. Now that I replaced the bearings (thank you Doc Diff!), all is quiet at the rear of the car, still no whining.

 

[AR67GTX]

I’m not sure if it holds true for needle bearings but my wife had an Audi that developed a whine turning corners that was a bad bearing. Corners put more load on the outside turn bearing and created noise. Does the whine stop when you let off the gas or accelerate hard?

 

[Macdon221]

My 68 8 3/4 sure grip 741 case used to wine like that...but only in a 10-15 mile per hour band around 50mph, and only with power applied. Let off the gas and it would quiet right up. Took out the gears, new clutches, set it all up...no change. The next season I dismantled it all again but put in new pinion bearings this time from dr diff. Set it all up again same as before...and silent. Been working perfect ever since.

 

[Skytrooper]

There is gear oil in it right???

Yup, plenty of gear lube, and it is pretty clean.

I am continuing my investigation. Also doing a basic alignment. Then I can take it back on the road and try to determine when and where it seems to come in.

 

[WileE]

You could usually hear the difference whether it's a ring-pinion setup, or worn bearing(s). "Whine".. I've associated with ring/pinion engagement. But, I prefer beer myself.

 

[Don Frelier]

Yup, plenty of gear lube, and it is pretty clean.

I am continuing my investigation. Also doing a basic alignment. Then I can take it back on the road and try to determine when and where it seems to come in.

Okay is it a 489 case?
Otherwise you can pull the yoke and check the pinion bearing. It would cost you a seal.

 

[Skytrooper]

Yes, it is a 489 case. I drove it today and it really didn't sound too bad. It could be a lot of road noise due to no insulation. I did fix the alignment...it was toed in really bad ( 5 inches) Yikes !

 

[Don Frelier]

You mean 0.5 "?
I don't think 5" is possible the tires would squeal horribly

 

[Bill M]

check your axle end play if it still factory.

 

[Skytrooper]

You mean 0.5 "?
I don't think 5" is possible the tires would squeal horribly

Nope 5.0 inches total. I noticed when driving it around the block the other day that it was leaving tire marks on the road. I knew none of the wheels were locked up, so I did and alignment check this morning. I put a 4 foot straight edge across the wheels and made a mark 3 feet in front of, and 3 feet behind each front wheel. I then snapped a chalk line parallel to the body and measured those points. The fronts points were 65.5 inches, the rear points were 70.5 inches.

It drives better now and possibly some of the noise was coming from the front tires.

 

[AR67GTX]

Yes, it should drive much better, and quieter.

 

[Rebelrouser]

On a test drive, if the noise gets louder the faster you go and remains when you slip it into neutral and coast down, the issue is most likely bearings, also if the noise changes when you gently whip the wheel back and forth it is most likely axle or differential side bearings. If the noise only occurs at a certain speed and while making the noise you can play with the throttle and change the tone, the ring and pinion are worn and need replaced. If the root cause of the problem is a worn and loose pinion bearing and it has been driven long enough the loose bearings will take out the ring and pinion as well.

 

[Skytrooper]

Wow, good to know ! I will try those on todays test flight

 

[Skytrooper]

Of course, my luck has struck again. Started the car and let it come up to operating temp., go to drive it....no gears. Nothing in any position. Everything is all connected underneath. Plenty of fluid. No leaks. Transmission has maybe 25 miles since it was rebuilt.
No sign of impending issue. Driving fine yesterday and last night...today nothing.

I just walked away.

 

[oldkimmer]

Try putting it in neutral to circulate the trans fluid. Some have what’s called Morning Sickness on the first start of the day. It’s actually the torque converter draining back into the pan. Kim