Any ideas about rearend whine?

[MichaelRW]

The following is about a 1970 Charger R/T, stock 440 -4, 727, 3.55 rearend.

Have had some whining sound coming from the rear of the car for some time now. So early this summer I decided to take it into a shop to have it checked out. They put some sort of "listening" device in the car and determined the noise was coming from the rear wheel bearings and the rearend. At that time I had new rear wheel bearings installed and that lessened the noise somewhat.

But I was still getting a loud whine particularly when de-cellerating from about 40-45 mph. The shop said the ring & pinion bearing needed to be replaced. So Last week I took the car back in and had the r&p bearing replaced. They said the bearing was very worn. Now the noise is louder by a little bit but more noticeable upon acceleration from about 35-45 mph. There is still noise when de-cellerating. They said to drive it a little bit and see if the noise lessened. BTW, they have not presented me with a bill YET. I drove the car about 100 miles last Saturday and the noise stayed the same.

Please help. Any ideas? What should I do next.? Or is this typical of these rear ends?

[RD]

there is a break-in time, but I am not sure exactly how long it will take before the noise goes away.  CP or Ron will have a better idea, John_Kunkel will probably know also.  Sounds like a backlash problem.  Did you have the carrier bearings replaced, or just the pinion bearings?

[John_Kunkel]

A properly setup gearset should make no noise, even when new.

Either the gears are bad or the setup is off.

[MichaelRW]

Thanks to both of you. Your help is appreciated. I'm going to go talk to the shop now.

[Just 6T9 CHGR]

Aftermarket gear sets are a bit noisy.  Are these stock or aftermarket?

[MichaelRW]

It appears the gears are the factory originals with approx. 82,500 miles on them. The shop said they replaced the front & rear pinion  bearings and the carrier bearings. Their suggestion now is to replace the gears since the bearings did not solve the problem. They thought the bearings would have done the job but they didn't. They are going to compare the pricing on either replacing the gears with a gear kit or perhaps (if the price is right) to replace the whole 8 3/4 rearend with a new one. The owner of the shop said that sometimes the whole rearend can be less expensive than the gears and labor route. He said he was going to call Summit Racing and for prices and then get back to me in a couple days.

Comments are welcome.

[andy74]

i would check with another shop-if they are just tossing parts at it to see what cures the problem,they will cost you money.if the gears were screwed up,it would have been making that noise for a long time,how long did you drive it like that? i may be wrong,but ive seen cars with way more miles and no whine from the diff-may be the lash isnt set properly?gears shouldnt be noisy,and if you can hear it,there is a definite problem.

[MichaelRW]

i would check with another shop-if they are just tossing parts at it to see what cures the problem,they will cost you money.if the gears were screwed up,it would have been making that noise for a long time,how long did you drive it like that? i may be wrong,but ive seen cars with way more miles and no whine from the diff-may be the lash isnt set properly?gears shouldnt be noisy,and if you can hear it,there is a definite problem.

The rearend noise has been there since I bought the car which is about 1000 miles ago. The majority of the restoration was done last summer (2004) but I am now addressing some of the smaller things that bother me. When I started the restoration my plan was to just take it to a "driver" level car but my dang insistence on perfection just keeps making me want to do this extra then that extra. It never stops. New wood on the dash and a steering wheel restoration is next. Also, new A/C components.

[BrianShaughnessy]

Here's a couple links to help diagnose noise...   no, you really shouldn't have any noise but I guess that all depends.

http://www.randysringandpinion.com/content/technicalhelp/default.asp?pid=109
http://www.randysringandpinion.com/content/technicalhelp/default.asp?pid=110

An 8 3/4 has a pumpkin that has all the gears and bearings for the centersection and is fairly easy to swap out.
You can change your gears or upgrade a posi unit too... I guess it just depends what you want to do.  Complete rebuilt 489 pumpkins go for $950 at mancini's.

I'd put that money towards a Dana before I shoveled more into an 8 3/4 but that's me.

[MichaelRW]

I'd put that money towards a Dana before I shoveled more into an 8 3/4 but that's me.

Food for thought. Thanks.

[MichaelRW]

Here's a couple links to help diagnose noise...   no, you really shouldn't have any noise but I guess that all depends.

http://www.randysringandpinion.com/content/technicalhelp/default.asp?pid=109
http://www.randysringandpinion.com/content/technicalhelp/default.asp?pid=110

An 8 3/4 has a pumpkin that has all the gears and bearings for the centersection and is fairly easy to swap out.
You can change your gears or upgrade a posi unit too... I guess it just depends what you want to do.  Complete rebuilt 489 pumpkins go for $950 at mancini's.

I'd put that money towards a Dana before I shoveled more into an 8 3/4 but that's me.

Just finished reading the 2 tech sheets. The problem was described exactly as it is happening. "If the gears howl while accelerating over a certain speed range, but not all speeds, it's likely that the gears are worn due to lubrication failure or overloading".

[RD]

Here's a couple links to help diagnose noise...     no, you really shouldn't have any noise but I guess that all depends.

http://www.randysringandpinion.com/content/technicalhelp/default.asp?pid=109
http://www.randysringandpinion.com/content/technicalhelp/default.asp?pid=110

An 8 3/4 has a pumpkin that has all the gears and bearings for the centersection and is fairly easy to swap out.
You can change your gears or upgrade a posi unit too... I guess it just depends what you want to do.   Complete rebuilt 489 pumpkins go for $950 at mancini's.

I'd put that money towards a Dana before I shoveled more into an 8 3/4 but that's me.

Just finished reading the 2 tech sheets. The problem was described exactly as it is happening. "If the gears howl while accelerating over a certain speed range, but not all speeds, it's likely that the gears are worn due to lubrication failure or overloading".

I cannot believe the shop did not look for that in first place.  That would severly piss me off.  Well, I guess that is why I do my own stuff

[MichaelRW]

The shop thought the bearings would fix the problem without having to replace gears too. They said that if I wanted to replace the gears they would not charge the labor that would be duplicated to pull it apart again.

[cudaken]

 MichaelRW, sounds like the shop is trying to be fair with you. Been nices if they where right the first time, but they are trying to meet you half way.

                                      Cuda Ken