UPDATE: growling noise heard coming from driveline when I let off gas/coast

[resq302]

Ok, I just came back from the Hershey AACA show and to and from the show, I noticed a clunk and then a growling noise.  The clunk happens when I give it gas from a coast or from letting off the clutch.  The growl comes after I take my foot off the gas and start to coast.  I put the car up on my lift and checked the U-joints and they have no play in them so they are good.  The rear (third member) was rebuilt last year and seems to be no play in the pinion yoke.  What I did find was play at the tailshaft area of the trans where the slip yoke goes into the trans output shaft.  Could this be the clunking noise and growling noise that I am starting to hear?  I have heard that there is a brass bushing in the tail shaft that sometimes wears, could this be it?  Also, I have a spare trans laying around my house but the syncros are bad.  How difficult is it to rebuild a manual trans?  Is any special tools needed?  Would I need a press or any special equipment?

My charger is a 69 Charger with a 383 4 bbl HP motor and the A-833 4 spd tranny.  Any help would be appreciated as I am going to be driving my car to another show this coming Sunday and the noise and clunking sound concerns me.

Thanks in advance,

Brian

[zstalker]

http://www.unclewebster.com/lc/bus/625/
http://www.differentials.com/diagnose.html
a couple resources I found...

[deputycrawford]

Also, put it in gear and slightly power brake it. Have someone look under the hood and under the car to see if the trans is moving around under load. I just found my trans mount torn in half.

[resq302]

Deputy,

I did the power brake test today and my dad said the trans moved very little.  So the trans mount is good.

Brian

[deputycrawford]

Then hammer down driver.

[resq302]

The problem is still there so I have to find out what it is cause that noise really doesnt sound good.  The growling noise almost sounds like a very low pitched grinding of gears like someone cant find third gear.     That ER, ER, ER noise only very low pitched like someone trying to start a car with an almost dead battery.

[deputycrawford]

You know, I have kinda the same low growl from around 70 MPH to 90 MPH. It goes away after that and my trap speeds are around 105 MPH. It is a slow rhythmic growl. I hate it and can't finger it out.

[resq302]

I think I know the noise you are talking about with that as I have something similar but this is low speeds around 40 -50 mph.  The noise at the higher speeds I think is the fan on the engine as I do not have a clutch type fan and think it is making a noise similar to a plane getting really to take off.

This noise I am having now is definitely somewhere in the drive line though.

[LeesRT]

If it were me, I'd start by removing the driveline and check things like pinion bearing (spin by hand to make sure if feels ok), check splines on end of driveline where it meets with trans, check all trans and engine mounts, check to make sure your clutch hasn't come apart.  If all of this looks ok, then more troubleshooting will need to be done.

[LeesRT]

Driveline balance may also be something to consider.

[resq302]

Ok, just had the car up on jack stands with the car idling with first gear engaged.  No noise present aside from the whirring of the gears which can be expected from the rear and trans.  One thing I did notice though is that the rear center chunk got REALLY hot to the point I could probably burn my hand if I left it there long enough.  Is the rear axle center section supposed to get this hot?

[68 RT]

Sounds Like your rear end is going out. Should not get hot enough to burn your hand. See if your gear oil is burnt. Could be a carrier bearing bad too. I had a fullsize blazer starting to do this. Lasted maybe 500 more mile till it ate its self.

[deputycrawford]

My rear 4.10 gear is new. It has been taken out and set up a second time. All specs showed great. I did notice the trip to the Chrysler Classic I had to back out of it because it started to smell like hot gear oil. I can't seem to find my growl either. I guess I will have to put another rear end pic together. Don't know yet.

[resq302]

Well, comparative speakingly, I  felt the muffler and then felt the center chunk of the rear axle.  The muffler was cool while the third member was still quite warm.  I talked to the person who rebuilt my third member and he said he will look at it after I take it out and bring it to him.  He figures from lack of use, the one bearing seized up or has a lot of rust on it.  I did pull the filler plug out and some gear oil started leaking out so I know it was full enough.  The color of the gear oil is semi transparent with a tint of dark brown.  Also, very metalicy when you hold the fluid up to a light when it is running down the container.  Granted, I know it will have some metallic look to it as the gears are wearing as I have always seen this but for some reason, this looked to be more metalicy than normal.

[TylerCharger69]

I want to lean toward the rear end too.....You don't specify,  but since this is a 4-speed car, I'm going under the assumption that this is a Sure-Grip rear end.   Did you put the proper additive in it  and not just the gear lube itself???

[resq302]

Yes this is a Sure grip rear.  I guess I did forget to mention it in the original post.  I remember for a fact that I added that little bottle of additive when I put the original fluid in.  With any luck, I will get home from the show on this coming Sunday early and I can pull the third member and see what I have.

One thing I have noticed also is that when the clutch is pushed in, the noise goes away.  Does that mean anything?

[TylerCharger69]

Let us know the consensus  when you return!!!

[resq302]

Better yet, I will try to post pics

[Just 6T9 CHGR]

Are you sure the clutch is fully releasing?   It might be a simple clutch adjustment or maybe the throwout bearing making noise?   Not up on my 4-speed stuff but worth a check

[resq302]

Chris, I took the charger to a tranny shop and they said the noise is definitely coming from the rear, not inside the trans like I had originally thought.  He checked the throw out bearing for noise and said the noise it is making is typical Mopar and nothing to be concerned about.  The noise is not constant either and only does it sometimes.

[resq302]

pic of gear oil caught from when I removed the fill plug.  Gear oil is only one year old and has the limited slip additive.

[Just 6T9 CHGR]

Looks fairly normal to me......run it till it blows

[resq302]

Id rather fix a small problem now than have to replace the entire third member and my axles due to my rear grenading.

[deputycrawford]

Burnies until it bangs.....lol..It sounds like me. I drive it until it breaks. Then I fix it.

[resq302]

If I had money laying around, I would say sure, but with the radial tires not mounted on my other rims yet and the repro bias plys costing $135 each, I can't afford new bias plys or an entire new third member.  Maybe if I wasn't married or expecting a child soon, I would be able to do that.

[resq302]

Well,  I just had a chance to pull the axles and the third member yesterday.  Wasn't a pretty sight.   Very dark shiny gear oil came out when I pulled the third member.  When I pulled the right axle out, I noticed a primer dark gray color on the hub side of the bearings.  Keep in mind I rebuilt the rear last year and installed Green bearings which are sealed.  After I got the axle totally out, I noticed that the right side had play in the bearing.  After removing and checking the driverside, I knew the right side needed to be replaced as the left side had minimal play.  It gets worse....  after I got the third member out, I noticed the teeth were quite shiny.  None of the teeth looked to be broken or chipped from what I could see on the ring or pinion.  However, when I was cleaning up the bottom part of the axle banjo, using a magnet I picked up a lot of large slivers / chunks of metal.  I called up the local trans shop that rebuilds differentials and brought it to him and they inspected it.  They agreed that my right bearing was on its way out and I should replace it while it was out.  I was already one step ahead of him and had them on the way.  As for the differential, he looked at it and immediately said there was not enough play in it.  He said there should be about .10 thousands of play where mine hardly had any.  So that explains the growling noise as he said the rear was set up too tight.  He actually said they see a lot of them set up this way and come in with the same problem.  Rebuilders who do not do diffs that often usually think setting it up a little tigher is better as it will "break in".  Not the case.  The only think that was breaking in my differentials was the gears. 

After all was said and done, they said to come back when I have my parts and they would be happy to help me out with setting it up.  $400 in parts + $300 (guestimated) for labor = A HUGE HOLE IN MY WALLET! 

If I had let it go like some people have said I should and run it till it blows, I would have probaby would have had to replace the axles, bearings, axle housing, and basically everything.  As bad as it sounds, $700 now seems to be a lot better than spending over a thousand later on when I certainly wont have the money.

[resq302]

Here are some pics of the chunks / flakes of metal I picked up with a magnet.

[RECHRGD]

You stated earlier that you talked to the guy that "rebuilt your third member".  Doesn't he guarantee his work?  Sounds like the gear situation is his problem.  He should replace the gears for free IMO.   Bob

[resq302]

Bob, he said that it was probably the posi-unit (sure grip) unit self destructing.  If he just installed that last year and swapped it over from a 742 case, I can't see why it would go bad.  Someone correct me if I am wrong, but the sure grip units just "don't go bad by themselves".  I understand that the clutches on the 742 style sure grip wear but I can't see them causing all that metal chunks and stuff.