Rear end noise ?

[AR67GTX]

I had my 489 rear rebuilt a few weeks ago and got in on the road this weekend and unfortunately it has a howl in it. Richland 3.55 gears and an Auburn posi were installed with bearings, etc. I also cleaned up the axle housing and installed a new axle seals. I re-packed the original tapered bearings and left them in. This car doesn't have many miles on it. I set axle lash at .010 inch. The posi additive from Auburn was added.

I haven't been able to duplicate the howl with it running on jack stands. On the road from about 1500 to slightly above 2000 (35 - 50 mph I guess as I haven't recalibrated the speedo) running on fairly level road with a feathered throttle to hold speed it starts a howl. Let off the gas and it stops. Give it gas to accelerate and it stops.

Increase my Speed higher and it seems to quit or at least lessen to where it's masked by road noise. I don't think it's making noise at lower speed but this old Torqueflight transmission does a lot of whinning as it downshifts at low speed.

No noise around corners after driving the axle ends are cool to the touch so I'm discounting the bearings.

Apparently it's the set up of the gears but in googling it seems that howling while accelerating or while decelerating is more the norm - one the gear pattern is too deep and the other it's too shallow. I haven't really found any instances of howling with a light, feathered throttle to just hold speed. The guy who rebuilt it is a long time mechanic who builds cars and does some racing. He's built a lot of Mopar rear ends for the Mopar community around here.

The pinion nut was tight when I put a wrench on it yesterday.

Anything I could check before calling him? I've probably put about 10 miles on the car checking it out.

Thanks

 

[miller]

The guy that built my gears said I'd probably have a little whine. As long as not too bad, like your's, probably just live with it. Only fix is to bust it down, and start over. All in the tooth pattern.

 

[Yatzee]

No need for concern. I had a new set of Richmonds put in my 489 and had the same issue. It's probably OK and the noise is the nature of the latest Richmond gears - their **** and poorly made. Tried a set of Yukon's and the noise was not present anymore. I was told that the noise from the Richmond's would go away with time but my patience wore out. I have heard it rumoured that you can lightly grind the tips of the gears to correct this issue but changing them seems like the real solution. When I finally got around to yanking them, the wear pattern was perfect so I knew the issue was the grind on the gears that made them noisey and no adjustment in the world would quiet the differential.

 

[747mopar]

I don't know, I rebuilt a 489 using Richmond gears and bearing and not so much as the slightest amount of whine. I can say that I farted with it until I had it all set spot on and had a nearly perfect contact pattern so I don't really buy into it being normal.... maybe from a so so effort? Setting up gears takes a lot of patience.

 

[AR67GTX]

This is definitely not a whine - more of a howl - but only at light throttle steady cruise. I can accelerate or decelerate out of it. I know my rear u-joint is suspect - it has slight lateral play when in the yoke before I tighten the straps. Apparently under dimension I guess. I centered it as best I could before driving. My mechanic suggested going ahead and replace the u-joint and if it still makes noise to pull it out and bring back to him. He said after inspecting it he may just have to get another gear set. At least I should be able to pull it out faster this time. Probably pull the whole rear again - laying under the car and trying to wrestle that 60 - 70 lb chunk out while covered in lube doesn't much appeal to me.

 

[Banzaiii67]

I have the exact same "whirl" as I call it on light acceleration above 50mph, goes away with heavy throttle and no throttle. I can't remember what my manufucture my ring and pinion are (Motive or USA Gear) but it's a Doctor Diff 489 case 3.73 gear. I have also re-sleeved and balanced my driveshaft and have all new u-joints.

 

[747mopar]

This is definitely not a whine - more of a howl - but only at light throttle steady cruise. I can accelerate or decelerate out of it. I know my rear u-joint is suspect - it has slight lateral play when in the yoke before I tighten the straps. Apparently under dimension I guess. I centered it as best I could before driving. My mechanic suggested going ahead and replace the u-joint and if it still makes noise to pull it out and bring back to him. He said after inspecting it he may just have to get another gear set. At least I should be able to pull it out faster this time. Probably pull the whole rear again - laying under the car and trying to wrestle that 60 - 70 lb chunk out while covered in lube doesn't much appeal to me.

Slight movement in the U Joint can be caused by incorrect thickness C clips, usually that won't make any noise but will allow a slight vibration as the shaft spins off center. Check your clips.

 

[AR67GTX]

Slight movement in the U Joint can be caused by incorrect thickness C clips, usually that won't make any noise but will allow a slight vibration as the shaft spins off center. Check your clips.

A cap fell off when I was putting the driveshaft in and I thought all the rollers were fine and put it on and installed the caps. When I was breaking the rear in on jackstands I noticed it was wobbling so I pulled the u-joint back apart and found a roller bearing in the end. Fixed that back and re-installed and noticed play in the yoke which I did the best to center. Haven't checked in the ends with clips to see if it has any looseness. But I'll just replace it.

Not wanting to live with this. This car is a full power and air cruiser and I spend to much time cruising at light throttle.

 

[moper]

No manufacturer or ratio of gears are ever inherrently noisy. It's always the setup. One can be close and it be noisy, but never fail. Like 747 I'm very careful on setting them and the pattern has to be perfect. It takes time. Sometimes a lot of time making sure the ring gear is perfectly flat on the carrier, the pinion preload is right at the right depth and the right backlash.
If it does it at light throttle cruise, IMO, it's the pinion bearings. they are loaded under coast or acceleration. Unloaded at light throttle. The down side is, if it's them, it may have hurt the gears.
Did he tell you how to properly break them in? I'd bring it back to him. It sounds like it's close - but not right.

 

[AR67GTX]

He asked me to run 90-140 lube, set it on jack stands and run for about 30 minutes to break in and set the axle lash at .008 inch - all of which I did except my lash ended up at .010 and I quit there. I'll have him look at the pinion bearings.

Thanks

 

[747mopar]

I just drive it for break in with no hard acceleration. I still think you might have the wrong thickness C clips, you shouldn't have been able to get the universal on the yoke with a needle in the bottom of the cup unless you really forced it. Good luck

 

[Cranky]

I never ever break in gears on jack stands....here's what Richmond says to do.

A new ring and pinion installation, especially a high
numeric ratio with new bearings, can cause an excessive
heat buildup in the rear end and cause softening of the
gear teeth and bearings if a break in is not performed.
Street vehicles should be driven at normal street driving
speed for approximately 10 miles, then stop and let cool for
30 minutes. Do this 2 to 3 times.

http://www.richmondgear.com/pdf/cat-33.pdf

 

[Ron H]

I ran into a buzz saw having my 742 reblt (3:23 to 3:55) 1st guy was accustomed to Ford/GM rears and thought he could do it...not. He installed complete overhaul kit. After just a few miles driving my new Yukon R&P set was likely trashed. This was confirmed after another so called well reputed shop thought they could re-adjust the rear by light grinding on the gear ends and then was adjusted too loose. Result? A poor job I paid a good price for. This shop messed up a few other things as well. Hard to believe they were featured in Hot Rod mag. 3rd attempt was a buddy having the smarts, tools, and patience (a lot of the latter) to ensure all set within spec's. Result is a pretty quiet rear though hear some subtle whine but not sure if it could be tranny noise and being a ragtop I guess you hear more. Talking with several people about rear gears if they make noise they'll stay that way; wishful thinking I gathered that a rear end will break in and run quieter..

 

[AR67GTX]

I went ahead and bought a new Moog u-joint to install. Kind of a nifty piece with a grease zert in the end of one cap instead of in the body. Hard to understand how these differentials are so touchy to set up and break in is so critical - how did Chrysler ever manage to assemble these things and get them out the door and through customer test drives and hot foot owners without a high incidence of failures or noise complaints??

 

[AR67GTX]

Had a heck of a time replacing the u-joint at the diff. Apparently the trunnion cap size in the differential yoke is slightly larger than the one in the driveshaft. Plus the driveshaft yoke used external clips and the diff yoke uses inner clips. Took 2 u-joints to make up one that worked.

But - didn't make any difference on the noise and I pulled the differential out today and will take it back over to the mechanic Monday.

Anyone make anything of these tooth patterns - probably about 25 to 30 miles on them.