Round 2 with rear end rebuild

[AR67GTX]

This is round 2 of my rear end upgrade and rear axle noise in my 67 GTX.

First - since I'm getting kind of old and well practices at pulling the rear chuck out of this thing, I've developed a little carrier that secures to my jack for sliding it out and in, out and in, out and in, etc.

I was getting light-throttle howl when we first installed this. After pulling it back out I found the backlash had slipped considerably. The wear pattern looked good but only had a few miles on it. He tightened up the backlash and then I had light throttle howl and trailing throttle whine. Nothing I could hear under acceleration. We tried some Lucas gear supplement but since it was 90 weight all it did was increase the noise over the 140 I started with.

So now it's out again. The contact patterns still don't look terrible to my unpracticed eye. Backlash was about .0075 to .008 inch. It doesn't show up in the pictures very well, but the gear tooth contact on the deceleration side is running off the inside end of the teeth. It's visible in the middle picture or the second gear picture. I'm guess this is probably the source of the noise (?). I don't recall it looking like that before so possible tightening up the backlash caused it.

We have ordered another gear set. I'm suspicious that one of the replaced bearings could be the issue so I'm going to have him replace the pinion bearing. Or should I have him replace all of them again? Hoping we get it this time and Richmond will refund the first gear set but I have a feeling this is becoming a money pit - just throw money in.

 

[mopar 3 B]

I have read that noise is a common treat with Richmond Gear.

 

[AR67GTX]

They are Richmond gears. My guy says he has had good luck with them. My car may change his mind.

 

[multipleBs]

Hi AR67GTX:

I know you have an 8 3/4, but I ran Richmond 4.10 gears in a 8 1/4 that initially were howlers. I too found the backlash adjust hadn't been done properly. When I got it down to the .004-.006 range they were completely quiet and reliable. You have to preload the side bearing considerably before applying the locks for the adjustment to hold. Be sure to check the runout too, if it's too high, .004 at one point could cause a bind at some other point. I like to measure it in at least 8 spots approximately equally spaced. The carrier has to be spotlessly clean before mounting the ring gear to keep the runout down to .001

 

[snakeoil24]

Two things I would recommend.
1. have the machine shop mount he carrier in a lathe and check for run out.
2. use dana Gear sets.

 

[moper]

Nothing wrong with Richmond, Yukon, Strange/US Gear, Motive... etc etc etc. Looking at the coast side it looks like the gear isn't seated right on the carrier. Is the backlash exactly the same at all positions around the ring gear? Or is it off even .0005"? When you reassembled it and set the backlash - which side did you tighten first?

 

[snakeoil24]

If the ring gear is not seating properly check to make sure it's not out of round. Dana is still the best for the money. Yes Motive is also really good. Check the simple things first. The pattern on the ring gear is not clear. Looks like Vibration. If you dont want to spin on a lathe at least mount a dial on the center section and check for run out on edge of ring gear interface..

 

[dvw]

Looks like it needs a little more pinion shim to me. The drive pattern is running off the face (top) of the tooth. It's right at the edge of the chamfer.
Doug

 

[Madmopars]

I agree with DVW, looks like it needs more pinion shim.

 

[moper]

While the placement of the contact patch is a little off, it's the varying lengths of the coast side pattern that has me thinking the ring gear isn't seated on the carrier right, or the carrier side bearings are not preloaded properly. The outer dimensions of any gearset are not terribly important. The pinion is firmly held. So if the backlash readings varying, something's wrong with the carrier in the case, or the ring gear on the carrier. You need to tighten the pass side adjuster last when you are setting backlash.

 

[AR67GTX]

I haven't checked in for a few days. It's over at the mechanics now getting a new gear set. It's a 489 case and I asked if he was using a crush sleeve eliminator sleeve kit and he said no - he preferred working with the crush sleeves. I did not take enough good backlash measurements and record them, to determine how consistent it was all around the ring gear. It seemed to be pretty consistent but could have varied .0005 inch. I did tell him to replace the pinion bearing again as something was setting up a concrete mixer rumble when I listened to it running on jack stands. When I get it back I'll take some readings on backlash.

 

[multipleBs]

When running on jack stands with the rear suspension hanging the pinion angle will be far from zero degrees, often a vibration will be present that wouldn't be there on the road. It shouldn't rumble as bad as your description but if there is a vibration it could cause some noise. 5/10000s is well within spec for runout. Some prefer the 489 case for the slightly larger pinion stem, others like the 742 for the type of sure-grip, clutch packs instead of cone clutches. They both are sturdy pieces unless you're running a four speed and serious torque (well over 500 lb ft). Many will run to the Dana 60 at the first sign of trouble with an 8 3/4 but in most cases on a street driven only car it's overkill. Personally I like the removable center section as it's easier to work on. I have done quite a few rear axle jobs under the car on other axles, the 8 3/4 is a pleasure to work on in comparison. Your carrier idea is a good one, I do something similar with a transmission jack, used to just toss it in and out by hand but it feels a lot heavier these days.

 

[AR67GTX]

When running on jack stands with the rear suspension hanging the pinion angle will be far from zero degrees, often a vibration will be present that wouldn't be there on the road. It shouldn't rumble as bad as your description but if there is a vibration it could cause some noise. 5/10000s is well within spec for runout. Some prefer the 489 case for the slightly larger pinion stem, others like the 742 for the type of sure-grip, clutch packs instead of cone clutches. They both are sturdy pieces unless you're running a four speed and serious torque (well over 500 lb ft). Many will run to the Dana 60 at the first sign of trouble with an 8 3/4 but in most cases on a street driven only car it's overkill. Personally I like the removable center section as it's easier to work on. I have done quite a few rear axle jobs under the car on other axles, the 8 3/4 is a pleasure to work on in comparison. Your carrier idea is a good one, I do something similar with a transmission jack, used to just toss it in and out by hand but it feels a lot heavier these days.

Thanks - when I ran it on jack stands they were under the axle to keep the U-joints in phase. I've also checked my u-joint phasing and they were not perfect but reasonably close. I'm relying on this mechanic as he has done dozens and dozens of Chrysler and GM rear ends for guys around here - probably some Fords too. But if it makes noise this time I'll probably just tear it down my self this time and blue print every aspect of it that I can manage.

 

[AR67GTX]

I got my rear end back and have been checking it out before putting back in. I ran out of Photobucket space and haven't learned how to generate a URL yet from Flickr so photos are in this link.

https://www.flickr.com/photos/142308046@N06/shares/y8L08f

I marked the ring gear at 90 deg intervals and checked backlash and ring gear runout.


1 position
.0105 +/- Backlash
.000 Ring gear runout

2 position
.010 Backlash
-.001 Ring gear runout

3 position
.010 Backlash
.000 Ring gear runout

4 position
.010 Backlash
+.0005+/- Ring gear runout

I was kind of reading between the lines for the .0005 readings. Not too crazy about the .01 backlash. Not sure if I should try to bring that in a little with the carrier side adjustments or leave it alone. He told me originally that he shoots for .01 in backlash.

Shop manual max runout on ring gear is .005 so at .0015 I guess that is OK.

He did show me his pinion depth setting tool he has had for decades, wooden storage box and all. He also sent the other gear set back to see if they would refund it.

Thoughts?

 

[AR67GTX]

IMG_3288 by Dan Clemans, on Flickr

IMG_3287 by Dan Clemans, on Flickr

IMG_3286 by Dan Clemans, on Flickr

Figured out how to post photos by the URL in Flickr

 

[multipleBs]

As you stated the run out is very good, well within specs but the backlash is on the high side. Most years they spec .006-.008.
I would shoot for the low side as it will increase with wear.

 

[AR67GTX]

Is taking a bit of back lash out as simple as tightening up left side carrier barrier adjustment slightly or is that likely to significantly change the overall pre-load on the bearings? Would I need to back off the right side adjuster the same as the left side is tightened up, to maintain pre-load?

 

[snakeoil24]

What is the pinion depth? it looks like to me the pinion sits to low in the ring gear. Am I seeing things or it looks off from true center on ring gear pattern. I am used to dana 60's please correct me if i am wrong.

 

[AR67GTX]

Don't know - he set it up based on manufacturer's markings on the gear set using a pinion gage tool. He was setting up a Dana when I picked my 8-3/4 up.

 

[snakeoil24]

Dana use pinion shims. 8 3/4 is crush sleeve and i just have a feeling you need to ask him what the depth on pinion should be. Your run out is near perfect.