489 gear pattern setup results - #2 Final Round ( I hope)

[AR67GTX]

489 with pinion spacer. After many trial setups I installed the new pinion bearing cones and races, adjusted the shim thickness for differences in bearing height from set up bearings and new bearings and put it together in semi final form. I had to make a lot more downward adjustment in pinion preload shim thicknesses than I anticipated, finally getting up to 19 in-lbs on my cheap 1/4” beam scale torque wrench. That’s a little on the low side for new bearings but it feels pretty stiff.

I think my pinion depth transferred over to the new bearings with the small adjustment I made. Here is the pattern with .006” backlash:

And here is the same with .007 backlash:

It looks like the drive side may be a bit close to the crown but it’s still getting a full pattern. I think the coast side, which seems to be more influenced by pinion deth than anything else, looks good IMO - 100% better than where I started. I just can’t seem to get a better imprint than this with the Richmond yellow paste. I suspect it’s because the teeth polished up some in the 15 miles or so I put on it.

Look good enough to install the seal and torque up for a try??

 

[PlymCrazy]

Might I say I'm very impressed by your persistence in getting this just right. I've seen you post about this previously at least once or twice as you progress. You are a perfect example IMO that there isn't anything we can't tackle on these Mopars when we put our mind to it. And the technical support folks here have to offer, we're all bound to be successful with our endeavors with our own. Even if it takes a few tries.

 

[steve340]

The pattern is a bit unusual as it goes from the top to the bottom of the tooth. You don't want the pinion "buried" in the crown wheel.
The gears may not be manufactured correctly but just my opinion.
I guess it may be as close as you are going to get so my 2 cents - button it up and hope it is good.
No way of really knowing until you drive the car.

I believe from earlier posts those gears were howlers so that hopefully has improved.
Can you update when you drive it please.

 

[AR67GTX]

These are 5 cut gears and from what I could find out, they are distinguished from 2 cut gears in typically having a longer contact patter from toe to heel that will flare or widen towards the heel. The 2 cut gears were said to have a shorter contact pattern toe to heel. I’m not knowledgable enough to know if that is just BS or not. But that’s what I read on the internet.

StackPath

 

[Cranky]

These are 5 cut gears and from what I could find out, they are distinguished from 2 cut gears in typically having a longer contact patter from toe to heel that will flare or widen towards the heel. The 2 cut gears were said to have a shorter contact pattern toe to heel. I’m not knowledgable enough to know if that is just BS or not. But that’s what I read on the internet.

StackPath

Been a few years since setting up gears that came from Yukon but have done 4 new sets in the past and don't recall any paper work about 2 and 5 cut gears....

 

[AR67GTX]

Cranky - that’s what the “StackPat” attachment above covers. Don’t know why it attached with that title.

Steve - actually there could be something about your observation. I searched again and finally found US Gear install instructions on a Strange Driveline site. None came with the gear set. Apparently Strange, Moser and US Gear have some sort of relation with each other. Anyway, while they suggest .006 to .008 backlash for a strip setup, they recommend loosening that up to .008 to .012 for a street set up. So I will need to open up the backlash some which will pull the ring gear out from the pinion a little. Have to what it looks like then.


Edit: aghhh - should have said .006 to .008 for strip set up . .

 

[steve340]

I have found the set up principals are the same no matter what brand of gear or make of car. Generally.
By this I mean the contact pattern regarding heel/toe and face/flank you are always told the same pattern is desirable.
Good luck and for being willing to give it a go.

I did a diff for a friend of mine that we did a marking before pulling it apart and it was terrible - but the diff looked like it had run that way for a while. It was second hand.
Tried all sorts of tricks and adjustments but nothing worked out. We came to the conclusion the diff gears were too worn so we just slapped it back together. The only thing we did was machine a solid pinion pre-load spacer.
When he got the car going the diff is absolutely silent under all conditions. I was very surprised.
I hope you are as lucky.

 

[AR67GTX]

Wow, I hope so too. You guys should have gone right out and bought a Mega Millions lottery ticket after that.

 

[66Satellite47]

With 8 3/4 set up's I had difficulty getting the "perfect pattern". So since mine was a drag car I concentrated on the drive side pattern. I could get that pretty good. I didn't care about noise. After switching to a Dana, the setup got much easier. I did use a slip fit pinion bearing so getting the shims right was pretty easy. I was able to get a nearly perfect pattern with no problem. Same for all the Dana's I did after that. No idea why such a difference between the 8 3/4 & Dana.

 

[AR67GTX]

In my case the drive side pattern and backlash seemed to be the only thing the drive line shops around here looked at or paid attention to. The Richmond gears the first shop set up had a funky pattern on the coast side but the drive side looked OK and backlash was OK. These US Gears the second shop set up had the same funky coast pattern but the drive side looked OK and backlash was OK. I just made one short test drive in it and knew I couldn’t live with it.

As I played around with the pinion depth I found that that was what seemed to bring the coast side pattern in and out of proper pattern and it centered only in a fairly narrow range of pinion depth. Going either way seemed to send it into the root or over the crown. It appears both shops were setting up the pinion too deep into the ring gear and not getting the coast pattern right.

The pinion depth as I deepened it into the ring gear, sent the drive side pattern towards the toe and into the root. As I went to a shallower pinion depth the drive pattern went over the crown but stayed centered toe to heel. But the drive side pattern seemed to hold up better over a wider range of pinion depth overall than the coast side.

The one thing I didn’t experiment with enough to fully understand the effects, was the backlash. Since it’s still on my bench and since I’ve been thinking maybe I need to thin the preload shim a hair more to get the pinion torque above 20 in-lbs, I may go back and run backlash at around .004 and then .0012 to get a better understanding of how it affects pattern overall.

But, I’m hoping that the coast pattern will bring the light throttle and coast whine noise down to an acceptable level. We’ll see. If not at least I will have learned a lot.

 

[Cranky]

I have a setup tool that's been my savior for years but it's another story if the gears ain't marked from the manufacturer. If the gears are not marked, then you have to go by what's called the mounting distance. You have to measure the thickness of the pinion gear head and go from there. From the very start, I didn't trust the setup tool since the pattern didn't make sense to me back then so I would stick in the chunk (8 3/4) and go for a test drive and after doing that with 4 different chunks and the gears being quiet, the trust of the tool was there and didn't worry about what the pattern looked like. I started out just doing gears for myself but it snowballed.....

 

[AR67GTX]

The gears were marked but I didn’t have an understanding of exactly how to apply them - I figured you needed a set up tool. My theory was that the shop got it somewhere close and bracket that with some trial set ups. I know the guy who set up the Richmond’s had a set up gage. Not sure about the last shop. Are some of the tools/gages generic where they will work for different rear ends?

 

[66Satellite47]

BTW both my 8 3/4 gear sets were Richmond. I did try to vary the backlash to make the pattern better. I finally did just focus on the drive side which I could get to look real good. Other factors caused me to switch to the Dana. I was surprised that the Dana pattern came in so well with few iterations. The first Dana gears were Direct Connection, second I think were Richmond.

 

[khryslerkid]

The one thing I didn’t experiment with enough to fully understand the effects, was the backlash.

At the end...

 

[Cranky]

The gears were marked but I didn’t have an understanding of exactly how to apply them - I figured you needed a set up tool. My theory was that the shop got it somewhere close and bracket that with some trial set ups. I know the guy who set up the Richmond’s had a set up gage. Not sure about the last shop. Are some of the tools/gages generic where they will work for different rear ends?

My depth checking kit will do several different rears but won't do a Dana 70 or the larger ones. When I replaced the gears in my diesel (Dana 70) I had to used my depth mic and round off the tip of the corresponding measuring rod to measure the bearing fit depth to see if the halves of the housing and bearing cap was the same. They weren't but wasn't far off. Really needed a wide base depth mic with a dial indicator mounted on it. Not quite as accurate using a regular depth mic with the modified measuring rod but at least it got me real close and then relied on the pattern. The depth mic is accurate measuring from the flats where the cap bolts to though. When I started doing gear setup, we didn't have the internet to look at pics and had to look at what was in print which didn't look like anything that I saw on the gears lol. IIRC, when we finally was able to get the internet, my youngest was already about 7 or 8 so that would put it around 1995-96 and I had already done several setups. Pretty much all were 8 3/4 with one 9" and one Dana 60.

 

[AR67GTX]

Well, bit of setback. I thought before I got too much further along I better torque up the pinion nut pretty high as I didn't know how high my somewhat anemic electric impact was going and make sure my preload was really firmly set. After putting about 100 ft-lbs on it, it got real stiff so apparently one or both of my bearing cones didn't get seated fully when driven in or torqued at a low setting. So I'm backing at setting preload again. Torqued up my last try to about 150 ft-lbs but preload is still a bit light so need to take another thousand or two out and try again. Hoping that doesn't change my pattern but if the rear cone wasn't fully seated it might. At least I have lots of pictures and all sorts of piinion depth so that will help me zero in again if necessary. A lesson learned.

 

[padam]

I wonder how many flat rate mechanics slapped these together with an impact and never had an issue.

 

[khryslerkid]

That's a "rolling" torque just like doing the carrier bearings. Torque 20 lbs or so then rotate the bearings. 20 or so lbs more and rotate again until you reach your goal torque. The roller bearings need to seat themselves in the cone while rotating. Impact gun bad. You can nick a cone easily.

 

[Cranky]

Well, bit of setback. I thought before I got too much further along I better torque up the pinion nut pretty high as I didn't know how high my somewhat anemic electric impact was going and make sure my preload was really firmly set. After putting about 100 ft-lbs on it, it got real stiff so apparently one or both of my bearing cones didn't get seated fully when driven in or torqued at a low setting. So I'm backing at setting preload again. Torqued up my last try to about 150 ft-lbs but preload is still a bit light so need to take another thousand or two out and try again. Hoping that doesn't change my pattern but if the rear cone wasn't fully seated it might. At least I have lots of pictures and all sorts of piinion depth so that will help me zero in again if necessary. A lesson learned.

Another thing to look at is if the radius behind the bearing isn't bigger than the inside diameter of the shims. That can and will change things especially when you tighten things up.....just went through that same thing with a Dana 60 both on the carrier and on the pinion. I'm just glad I had a radius gage set to check once I thought that might be a problem and found that ALL radii were larger than stock stuff. Larger than stock ID's shims are available but they are a pita too.

 

[AR67GTX]

I used a 3/8“ somewhat anemic battery impact to run down the pinion nut to pull the front bearing on and snug up the nut, and only with the carrier out while I centered the yoke. I dont think it has enough ummphh to do much to anything. Beyond that I went to a torque wrench. Finally got the pinion preload to 28 in-lbs which was a little higher than I was shooting for but with .0005” less shim it was still a little low so I quit there. It stayed stable and smooth to 170 ft lbs on the nut. Fortunately the pattern looked the same - maybe a bit cleaner as the extra drag helped produce a cleaner imprint in the gear paste.

Cranky my shims seemed to fit fine but I guess they are all rough stamped out anymore. I couldn’t a stable measurement on any of them with my caliper as they seemed to have a sheared, distorted edge from the stamping. I had to file the ID & OD edges on all of them and then sand their faces with emory cloth on a flat surface with an aluminum block. After that they would measure uniformly around their radius with a caliper and I could figure out what I was doing.