Need advice on ring and pinion pattern.

[i6pwr]

I think I have this as good as I can get it.

GM 10 bolt 8.6"

Backlash varies in 3 points from just under .005 to 006"

Drive is slightly biased to the toe, and coast is slightly more centered from toe to heel.

Root and crown for both look good.


Drive

Coast

All input appreciated.

 

[dnewton3]

The patterns look respectable.
- the drive side looks good; there seems to be a bit of a harsh lead on the toe near the root (heavy witness mark), but the overall pattern appears decent, and is broad and centered
- the coast side is actually more telling in a rear-drive axle, and in this case it's also promising
The overall patterns on both drive and coast are consistent and broad and balanced between root and face.

As for the backlash, it should be .006" - .010", per the book by Jim Allen. So you're a frog-hair tight, but I don't know that tearing into it to try to gain .001" is worth it.

Overall I think you're good to go. Certainly worth putting the lube in and running it for 1k miles. Then it would not be a bad idea to drop the break-in fluid out, paint up the gears again and check the pattern as well as double-check the backlash. Break-in is CRITICAL for a newly built diff; don't abuse it or tow with it. Be gentle during the first 1k miles. Vary the speeds and use anywhere from light-to-moderate throttle.

 

[i6pwr]

Thank you, much appreciated.

I went back into it and messed with the pinion shims and the carrier shims. Went back and forth a few times and I may have ended up where I started, but to me it looks a tad bit better. I ran another pattern and this is where I'm at.

Backlash is now at .006-.007.

I checked in 4 locations and the tightest was a needle width under .006, but mainly .006 give or take .0005.

Drive

Coast

 

[dnewton3]

Yep - I'd say it's road worthy at this point. Good job.
As I said, take it easy and drop the fluid after the first 1k miles.
Should be GTG after that!

 

[SwampSurvivor]

After doing this on my Jeep in a friends' shop, I really need the presses, etc to do this!

 

[wpod]

After doing this on my Jeep in a friends' shop, I really need the presses, etc to do this!

Having a shop and the tools is the cats meow.

 

[SwampSurvivor]

Having a shop and the tools is the cats meow.

He had a set of pullers / presses from yukon? that's great for the typical differentials in a Jeep

https://www.summitracing.com/parts/...Ao5qJzSXGWmU0vlzo3Z5SN6RvTaxS10oaAj16EALw_wcB

 

[D60]

He had a set of pullers / presses from yukon? that's great for the typical differentials in a Jeep

https://www.summitracing.com/parts/...Ao5qJzSXGWmU0vlzo3Z5SN6RvTaxS10oaAj16EALw_wcB

There are copies like DuraSolid (let's ask a Chinese ESL marketing guy to mash two words together and come up with a name) that are a fraction of the price and well-reviewed for the most part (there are YT vids)

They're all over ebay, Amazon and even certain vendors like JBG
https://shop.broncograveyard.com/mo...lFits-All-Light-Duty-Diffs/productinfo/29659/

but you can get 'em around $200 with careful shopping

 

[i6pwr]

I had to make a small adjustment, and it seemed to work out for the better.

I swapped the setup bearings for the pressed bearings, was tightening the crush sleeve and had 15 inch pounds, gave it one more hit and ended up with almost 25.

It was too tight and I scoured the web for the correct specs, I get 15-25 as much ad I get 14-19 for these OE AAM gears.

I swapped my spare crush sleeve and ended up with 18 inch pounds.

Messed with the carrier preload and managed to get .007" backlash as well as what seems to a better pattern.

Drive

Coast

Both patterns seem to be more inline with each other.

Total rotating torque is now about 24 inch pounds so roughly 21-22 inch pounds for the carrier.

 

[mattd]

I would be happy with that final pattern.

 

[i6pwr]

I would be happy with that final pattern.

Yes, for sure.

Didn't plan for it, but once I swapped the setup bearing for the pressed bearing and opened the backlash up another .001-.002, loaded the carrier bearings, it just came together.