8.25 gear pattern check - 2nd opinion

Hey all,

It's been 20 years since I've done a gear change....it's been a slow process this time.

This (linked below) is the final assembly after fully torqueing and loctiting...which is always a bit different than test fits. Having 2nd thoughts...but also recognizing perfection isn't necessarily required.

The pinion is a bit close. Looks just on the edge of good on drive side, but likely just a tad too close on the coast side.

0.020 shims in there for photos (linked below).
0.015 brought the pinion way too far away.
0.029 was way too close (original shim stack height).

I would think anything more than 0.001-2" less is going to bring the drive side out of spec knowing my 0.015" bound

Backlash is a bit tight at about 0.0055" at closest and about 0.0075" at it's biggest gap.

I am pretty set on running it, but just looking for another opinion or two since it's been so long. I, of course, want to move on....but if there are real concerns...it'll come back apart.

Yukon 4.56 gears. Gear patterns in photos are 180* apart from each other...you can use the cross pin/pin retaining bolt as indicator of the paired Drive/Coast photos.

https://drive.google.com/drive/folders/1dqZ8QagRuiU2MXxjNA9LUkmbmMfYMMmo?usp=sharing

Drive Side 1:


Coast Side 1:


Drive Side 2:


Coast Side 2:

Heres your photos from drive.

It looks good, id run it



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I agree.
Looks good to me.

I'd use 75W-140 Synthetic in it.

I'll take 2 positive opinions and feel good about it. Thanks for taking a look!

I am going to use Autozone 75W-90 oil for break in, then swap to Valvoline 75w-90 synthetic. I am welding in a magnetic drain plug this weekend to help with that process

May I ask why you suggest 75W-140? I don't plan on towing, and it's a good 30% more expensive from my local shops.

Im partial to most fluids other than water.



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gearwhine said:

I'll take 2 positive opinions and feel good about it. Thanks for taking a look!

I am going to use Autozone 75W-90 oil for break in, then swap to Valvoline 75w-90 synthetic. I am welding in a magnetic drain plug this weekend to help with that process

May I ask why you suggest 75W-140? I don't plan on towing, and it's a good 30% more expensive from my local shops.

Click to expand...

The 75W-140 has a higher film strength when hot and under load.
The 75W-90 gives very slightly better mpg because of reduced drag.

I just like the extra protection if it's ever needed.
Either weight will do fine in normal usage.

Tune oil weight to your back lash.
Back lash at 6 run lighter 10 heavy.

Im running amzoil in my rear. To me its worth good oil since its the most forgotten but most important oil in the rig

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Thanks everyone,

Went out for a few heat cycles. Things feel and sound good.

I'll update this thread with the D30 pattern when I get there....just because.

solid