I have a 9 bolt rear end, I have installed a 3.70 gear US gear from strange.
I have sent photos to strange and US gear axle tech line with no response.
I have recieved a reponse from Randys ring and pinion and they said the pattern looks good.
My question is,Why cant I seam to get a respectable pattern on the coast side,and if I cannot,will this thing be loud?
It has all new bearings, Pinion shim is at .022 and backlash at .011.
Has anyone seen this goofy pattern on the coast side?
I have spent countless hours trying to improve upon what I have,only to
make it worse.
I have spent countless hours on several pdf gear install instructions and
service manuals.
I have spent countless hours looking on the internet for any pattern posted
on the internet,seen none like this coast side.
I am out of ideas.
Thanks

 

From what I can see, the pinion is too deep. Try taking .005-.007" of shim out and try again.

 

These were at .024 pinion shim,The pattern improves on the coast side
but pattern on drive not so good. I had tried no shim .017 shim,.020 OE shim,and .033 shim.
The best patterns on the drive side have been with the .022 shim.
The other patterns werent worth taking photos of.

 

Welcome to the "find the perfect pattern" club. What does U.S.Gear recommend for backlash, .011 seems a little too much, usually around .008 -.010 is what i have been told to use.

 

First, don't use so much marking compound. You only need to mark 3 teeth in 2 or 3 locations. That gives you some clean teeth for the pinion to clean it's self on. Also, use an axle to turn everything. That will give you longer smoother stroked with less chatter marks in the pattern. Be sure that you set the pinion bearing prelaod the same each time you check the pattern. The bearing preload should be close to 20 inch pounds.

It looks like the .024 shim is better. Pay close attention to the root to face pattern and not heel to toe. Root to face is much more important than heel to toe. Pinion depth controlls root to face and backlash can be used to make fine adjustments to heel and toe.

I recommend cleaning the teeth and checking the pattern again like I posted above. See if you get a more clear pattern. I think .024 is going to be your best pinion shim from what I see now. Backlash should be set within the manufacturer's recommendation, but in your case I think I wolud go with the widest backlash allowed.

 

Thanks.
I will keep you posted. You have some good points.
I was able to get some more shims from GM.
I will repost soon.

 

Thanks, The Us gear spec is .008 to .012.

 

This setting is at .027 pinion and .010 backlash.
Comments please. Thanks

 

Looks pretty good, but maybe a little deep on the drive side. Did you try the .024?

 

This is .025 with .011 backlash.

 

Not bad. This might be the best that you can get with the gear that you have. I think I would try it like this.

Just wondering, did you try changing the backlash to see if it got any better?

 

Over 7 years later ! I am going to finish this rear end with the brakes. Finally just dropped off the calipers and brackets for the powder coating. Wow how time flies. I need to get back on my car as has been stored for 16 years. I want to finish this rear end. Life is short and if something happens to me I want the car to be driven again for someone. Anyways,I have been looking to put on bolt on relocation brackets for the rear end when I put it in the rear end. What brand would you recommend. Thanks