Check my gear pattern :)

[A1971Blazer]

Originally Posted by superhondaz50

Got backlash at .009, spec is .006-.10 so on the higher end but in range, I'll measure shims and see if I can get it to .007 or .008

.009 will work just fine.....as good as your pattern is....it should run quietly...not every one agrees but the guy who taught me....always put the vehicle on jack stands and ran it for about 30 minutes to warm it up...then let it cool slowly...and you're good to go....did you replace the carrier bearings?

[superhondaz50]

Originally Posted by A1971Blazer

.009 will work just fine.....as good as your pattern is....it should run quietly...not every one agrees but the guy who taught me....always put the vehicle on jack stands and ran it for about 30 minutes to warm it up...then let it cool slowly...and you're good to go....did you replace the carrier bearings?

Ya, full bearing replacement.

[6T7 C10]

I am of the opinion let it run. Looks really good and the pinion shim thickness is closer to original and what I ran and your backlash at .009 is within tolerance and what I ended up with as well. Mine only has a few miles on it but works and sounds perfect. Good luck to you as I think you are very good.

[superhondaz50]

Originally Posted by 6T7 C10

I am of the opinion let it run. Looks really good and the pinion shim thickness is closer to original and what I ran and your backlash at .009 is within tolerance and what I ended up with as well. Mine only has a few miles on it but works and sounds perfect. Good luck to you as I think you are very good.

Cool, I'll rock it. I'll pull the set-up bearings tomorrow and install the finals. I'd like a closer backlash but the best I could do is move .005 from one side to another which is too little backspace.

Mines gonna get alot of miles on it running jetskis from California to Arizona and back.

[randy500]

Post 9 is your best pattern, although your first pattern was good too for a performance application and most gear sets are lapped for a toe pattern. There is a corvette guy that does a lot of rear ends, I will find. A pic of his patterns and Post back.
The current pattern will put way too much load on the heal of the teeth and if you have horsepower will break a tooth.

The pattern on the drive side should be slightly towards the toe since under load the pattern will shift to the center. Don’t worry about the coast pattern as far as placement unless way off.
If you can you should be putting a load on the ring gear and turning the pinion with a socket. You can rig up a couple bolts and a hard wood block to load the ring gear.

[randy500]

Here is a pattern chart which should be helpful, note competition pattern is towards toe of gears.

[superhondaz50]

Originally Posted by randy500

Post 9 is your best pattern, although your first pattern was good too for a performance application and most gear sets are lapped for a toe pattern. There is a corvette guy that does a lot of rear ends, I will find. A pic of his patterns and Post back.
The current pattern will put way too much load on the heal of the teeth and if you have horsepower will break a tooth.

The pattern on the drive side should be slightly towards the toe since under load the pattern will shift to the center. Don’t worry about the coast pattern as far as placement unless way off.
If you can you should be putting a load on the ring gear and turning the pinion with a socket. You can rig up a couple bolts and a hard wood block to load the ring gear.

Ok thanks, horsepower is only 250, but it does have 35" tires. I was putting load on the pinion with a breaker bar and a wrench on the carrier... I really couldn't get the drive pattern to shift towards the toe much at all. Either way, gotta get this right, the local shop wants $2k to set this up.

[superhondaz50]

I'm thinking if I can pull the backlash in to around .008 some how I'd get a better pattern. The coast and drive pattern are in the same spot, seems to be centered top and bottom, backlash should pull it center a bit. BTW this is a hobbed gear.

[randy500]

Originally Posted by superhondaz50

Ok thanks, horsepower is only 250, but it does have 35" tires. I was putting load on the pinion with a breaker bar and a wrench on the carrier... I really couldn't get the drive pattern to shift towards the toe much at all. Either way, gotta get this right, the local shop wants $2k to set this up.

Look at your first pattern it was towards the toe. Here is a pic of the corvette guys pattern, he has a motor to turn the diff with a load so he gets a real clean pattern.
I usually turn my pinion with a slow speed 1/2” drill while loading the ring gear with a block of wood....cordless dewalt or other good drills on low speed will work too.

[superhondaz50]

Ok, ya, looks like I'm way off compared to that pic. I think I'm just gonna have to give in and take it to a shop, I can't have this thing let go when I'm in the middle of the desert when it's 120* outside haha, I can say I tried.

[superhondaz50]

.032 with .007 backlash

[superhondaz50]

.035 with .008 backlash

[superhondaz50]

Post #9 shows .039 with .007 backlash

I can go to .037 too and take a pic for you guys if needed.

[superhondaz50]

For future reference and searches, I showed a rear end builder my gear patterns (.039, .037, .035, .0335/.034, .032) and he said the .0335/.034 shim and .008 backlash were on the money for my Richmond set, so I'll be rocking it as shown below. It looks good to me also but what the heck do I know.

Ok, here it is .008 backlash with with a shim on .0335/.034.

[superhondaz50]

Well, my wife helped me button up the rear this past weekend. Set the preload around 19-20-inlb, new bearings, Moser yoke, and a Spartan locker. Hopefully it'll work, I'll know in a month or so once I finish assembling the truck. If not the local guy is gonna charge me $1200 to fix it -_- I'll post up here again to let y'all know.

[Boog]

Better hope you did it right then.
Man, I need to get in the differential business.

[superhondaz50]

Originally Posted by Boog

Better hope you did it right then.
Man, I need to get in the differential business.

Yup, if it goes out I hope it does in the most fantastic Michael Bay style explosion with flames and what not, so I at least get a show for the time I put into it hahaha

[randy500]

I'm sure it will be fine...none of the patterns you had were far off from ideal.

[bbrriiaann1973]

That backlash looks good to me. I have a 12 bolt 3.73 ring and pinion with a lock rite posi.