Vesa

Hi Gary or any other Guru!

I have now set the backlash to 0.007-0.009. Actually I think the average is now 0.008.

After that I looked the pattern by painting some gears white. The drive side was very deep and to the toe. Cost side was very deep and to the heel. So I changed thinner pinion shim (0.006"thinner) and the pattern moved right when I think only about deep / high and it is right both the drive and coast side. But drive side is still to the toe and coast to the heel. The drive side: on toe end 1/5" is without contact and on heel end 2/5" is wirhout contact - so this look close to what the quidebooks say about "Performance pattern". The shape of the drive side contact is quite nice oval and on coast side like a triangle and the sharp edge of the triangle is facing towards the toe. Should I leave it here now? I can not move either side (drive or coast) deeper or higher since they are now perfect...
What does "performance pattern" actually mean? Why is it used in performance applications? What advantage and possible disadvantages it offers compared to the " normal pattern"?

Help me guys

GTR1999

moving to a thinner shim with good backlash will move the drive side to the top and toward the heel. The coast moves to the top of the tooth and a little to the toe.
The perfromnace pattern is setup with the pattern to the toe so that under load it will flatten and move to the heel. Did you load the gears by applying tension while rotating them forward and reverse? also the typs of marking compound makes a difference. I like the yellow paste as I think it shows much better.
Here is a picture of the pattern I just did and it was with a .030" shim. The original was 029 so .030 should have been pretty close,but with a new bearing set and new gears you can't count on that.

Drive





Coast



As you can see they aren't where I'd like them. I ended up, after several changes going to a .022" shim.

Here's the final patterns.

Drive




Coast




It will be hard to get a book perfect pattern. A lot depends on the gear set used. Tom's are cut differently then most and usually set to the toe. If you have a pattern like the first one you need to shim again until you get equal centering on the tooth. Try to avoid those sharp angles too,should be lie a cigar- rounded and centered.

Good luck

Vesa

Thanks, I think I need to change still 0.002" to thinner shim. I tried to "brake" with my other hand (on carrier flange) while other rotating the side yoke...but maybe not braking hard...

Still coming back to the question on advantages of the Performance pattern - could it be used because it tends to be a bit deeper and to the toe under normal load and around perfect pattern under heavy load meaning (compared to perfect pattern under normal load and too high and too much to the heel under heavy load) that the tooth do not break so easy when the pattern does NOT go HIGH around heavy loads (tooth are thinner and not so strong when going higher with the pattern)?

Vesa

0.002 thinner shim helped the coast side and the drive side is now almost perfect slightly to toe - im satisfied now...thanks!!

GTR1999

Good to hear, can you post some pictures of what you have? Again trying to get a book perfect pattern may not be attainable. The important thing is to get the pinion in the correct position. There may be several accepatable patterns again depending on the gears used.

Lionsden

I came across this installation guide a while back.

http://www.drivetrain.com/ringpinioninstal.html

Vesa

I do not have my digicamera here awailable, but I try to explain:
Now the drive side looks like in your final pictures your coast side! Maybe just very slightly more to the toe. Anyway it is a big oval nicely starting right after toe end and at the heel end ending a bit earlier that at the toe end. And isn´t it more important to get the drive side set close to "perfect" than the costs side...
Coast side (especially the heel area) looks like your coast side in the first picture, but the contact reaching more towards the top and toe in the toe area.

Vesa

yes, thanks its a good one

Vesa

My gear set is by the way GM original 4.11. They look fine so I decided to reuse them from the old carrier. Now everything else is new but the case and the gear set.

Retro78

That is a great document for gear setup. Thanks