Gear Pattern.... yay or nay??

[pontiacgp]

And I agree 100%. It just came to me that the OP might be using the pinion shim to adjust backlash. No no no no no. Personally I’m glad he asked because we all want it to go right for him. And just because you have never done it doesn’t mean don’t do it. Ask away.

I like when these threads about setting up a rear end show up. Some people have the strange idea that a rear end is very complicated to set up and if you are off on the adjustments the rear end will blow. You can be off on your pattern and a bit loose on the backlash and that won't blow it up but the rear end will be noisy. Once you do one you'll see it's not that bad of a job to accomplish. The worst part for me is crushing the sleeve

 

[Bonnewagon]

they typically do not have a check distance engraved on them to go by.

What is that exactly? The only marks I have ever seen on a pinion besides the tooth count was the "+" or "-" that you must add or subtract to your pinion depth after determining it by using the depth tool. That number is what the manufacturer decided was necessary to get the best relationship between the ring and pinion FOR THAT PARTICULAR SET. That is important because when the ring and pinion are lapped together during manufacturing they may need that extra bit to get the absolute best engagement. Even if the gears are swapped to another carrier that relationship must be maintained by adding or subtracting the number on the pinion.

 

[500/600]

Check distance varies by manufacturer. On a typical GM 8.5 it’s the distance from the rear facing flat surface on the pinion to the center of the carrier bearing saddles. I’ve seen GM pinions with a step on this surface so who is sure which they measured from? Aftermarket pinions have this measurement engraved on them. Factory gears did not that I’ve ever seen. Whatever shim came on a pinion from the factory is the way to go. If you know what your looking for you may go thicker or thinner. Most folks no. Ring and pinions are forgiving. I have seen perfectly set up aftermarket sets that were noisy. I’ve never seen a stock set be noisy unless someone accidentally left the shim out or had no backlash. It is not black magic, but if you screw around and get it way wrong it could be catastrophic at speed. It would however have very likely given very physical or audible indication of issues prior to detonating.

Use the stock pinion shim.

 

[1983calais]

I like when these threads about setting up a rear end show up. Some people have the strange idea that a rear end is very complicated to set up and if you are off on the adjustments the rear end will blow. You can be off on your pattern and a bit loose on the backlash and that won't blow it up but the rear end will be noisy. Once you do one you'll see it's not that bad of a job to accomplish. The worst part for me is crushing the sleeve

Try a crush sleeve eliminator. Much nicer! No need to worry about over crushing. Just add or take away shims.

 

[Bonnewagon]

Factory gears did not that I’ve ever seen.

That explains it. All I have ever used are GM gears. Thanks for that.

 

[Bullett801]

Great info guys! Really, thank you all so much. 500/600, i am not adjusting backlash with the pinion shim sir. Bonnewagon has given me a ton of info prior to starting this and was very specific on how to adjust what and in what order, so I am following that to a "T". And you are correct in saying the OE 3:73 gears that I haved do not have thge depth marked on them, or a + or - either. I measured the pinion depth with a tool from RATECH. It is primitive, but I measured it multiple, multiple times before I removed the original pinion gear. And all the measurments were within .002 of each other. I put the pinion shim back in that came with the pinion gear, pinion bearing preload is at .020 in lbs, have the carrier set at .000 and backlash set at .010. Bearing caps torqued to 65 ft. lbs, just waiting on the compound now. As soon as I get a good, visible pattern I will put up a pic or 2 and get ypur feedback. I really appreciate all you guys's advice and wisdom.

 

[Bullett801]

Try a crush sleeve eliminator. Much nicer! No need to worry about over crushing. Just add or take away shims.

I got one from RATECH, and on the final assembly that was what I was going to install, but not for setting up I was told.....

 

[pontiacgp]

Great info guys! Really, thank you all so much. 500/600, i am not adjusting backlash with the pinion shim sir. Bonnewagon has given me a ton of info prior to starting this and was very specific on how to adjust what and in what order, so I am following that to a "T". And you are correct in saying the OE 3:73 gears that I haved do not have thge depth marked on them, or a + or - either. I measured the pinion depth with a tool from RATECH. It is primitive, but I measured it multiple, multiple times before I removed the original pinion gear. And all the measurments were within .002 of each other. I put the pinion shim back in that came with the pinion gear, pinion bearing preload is at .020 in lbs, have the carrier set at .000 and backlash set at .010. Bearing caps torqued to 65 ft. lbs, just waiting on the compound now. As soon as I get a good, visible pattern I will put up a pic or 2 and get ypur feedback. I really appreciate all you guys's advice and wisdom.

"have the carrier set at .000".? .... 🤔

 

[1983calais]

I got one from RATECH, and on the final assembly that was what I was going to install, but not for setting up I was told.....

I like to get it real close with the mock up bearings. Then after you get all your tolerances and backlash set, press your pinion bearing on and check your preload. Add a shim or take away a shim. May only need .003. But like I said, much nicer than a crush sleeve. You’re going down the right path. Great job.

 

[Bonnewagon]

I measured the pinion depth with a tool from RATECH.

There ya go! The right tool for the job.