Differential question

[pontiacgp]

:?

 

[Bonnewagon]

I take my hat off to anyone who digs into rear gears without fear. Most mechanics will give you a blank stare when you ask about setting up gears,so carry on,it's becoming another lost art. There's no real "measurement" of the carrier preload. Once you get it to "zero" play,meaning you can't get a .001" feeler gauge in there,then you add .004" to both sides. That way you add .008" additional shim thickness without disturbing the position of the carrier.The factory used a special tool to install the cast iron shims you find in a stock setup without breaking them. Service in the field requires steel shims so they don't break.Adding the .008" forces the bearings into the races and assures they don't move under load. A circle track car can get away with special settings,but a road car that must last thousands of miles had better be right on. The original question was can you just change the carrier to a posi. Yes,you can, as long as it is reset to factory specifications.Should a guy not familiar with ring and pinion service try it? With the GM factory service manual, dial indicator, and a shim set, yes. Otherwise,no.

 

[pontiacgp]

What do mean by right on?....as far as the pinion depth goes look at any chart that comes with a bearing kit and you'll see how much tolerance you have with that depth. As for the carrier as long as you have the backlash 6 to 10 thou and it fits into place with a light tap of a hammer and does not fall out inverting the differential you have the preload on the carrier bearings is fine. A circle track car gets more sideload and heat buildup than you'll ever get on a street car but you don't set up a circle track car any differently than a street car. If a rear end isn't set up properly either in a circle track car or a street car it'll grenade long before a 1000 miles whether on the street or track. You might look up references to rebuilding a rear end but have you ever actually done one in real life? People like yourself are the reason I don't particularly like posting in this form. I am speaking from actually building rear ends and I was taught by a guy who's be doing it for decades. I have access to mechanics in different divisions of nascar and other series and I know many mechanics. I don't understand how you think to try to argue against that depth of knowledge.

I didn't bother posting for a while and I think I'll I go back that way.....

 

[Bonnewagon]

Don't get mad. By "right on" I mean set up to factory specs useing a factory manual and a factory ring and pinion installation tool as found in a dealership. I've set up dozens of rears and all are still quiet and smooth. Full time mechanics come to me to set up their rear gears. I'm not trying to argue with you, but just because you have someone that taught you how to get by without the proper tools and specifications, you shouldn't be advising guys with no knowledge at all to be messing with something as critical as rear end gears. Ever read a factory manual? If so you wouldn't be whacking in shims with a hammer and thinking "tight is good enough". Peace.

 

[pontiacgp]

Don't get mad. By "right on" I mean set up to factory specs useing a factory manual and a factory ring and pinion installation tool as found in a dealership. I've set up dozens of rears and all are still quiet and smooth. Full time mechanics come to me to set up their rear gears. I'm not trying to argue with you, but just because you have someone that taught you how to get by without the proper tools and specifications, you shouldn't be advising guys with no knowledge at all to be messing with something as critical as rear end gears. Ever read a factory manual? If so you wouldn't be whacking in shims with a hammer and thinking "tight is good enough". Peace.

so tapping a shim in place turns into whacking in shims with a hammer?..I won't bother correcting you on the rest of the inaccurate accusations ..perhaps you have read a factory manual and it looks like that's as far as you got.

and I don't get mad, I just don't like wasting my time with people like yourself

 

[Chris Van]

Let me save both of ya'll from whatever it is that you are arguing about.....
I just happen to have one of those 8.5's for sale.
4.10 gear, moser axles, c-clip eliminators and spool. Though you may want to swap that part for a posi unit if you are gonna see much street use......
$1200 bucks..... COMPLETE drum to drum.... even the brake lines.... Just bolt it in...