I just got an eaton posi a 3 series carrier and got some used 3.73 gears for a guy at work who only had them in his car for a summer. Now i went to put the ring gear on the posi just because i was cleaning everything up and it wouldnt go on. I gave it the torch for like 3 or 4 minuates and it went right on??? is this normal? and if it isnt what are the consequeces of this? and i am also debating weather to have my ring, pinion and posi put in by a pro or get bold and try it myself. Any thoughts on anything from some of you drivetrain masters???

 

very dangerous an yes is normal but i normally set the oven for 350 heats it up evenly and reduces chance of destortion this will work with many parts in this job you are taking on

 

Using a SMALL amount of heat is fine. Yes it's normal; they're normally just a very very slight interference fit, I'd guess no more than .001" or so. Just enough that there's absolutely no chance whatsoever of the ring gear wandering around on there.

If you've got the right tools, and it's NOT a Richmond gear, then you can probably do it yourself. Use a .035" shim under the pinion head bearing, and shim the carrier for about .008" - .012" of backlash. Make yourself a tool to hold the pinion still while tightening the nut, out of a piece of about ¼" x 1½" bar stock about 3-4' long, by drilling 2 holes along the edge near one end and bolting it to one of the U-joint "ears" of the yoke; tighten the pinion nut until all the play goes away, then continue to tighten SLOWLY and in SMALL INCREMENTS until it takes about 20-25 in-lbs (just slightly under 2 ft-lbs more or less) to turn the pinion in the housing.

If it IS a Richmond gear, and you plan on driving it on the street EVER, AT ALL, I'd suggest selling it and getting something else. If it's a strictly strip-only car, trailered to the track, then use it; but the .035" shim probably won't work. You'll need a pinion depth gauge.

 

what ever dude .035 unless its a richmond dude this is part of the job when ever you change gears do not take chances and your gears will live

 

i also heat the bearing for easy install take your stock pinion bearing to local machine shop have couple of thou taken off the bearing race so it just slides over pinion shaft for easy pinion depth setup

 

.035" shim under the pinion is a good starting point for most GM rears. However, let me share another method that my neighbor showed me a couple years ago. Keep in mind this neighbor had his own shop for 30 years and raced Pro Stock back in the 60s. He's a better wrench than me and he really proved it on this one......

DON'T SET UP THE GEARS! Take all the stock stuff out, reuse the original pinion shim on the new pinion, keep the factory left and right carrier shims in their original places (mark them so you know which side they cam out of- left or right and make sure they get back in that side). Reassemble with new parts.

Nuts, right?

That's what I thought until we actually did it in the original 10-bolt under my wife's 92 Camaro. And I'm talking about the worst possible nightmare combination you can imagine..... going from stock 2.73s on an open diff to 4.10s on an Eaton Posi. And I'm talking about RICHMONG GEAR 4.10s, thank you- the ones everybody has problems with. The only check we did was a quick gear mesh contact pattern check with marking gease (which looked perfect, by the way).

I expected a whining, grinding mess out on the road. But to my absolute shock the gears were almost DEAD silent. I'm talking as quiet or quieter than stock. I've NEVER heard a set of steep Richmonds run this quiet- EVER! I put thousands of miles on the car- still quiet. It's hands-down the best 4.10 + posi upgrade I've ever seen or even heard about. I still can't beleive how well it worked. The old man definitely gets a gold star for this one!

One thing I will note about the Richmond install kit- the shims are pieces of crap, especially the pinion shims. They can't seat down cleanly over the radius where the pinion input shaft meets the back of the pinion gear itself (the factory pinion shim wisely has provisions to prevent this exact problem). I wouldn't be surprised if that issue alone has caused some of the reported problems with Richmond Gear installs.

No magic. No "secret recipe." No facts or information left out of this story. It is exactly as I wrote it, above. Nothing more or less.

 

this is how i do my installs but it seems to never fail i have to add a thou or two here an there because i allways check the backlash with a dial idicator and pinion depth by contact pattern

 

but i must say ive been told this before an not heard of to many problems but being i work for auburn gear i know what the tollerances are on the casting and there are know two alike and you are talking a few thou either way

 

Some diesel engines requires gears to be heated up to be installed. As mentioned in the first reply, I was also going to say to use an oven to 350 degrees. That's the typical temperature for heating up parts like that. At work when I use a torch, I use a heat gun to check the temperature of the part. You can also get special wax pencils that are designed to melt at a specific temperature. Hold a 350* pencil on the part. It doesn't melt, it's not hot enough. Downside is that you don't know if it's too hot that"s why I like the heat gun.

Heating up a part to 350* only makes it expand a few thousands of an inch. You're not heating it up cherry red where you can lose the temper of the metal.

You can heat up a ring gear for a flywheel with a simple propane torch. That's all the heat it needs to expand.

 

Had to go back and read all the replies.

Doing the pinion shim is always a pain. It's hard to remove the bearing once it's been pressed on without destroying it. A driveline shop that does this regularly has a trick. They have a new pinion bearing that has the center machined out a few thou. This allows the bearing to easily slide onto the pinion without needing to be pressed on or off. They set the diff up with this bearing. Once the proper shim is found, the new bearing is then pressed on over the shim.

Of course they should also have pinion depth gauges and should know what shim to use the first time from the numbers written on the end of the pinion.

 

Moving to Transmission/Drivetrain from Tech.

 

I have one llike that; I just took a brake hone to its bore. Pretty easy DIY job.

Incidentally, I have yet to take apart a factory 7.5" or 8.5" 10-bolt, and find ANYTHING BUT a .035" shim in it. Kind of makes me wonder why the factory even bothers with the shim, and doesn't just make the parts where they don't need it, since they seem to be able to get that particular spot facing for the bearing bore in the housing pretty consistent. So yeah, check what's there and put back in what you found; but I'd say that 95% of the time or more, it'll be .035". And, factory carrier shims are cast-iron, and are bad about breaking when you try to re-use them; so I don't plan to do that if I can help it, I try to always get a kit and use the nice steel ones that come in it. Often, stacked up to exactly match the original factory ones; just made of better material.

 

enjoy your sofa guys like this get wrote up and fired where i work because of people like this bad parts get out the door 95% of the time your doin what you shouldnt an that leads to sloppy work stay on the sofa we want it right