Hey guys, what are the correct tools I need to swap the rear out? I've already got the gears but need to change the posi out, so I might as well replace the crush sleeve and all that when I'm in there. I already have a dial indicator; do I just need a dial torque wrench? (I just have the click-style torque wrench.)

Thanks!

 

(laughs) Wow, nobody knows? Or did my message just get pushed down too far?

 

Not sure if I read your post correctly but it sounds like you are installing a new set of gears in the rear?
If so, I always use a pinion depth gauge, comes in a kit and range from $100 to $300. It allows you to shim the pinion to proper depth using gauge according to gear manufacturer specs. You will need a new crush sleeve to get proper preload on pinion bearings, and an inch pound wrench is used to determin that by rotating pinion with inch pound wrench while pinion is in housing by itself, usually look for 20-30 inch pounds depending on type of rear etc.... You will also need a shim kit, usually a good quality install kit will come with seals, bearings, crush sleeve, and shims along with gear marking compound also.
Some people use gear marking compound to set up gears and go by pattern only and that works fine if you know what to look for and how to correct it. This method will take several tries usually. I like the pinion depth gauge method, I usually get a good pattern on the first try if using pinion depth gauge and set it to gear manufactures specs. Then set back lash with your side shims (GM rear) and after I am done I also use the gear marking compound to check pattern for the heck of it. Usually comes out perfect if I set the gears up with gauges first. Hope this does not scare you out of doing it, it is really not as bad as it sounds although it is somewhat critical to do properly in order to have a quiet rear. Some people and even gear manufactures claim some noise is normal, I don't agree. I think the gear manufactures say that to cover their butts. I have never had any rearend make noise after I have set it up correctly. Let us know how it goes and maybe some more people will chime in here and cover a few things I may have left out but that is pretty much a summary of what is involved. Hope this sheds some light on it for you. Larry.

 

Oh I re-read your post and sounds like you need to know what tools are involved.

Here is what I use:
Pinion Depth Gauage (to set pinion depth)
Inch pound torque wrench (to check preload on pinion bearings)
Dial indicator with magnetic base (set back lash)
ft lbs. Torque wrench (to torque down caps on center section and also to torque ring gear to center section)
Hydraulic press ( to press pinion bearings on and off)
You can skip the press if you do the old back yard trick of heating the bearings up in the oven, then they usually slide right onto the pinion.
I also have an extra pinion bearing with the inside dia. machined slightly to slide on easily, I use this bearing while setting pinion depth as it will have to come off a few times before proper depth is found. When I have found it I then go ahead and install the new bearing with crush sleeve and tighten pinion nut until proper inch pound reading is found.
Just a few things I also thought of, been a few months since I have set one up so things are coming to mind slowly Hope this helps, Larry.

 

what he said, plus i've got a few tools i made, something for a datum since i use a depth mic, something to hold the pinion yoke, mostly it's a piece of steel with a hole or two in the right place

 

Good tip... never thought of that, thanks!

Tom, you do need a dial or beam-type torque wrench for checking preload. Like Larry said, an in-lbs wrench that reads on a small scale. You really need 1 or 2 in-lb increments. The specs are spread enough on a 10-bolt that a 5 lb increment wrench could work, but you're better off knowing exactly what the turning torque is instead of estimating.

If you can get/make a bar to hold the pinion yoke/companion flange down like Ede mentioned then you're set. Otherwise just get a big-*** pipe wrench and wedge it against something hard.

Have fun.

Scott

 

Thanks for the info Larry/ede/Scott!

I do have a beam-type torque wrench but it's old, don't know how accurate it is anymore. Is there any advantage between dial-type or beam-type besides "easy to see the dial"?

Ya know I completely forgot about the bearing on the pinion- I guess I could pick up a small press (or weld a frame up for one) but I guess I'd need some special way to cradle the pinion gear?

What about this... I really "only" have to replace the posi unit. It's actually an Eaton Gov-lock that shredded itself. The gears inside are 3.73's so they're going to stay. The rear doesn't leak at all; what do I need to just swap the dead center out with a new Auburn posi?

Could it be as simple as pulling the old diff, installing the new, and checking the setup with my dial gauge/mag base?

I don't want to just bolt in the new posi and "go" without checking the setup. Luckily the rear is off the car right now so it makes life a little easier.

 

To answer your first question about the pinion bearing, they do make a tool that cradles the pinion bearing so you can stick the pinion gear in the press and remove the bearing without damage (usually) most good tool places sell it. I also use it to remove bearings from axles, center sections, rebuilding transmissions etc... so this tool is very usefull, so is the press. An easy way to install the pinion bearing is to heat the bearing up in the oven for about 1/2 hour at 250-300 dregrees and then they usually fall on. This is an old back yard trick but affective. I usually have to take off the bearing a few times until I get the pinion depth correct and the shims are behind this bearing, for this operation as I mention before I have a bearing that I have the center section hogged out slightly to slip on easily, then after I have the correct amount of shims, I install the new bearing perminantly. Then check pinion depth one more time to make sure everything stayed the same.
As for just swapping out the center section that will be much easier for you. If your gears are fine there is no need to remove the pinion. If your center section is original and never been removed it will have cast iron shims, one on each side. Sometimes when you install the new carrier along with new side bearings you may get lucky and be able to use the old cast iron shims, you will have to check back lash with your dial indicator and magnetic base, I would check it before removal and see what you have first. Sometimes with mileage it will be rather large. Lets say .011, When you reinstall the new carrier with the cast iron shims and new bearings check your back lash, you might get lucky and be right where you were, I rarely have that happen though. Usually you will need a shim kit and you will have to move shims around side to side until proper back lash is found, then you have to add about .004 to .008 preload on the bearings by adding shims to each side while at the same time keeping the proper back lash. I would have to look at the GM book to see what the factory setting was for your particular rearend, it is usually somewhere around .006 at its tightest and maybe as loose as .010 or .012, again check the book for the specs, or if you have aftermarket gears they may have there own specifications. I like to set mine on the tighter side of the spectrum, leaves less room for shock loads and makes less noise also. Hope some of this helps, let us know how it turns out. Larry.