8 3/4 Center Section Tear Down

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Rocket

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A couple questions before I tear into the 8 3/4 myself.

The factory service manual suggests measuring side pay and runout before taking the center section apart. For those of you in the know is this necessary?

Any special tools needed to take the center section apart? I have the basic hand tools, compressor and bearing removal tools.

Thanks
 
Nothing special at all for taking it apart. You will need a spanner wrench to adjust the side bearing adjusters and a dial indicator to check the run out and backlash. That's the only special tools needed.
 
I'd measure backlash and preload before you take it apart, that way you have a guide for reassembly. Like said above, you'll need a dial indicator for that. Changing gears? you'll need a tool to set pinion depth. Don't lose those shims. X2 on the spanner for the bearing cups. Hard to do it without one. Randy's has 'em if you need one.

You'll need fairly specific torque wrenches for when you put it back together - one burly enough that will allow you to set pinion nut torque and one for pinion turning torque. The pinion nut is over 200 ft. lbs. and turning torque requires an inch pounder.

Something to hold it in place on a stand or bench would be good too.
 
You need a rotating torque torque wrench to properly set the pinion bearing preload. Get that wrong and the new gears will be junk before the first break in is done.
 
Taking measurements before disassembly would be particularly useful if you're going to reassemble the same gears.

I made a spanner wrench with a piece of tubing and a couple of bolts.

Which center section do you have? (741, 742, 489) Some are slightly easier to set up.
 
The center is a 741. I will likely disassemble the unit, rebuild the limited slip unit with new clutches, clean and paint the housing and have a local shop to the reassembly and final adjustments. This is why I was wondering if I needed to record the measurments before I tore it down. I will certainly retain the original spacers on the pinion. I plan to use th esame gears.
 
If your having somebody else do the carrier installation you probably don't need to worry about doing the before measurements. An experienced shop should have no problem setting it up. BTW: You know you have to properly align the splines in the 3rd member when you assemble it right? I use an old set of axles cut down to about a foot long to do mine but you can use full length axles but will probably need help as it will be awkward to hold. Also the bolts holding it together are left hand threads.
 
I will follow the shop manual when reassembling the sure grip. If I need to align the splines then as you suggest I will need to rig something up to do it properly.
 
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