8 3/4 ring and pinion swapout

[mopower440]

so i have a 741 case 8 3/4 rear that has a 3.23 suregrip (clutch style). I have purchased a 3.73 ring and pinion set along with all new bearings. This will be my first ring and pinion swap. I have been watching some videos on how to do it and am confused on a few things..First is the shimming of the pinion, is the reasoning to get the correct drag on the pinion or to get the depth into the ring gear correct? Next, being the bearings are pressed onto the pinion shaft, if i put it together and it needs more or less shims, is it going to ruin the new bearings by removing them and pressing them back on several times over until the shims are correct?? Im assuming that since this is a whole new ring and pinion set that the oem shims currently in it probably arent going to get it correct like it could be if i was just re-using the original ring and pinion..

 

[Illahe]

so i have a 741 case 8 3/4 rear that has a 3.23 suregrip (clutch style). I have purchased a 3.73 ring and pinion set along with all new bearings. This will be my first ring and pinion swap. I have been watching some videos on how to do it and am confused on a few things..First is the shimming of the pinion, is the reasoning to get the correct drag on the pinion or to get the depth into the ring gear correct? Next, being the bearings are pressed onto the pinion shaft, if i put it together and it needs more or less shims, is it going to ruin the new bearings by removing them and pressing them back on several times over until the shims are correct?? Im assuming that since this is a whole new ring and pinion set that the oem shims currently in it probably arent going to get it correct like it could be if i was just re-using the original ring and pinion.

Take an inner pinion bearing and hone it so it just slip fits over the pinion shaft and set the pinion depth. Place the outer bearing and yoke on the pinion, then assemble and check your pattern.

Once your good press the "new" bearing on the pinion and re assemble.

 

[RustyRatRod]

The shims are to set the pinion gear depth in relation to the ring gear.

Yes, if you aren't careful or don't have the right tools (A press and bearing separator) you can and in all likelihood mutilate bearings.

What I do is carefully remove the old large pressed on large pinion bearing. I then hone the inside of that bearing to a slip fit on the new pinion shaft. Then I start fitting shims and find my correct pinion depth. Once I find that, I remove the old bearing, leave the correct shim in place and press the new bearing on. The differences between the used and new bearing will be very minimal and will have a negligible effect on the pinion depth.

 

[RustyRatRod]

Take an inner pinion bearing and hone it so it just slip fits over the pinion shaft and set the pinion depth. Place the outer bearing and yoke on the pinion, then assemble and check your pattern.

Once your good press the "new" bearing on the pinion and re assemble.

Ya treed me! lol

 

[mopower440]

The shims are to set the pinion gear depth in relation to the ring gear.

Yes, if you aren't careful or don't have the right tools (A press and bearing separator) you can and in all likelihood mutilate bearings.

What I do is carefully remove the old large pressed on large pinion bearing. I then hone the inside of that bearing to a slip fit on the new pinion shaft. Then I start fitting shims and find my correct pinion depth. Once I find that, I remove the old bearing, leave the correct shim in place and press the new bearing on. The differences between the used and new bearing will be very minimal and will have a negligible effect on the pinion depth.

sounds good! What are you guys using to hone the center of the old bearing out? Also, when i use the old honed out bearing to set the pinion depth, im assuming i have to put the complete unit together, set the backlash and use the gear marking compound to be sure that pinion depth is correct, and once it is correct, tear it all back down and press on the new pinion bearing. OR, am i only assembling the pinion into the housing and getting the resistance setting correct on the pinion using the inch pound wrench and then installing the new bearing and THEN installing the ring gear and doing the backlash? Im asking because on the videos ive watched, it seems like they do it separately..They shim the pinion until the resistance while spinning it is correct, and then they are done with the pinion, THEN, the install the carrier and set the backlash and use the marking compound to check it all..Ive never seen any of them assemble it completely, check it with marking compound and then tear it all back down to remove or ad shims to the pinion..its like they always get the correct pattern by just changing the adjustment on those side bearing adjusters.. Just asking so i do this correctly so bear with me and thanks for any and all help!

 

[RustyRatRod]

I use a small three stone cylinder hone. It takes a little time, but it works.

 

[jas0162]

Ive been through several 8 3/4 gear changes over the years and have found if you use the shim or shims from your old gears in the same housing your pinion depth will most likely be good, if it was good before. That being said, the honed bearing can save time.

 

[Oldmanmopar]

Ya treed me! lol

He was using a trans brake. You were foot braking.

 

[RustyRatRod]

He was using a trans brake. You were foot braking.

 

[Sterling]

In the 741, there are shims to set the pinion bearing preload, and shims for the pinion depth. I would remove the old bearing from the 3.23 pinion, and start with the shim under the bearing for pinion depth. And if you don't ruin the bearing removing it, you can hone the old bearing and use that for mock up.