Questions during the assembly of a 12-bolt

[derekf]

I'm in the process of swapping the 2.73 open with 4.10s and a TrueTrac.

I've run into some cases where I don't know what I'm doing (ok, to be fair I don't know what I'm doing with any of this, but this is a new level of lost).

1. From the Richmond Gear instructions:

"Backlash settings are marked on the outside diameter face of the ring gear (illustration)" and "Pinion depth settings are marked on the face of the pinion (also illustration)".

I don't know that I can read what it says:



This is the pinion depth - maybe starts with a 2?

and this is the backlash suggestion:



Surely that's not .150?

The second issue I ran into was "Okay, I can't read these. Let's try this Jegs Pinion Depth Checker, and see what IT thinks we've got with the old shim."

Step 2 in the Jegs instructions: "Zero the dial indicator using the supplied checking block and appropriate extension.. slide into collet until dial reads zero, then tighten."

The handy chart on the back of the instructions says 12 bolts are 4.670", so the 4.3" extension seems appropriate.



It doesn't bottom out in the checking block. Hell, I can skip inserting the collet and it still doesn't bottom out. I'm sure I'm doing it all wrong but the internet is filled with people complaining about these instructions and I didn't find anyone actually explaining it (except a reference to an angelfire page that is no longer available)

The third issue is probably not an issue. I honed out the old inner pinion bearing so it's a slip fit. When I do the pinion depth checking, do I need to have the front bearing seated as well or just let it ride on the inner?

[derekf]

Both of these questions are resolved by deciding that I don't care what the depth gauge says, I'll use the pattern.



HOWEVER.... the old carrier had a .240 and a .235 shim in there; should I be concerned that I can only fit about .375 worth of shims in with the new (truetrac) carrier?

[chevelletiger]

Derek,I did a tru trac,about 2yrs back
I really had trouble setting up Richmond gears and bought a set of 3:73 us gear set.
Set up went smooth.
I used a t&d machine pinion depth tool,and made a case spreader to put preload on the carrier bearings,also I'll look it up,and there's some math on figuring the pinion depth #

[chevelletiger]

The tool in action.
If you give me a deposit on it,I could let you borrow it,also if you dont have one buy an inch pound beam style torque wrench,for setting pinion bearing preload.
Phil

[chevelletiger]

Btw,if you download t&d machines deluxe pinion depth tools instructions,go to the bottom page it describes how to get the pinion depth #
You subtract the pinion head thicknes(PHT),From the Master housing dimension(MHD)
Check it out.

Torque Specifications:
Pinion Preload New:P: 14 to 19 in-lbs
T: 13 to 15 in-lbsPinion Preload Reused:P: 6 to 8 in-lbs
T: 6 to 7 in-lbsRing Gear Backlash:.006" to .010"Ring Gear Bolt Torque:55 ft-lbsCarrier Bearing Caps:60 ft-lbs