Changing pinion and ring gear.

Removed .093 inch thick "selective" spacer between old pinion gear & immediate bearing.

Tempted to put it on new pinion after reading procedure to establish spacer thickness requirement from shop manual using tool consisting of arbor, spacer block, etc...

Shop manual indicates correct spacer could be between .084 and .100.

Has anyone come up with a method to determine the correct thickness prior to pressing on the pinion bearing?

Am I doomed to trail and error method involving removal (and destroying) the bearing multiple times?

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1965 Dart 125k, 225, Carter BBD Super Six, 2 1/4 single exhaust., sbp manual scare-bird front disc, 7 1/4 rear 2.94 sure grip, 15 x 4.5 wheels, 833 OD with hyd. throw-out bearing, electric fan, ram air/heated air, Accusump.

You are "doomed"...
The only thing that makes this less "painful" is a set-up bearing. one the easily slides on & off the pinion... so you can find the correct gear "mesh" (contact pattern) with-out a lot of "press work".
(Take your old bearing to a machine shop and have them hone-out the ID )
DD

Good idea opening up a testing pinion cone bearing ID to speed up (but not be speedy) the trial and error testing for tooth contact pattern with different selective spacers.

Thanks

Don

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1965 Dart 125k, 225, Carter BBD Super Six, 2 1/4 single exhaust., sbp manual scare-bird front disc, 7 1/4 rear 2.94 sure grip, 15 x 4.5 wheels, 833 OD with hyd. throw-out bearing, electric fan, ram air/heated air, Accusump.

Pinion Temporary Bearings ID opened up just enough for tooth contact study.
Worked nicely thank you!!

With Backlash at mid range of factory specs
(.004 to .007 the actual is .0055.)
Drive side Tooth pattern contact area nearly centered but slightly high.
Tooth pattern on coast side however is slightly low & near toe.

Knowing:
1)backlash can stand slight loosening
2)for differential bearing preload I had used .012 instead of .010
3)coast needs to be raised and more centered

should I reduce differential bearing passenger shim .003
(side away from gear)
to simultaneously open up backlash while pushing gear toward pinion?

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1965 Dart 125k, 225, Carter BBD Super Six, 2 1/4 single exhaust., sbp manual scare-bird front disc, 7 1/4 rear 2.94 sure grip, 15 x 4.5 wheels, 833 OD with hyd. throw-out bearing, electric fan, ram air/heated air, Accusump.

I prefer setting up a little on the tight side of a range, figuring it will loosen with wear, and will still be within factory tolerances after it does so. I've achieved a great many trouble-free miles using this rule of thumb.

For what it's worth, I've heard gear professionals say you cannot adjust by contact pattern alone, that you must set the pinion depth (using $$$ tool) based on whatever is stamped on the pinion, and then fine-tune the pattern. But for the life of me I can't figure out why a good contact pattern is not sufficient. Anyone know?

- Erik

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Lots of early Valiants and Barracudas have crossed my path.
Also a handful of other toys for variety now and then.

Had to drop pinion selective spacer (closest to pinion gear) to get a substantial coast ring gear pattern improvement.

Unfortunately the pinion bearing preload climbed above 100 in lbs.

So the pinion bearing spacer nearest the driveshaft companion flange needs to be thicker.....from .094 to nearly .112.

The ring gear/pinion kit contained what appears to be a crushable washer almost .5 inch thick ......I'm skeptical it will shrink to .112.

Have others seen that spacer (approx. 1 7/16 OD 1 3/16 ID) in thicknesses nearing .112? Any one have any? Or is there something about crushable washers that needs learning for me?

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1965 Dart 125k, 225, Carter BBD Super Six, 2 1/4 single exhaust., sbp manual scare-bird front disc, 7 1/4 rear 2.94 sure grip, 15 x 4.5 wheels, 833 OD with hyd. throw-out bearing, electric fan, ram air/heated air, Accusump.

Finally got things right on drive/coast patterns and pinion preload but it was ugly getting there.
The sure grip rear is quiet now but I wish I had known from the beginning that the new pinions are cut differently than the old
It would have saved a long crawl with different pinion shim thicknesses & several machine shop visits.

If you put an old pinion next to a new replacement one you will find that the bearing stop that determines pinion preload is machined to a different location by almost 7/16!!
So instead of the original .094 thick pinion shim it climbs way thicker before getting decent bearing preloads on the pinion.
I think they do this to switch over to a crushable shim design.

Since I don't trust the idea of a crushable shim staying constant over time I had a set of shims machined to get the preloads decent
How many times you get to torque the pinion nut to 240 ft lbs must be a good physical health exercise but not mental???

Recommend you don't watch the clock when assembling one of these.

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1965 Dart 125k, 225, Carter BBD Super Six, 2 1/4 single exhaust., sbp manual scare-bird front disc, 7 1/4 rear 2.94 sure grip, 15 x 4.5 wheels, 833 OD with hyd. throw-out bearing, electric fan, ram air/heated air, Accusump.