Pinion depth setting

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mbaird

mbaird

mbaird
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Instead of buying a $300 pinion depth tool couldn’t I just use a piece of machined flat stock mounted to the saddles with a threaded hole with fine threaded rod and measure the distance to the top of the pinion . then shim accordingly?

I could test it on a factory mounted pinion to verify that the saddle is centered on the differential bearing…
 
300 bucks? My GAWD, was it solid gold? I use these. I have a few for popular rear ends. They work well. I think your method would be fine. Just remember, the numbers stamped on the end of the pinion are there only for a guide to get you in the ballpark. The gear pattern is the deciding factor.
Pinion Depth Tool
 
Yes, you can use a piece of precision ground flat stock and a depth micrometer. Instructions start at 33:05.
 
RustyRatRod said:
300 bucks? My GAWD, was it solid gold? I use these. I have a few for popular rear ends. They work well. I think your method would be fine. Just remember, the numbers stamped on the end of the pinion are there only for a guide to get you in the ballpark. The gear pattern is the deciding factor.
Pinion Depth Tool
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I went to link and watched video but it was worthless. T rr ting to visualize exactly how its used . Same as flat stock I assume but you subtract a certain amount?
 
which rear end are you working on? 8 3/4 bores are not centered, dana's are centered
 
But I am hoping that if I measure a factory installed pinion first I can establish the offset. I assume it would be the same for all 742 cases .
 
It’s pretty amazing that being off .010-.020 makes difference on how the gears run considering the overall size of the teeth .
 
Alright. If it was all set up I could have told you a trick.
 
How did the factory get them correct if the cases weren’t all same dimensions for any given case number ? The bottom of saddle to pinion base that is… I have watched an old Chrysler training vid on the factory procedure and I thought they had mentioned that they were . Seemed like the pinion gears were the variable .
 
There is a stamped number on the pinion then check the number on the new one. Example, *.003 on old one and new one has +.006 subtract .006 - .003 = .003 so subtract .003 on the shims. It has been like a million years so it could be add just check one out but I think you would subtract.
 
LO23M8B said:
There is a stamped number on the pinion then check the number on the new one. Example, *.003 on old one and new one has +.006 subtract .006 - .003 = .003 so subtract .003 on the shims. It has been like a million years so it could be add just check one out but I think you would subtract.
Click to expand...

That works great till you get an aftermarket pinion, they measure by actual depth.
I copied the dealership tool, and made the carrier bearing sizes in chev, Ford, Dana, so it works on all diffs, including Toyota.

The small square flat piece is exactly 0.500" (1/2") to transfer the end of the pinion gear over to the center of the case, where the machined "flat" center of the cross shaft.
( Hope that make sense)


 
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Inertia said:
That works great till you get an aftermarket pinion, they measure by actual depth.
I copied the dealership tool, and made the carrier bearing sizes in chev, Ford, Dana, so it works on all diffs, including Toyota.

The small square flat piece is exactly 0.050" to transfer the end of the pinion gear over to the center of the case, where the machined "flat" center of the cross shaft.
( Hope that make sense)

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I thought all pinions were measured from machined faces on bottom to top one . Then you measure the difference between old and new .
 
Not sure I can answer that, 1968, my mentor taught me adding according to the few thou etched in the pinion, ( ala L023M8B post) - then we moved to universal shop, and all the aftermarket gears came with depth from center, made the tool to work on all.
 
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mbaird said:
I went to link and watched video but it was worthless. T rr ting to visualize exactly how its used . Same as flat stock I assume but you subtract a certain amount?
Click to expand...
Correct. It's an industry wide method.
 
mbaird said:
It’s pretty amazing that being off .010-.020 makes difference on how the gears run considering the overall size of the teeth .
Click to expand...
.010" is a country mile regarding gear pattern. It makes a huge difference. I agree, it's hard to get your head around.
 
Inertia said:
As Rusty mentioned, 3 thou can move the pattern/contact quite a bit .
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Yes I am aware of that . My point was that you wouldn’t think even .010 would make a difference on gears this big bathed in 70 weight gear oil .
 
mbaird said:
It’s pretty amazing that being off .010-.020 makes difference on how the gears run considering the overall size of the teeth .
Click to expand...
It’s the hypoid angle combined with the bevel angle of the ring gear.
That whole dynamic changes tolerance allowance down to less than .005 of an inch. Pretty well turns it into a game of “its right!” vs. “every other possible setting away from correct.”
 
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