Technical Differential expert's ! Weird pinion gear

As soon as I read weird failure I thought what you described that happened to a guy from work that had about the same year truck..I don't think he found the problem at the gear, just changed the axle and claimed it was ok..

 

How does a square gear get turned by (/) a triangle gear ? Impossible right ? Wrong. Jim, your continued hint's of the common denominator "3" is the clue that I failed to understand and why I was looking at my gears as a full on hunting gear set and not a partial as you clearly put up first. Then I failed once again when you threw the word "Partial" out there again. But why the term partial ? Why ? Well only simple physics's would explain how 3:25 gears can be viewed microscopically as a square pinion turning a triangle ring gear and why the variation of back lash. And where's just some of the math that proves this. 3.25 x 4 = 13. Now divide 39 (ring gear tooth count) by every third tooth on the pinion (12 tooth) which is exactly 90 degree's looks like this. 39/3=13. The number 13 now is a key clue here. Because if one where to take the time and turn the pinion so that the ring gear goes around exactly 13 times the one pinion tooth that set out on it's journey from home would go around the ring gear for 13 revolutions would now be back home to where is started. This is why "partial" is implied and how one fit's a square beg in a triangle shaped whole. "Math, a human invention to answer the unexplainable". Now I know what the answer is to why only 4 pinion teeth were making contact on a much broader level. Yes guy's I'm an over "Thinker" that's not satisfied with just a simple solution.

 

I love car problems that make us lose sleep

 

Yawn...But I still think a bad pinion bearing...

 

Funny you say that Jim. At 2 a.m. this morning driving back home from seeing family hrs. away and the girlfriend asleep next to me This is what started the whole chain recreation. Number's going thru my head. 4, 3, 13, 12 39, 13 39 What The ! 3.25 x 4 is 13 ! And that's how I went to bed and woke up with what I posted.

 

As I've said people believe what they think is right. Explain then your theory then when this unit I'm working has all new bearing's ?

 

Weird gears in unison

 

New does not always prove good..You believe [people believe what they think is right] because they are new they are good...I believe that they can be bad even though they are new..Things happen...Did you check run out at 3rd brg or run out of ring gear? I believed a set of push rods were good because they came with the cam kit...Inside of the 20 minute cam break in the ball ends pounded flat; that could have been ugly...

 

Yes. Any other question's I may answer for you ? You guy's are really funny. If you guy's could, you'd have me drink a cup of poison hemlock just as Meletus did to Socrates just because he didn't like what he heard.

 

I like my 57-63 Pontiacs. 2.56's thru 5.13's...

 

Today I will be numbering 13 teeth on the ring gear with numbers 1-13 and place the pinion marking into each of those numbers with the original pinion shim back in place. This will make for a basic approach to a what would be termed as applied science. I'll report back soon enough.

 

PRINT and hang on MANCAVE wall...

NON.HUNTING GEAR SET
In a non-hunting type gear set, any
one pinion gear tooth comes into contact
with only a few ring gear teeth.
In this type, only one revolution of
the ring gear is required to make all
possible tooth contact combinations.

HUNTING GEAR SET
In a hunting-type gear set, anyone
pinion gear tooth comes into contact
with all drive gear teeth. In this type,
several revolutions of the ring gear
are required to make all possible gear
combinations

PARTIAL NON.HUNTING
GEAR SET
In a partial non-hunting type gea
set, anyone pinion tooth comes into
contact with only part of the ring
gear teeth, but more than one revolution
of the ring gear is required to
make all possible gear tooth combinations.
Tooth to tooth pattern uniformity
will usually be in between the hunting
and the non-hunting patterns.
Partial non-hunting gear set patterns
will usually be less uniform than
hunting gear set patterns, but more
uniform than non-hunting gear set
patterns.

 

That's all well and good but there are some that do not understand what all that means.

 

Yup. Like I told my little bro after he built his Currie/Mosier? 9" (Camaro LS3)... Its stronger than my Pontiac 9.3 because its ALL aftermarket fixed

 

Here's what I've found out so far this morning before taking anything apart. It show's how theory vs applied theory differ's. I had stated before that my math said there would be 13 turn's of the ring gear so the pinion tooth would be back to home. Wrong ! It's ring gear 4 turns and pinion 13 turns. This is interesting because my original question was why are there 4 teeth that are proud on my pinion. This would also lead away from any bearing issue's doing this.

 

So you have to take the best average of the pattern when setting backlash. And look at the pattern in between the partial non hunting gears for it. Bit confusing but it works if those teeth have a slightly different cut on them.

 

That about sums it up in a nut shell on what I have to do now. Had I known what Jim shared at the beginning of this thread I would have been done a long time ago.

 

in addition to and
so
a
http://www.mustang.org.au/technicals/66/4 - rear axle.pdf

 

Think of the setup as two triangles... one just sideways... if you try to push one triangle too far forward into its triangle hole it gets pinched and cant make it through... set it back and its free. Thats how i think of it because they are curved teeth. It would be easier if the teeth were straight on straight but they would be weak. Think the arc of the teeth make them push and pull much stronger. Anyways you cant shim it side to side only front to back right?

 

Your on the right track about high's and low's as the gears rotate however this is a square turning a triangle (exaggerated of coarse). There shouldn't be any shimming needed other than putting back the original pinion shim back. Just find the sweet spot out of 13 position's and set the backlash.

 

Oh yeah! I meant backlash!!! I just forgot the term on the spot.
You got this one licked though.
Is your avatar pic the car your working on?

 

No. It still has it's original early 8.2 in it. The 9" is for my girlfriends 32 Ford pick up which all ready had a 9" housing in it before I got to it.

 

The final score is in Guy's. Some Monday's just are not worth getting up for sometimes. But not this Monday ! Complete luck was in my favor finally. I found the darn mark on the ring gear that seemed to not be there. I had all ready numbered 9 valleys on the ring gear and as I went to write 10 my flash light caught a little glimpse of a shiny spot where I was going to write. At first it looked like a nick and as I looked closer there was another one on the other corner of the stair step cut of the ring. "No way ! I picked the right 3rd of the ring to number in my hopes to find home" I thought. Then it got even better because they won't nick's at all. They were radius'd like if a fine grit 4" cut off wheel had made them but to damn small, no to f'n tiny for ageing eye's to see. The rest as you've all probably gathered by now is that everything fell into place. And it did. After putting back the original pinion shim I now can hear all the pinion teeth rub against the ring gears teeth with no lube. Did a back lash check and adjustment followed by a pattern check. All good. End of story. One last note. No body questioned how much shim I used to get all the teeth to mesh last week. I say this because I knew I was on the wrong approach of correction and I needed to find the right fix. Anyone care to tell the class what happen's when the pinion is shimmed to far away from the ring gear ? Hint, "coast".

 

so, you found the timing marks?

 

Sure did Jim. Thanks for being the stand back and watch where he goes type of teacher. I've never liked pushy know it all's as you've probably gathered by now.

 

An idol of mine. The only physicist to have the ball's to not where eye protect's on the Manhattan Project when they set off the first bomb in New Mexico. Also the person who figured out why the Space Shuttle exploded in the mid 80's using a "C" clamp to demonstrate. https://socialbridge.files.wordpress.com/2014/11/richard-feynman-quotes.jpg

 

I like his safe cracking exploits.