Hello Listers:
I copied part of a message and it's reply below
However, I'm not an axle expert in any way shape or form
Thgerefore, I write my thoughts and questions not as ananswer but as a huge
puzzlement on my part?
Now,
Snip from original question
> Is it weird that My front axle, Dana 25, has a 39/8 tag and my rear axle,
> Dana 44, has a 44/9 tag? It seems to work fine in 4wd but I haven done
much
> since my front drive shaft is worn out.
Then came a "reply" that the ratioas were the same so...???
"when you do the math, the ratios are the same." !!!!
While this is true ...and here are the tooth count & ratios,
[Front, 39/8 = 4.88 / Rear, 44/9 = 4.88]
Then, the wheels would seem to spin at the same rate.
Yes ?
Now, Here is my question....
Wouldn't the output of the transfer case drive shafts absolutelty turn at
the same speed ?
That answer is Yes !
Note however, that the Pinion Teeth Ratios are different per revolution .
Because, there is one "less" tooth per revolution... then, one diff. never
got to complete one pinion revolution before the other diff started it
second revolution ...correct???
Now, multiply that by hundreds of revs per minute
Therefore, one differential is not receiving the full turn and consequently
may never get to "output the same ratio" as the other ???
I imagine, that you would possibly see tires, gouging & scrubbing & skipping
and hopping ?
At any moment ...one diff is trying to be pushed or pulled by the other.
This may not matter if you are sure that the vehicle is always running on
wet muddy surfaces allowing the tires to be the final slipping point.
Then, begs the question what happens when the vehicle hits solid ground
. and seeing that the pinions are "Trying" to travel at "different speeds"
( but they cant) ...then maybe, just maybe, this is why the drive shaft
has become "worn out" ...and who knows what else is about to fail
This intrigues me.
Or , are all 4x4 diffs identical or always different at their inputs??
It beats me.?
Any Differential gurus out there ?
Regards from Rob. Pearson
Upstate, NY
a small straggly flock of jeeps.
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