Pinion angle, revisited...

Ok, I got under the TJ and dropped the pinion a little (adjusting the UCAs
accordingly). I still have vibration at 55+. This weekend I'll probably drop
it a little more to see if that does the trick... I guess the option is put
spacers on the t-case skid, but it doesn't seem like I should have to what
with the CV shaft and all...

Is there something I'm missing?
n.

Making sure you know that the pinion shaft needs to be pointed directly
at the t-case output shaft. Just make sure its angle is not above the
driveshaft either. 1-2 degrees under that of the driveshaft's angle is a
good angle to aim at to counteract the minor effects of axlewrap on a
coil spring TJ.

Jerry

Nathan Otis wrote:
> Ok, I got under the TJ and dropped the pinion a little (adjusting the UCAs
> accordingly). I still have vibration at 55+. This weekend I'll probably drop
> it a little more to see if that does the trick... I guess the option is put
> spacers on the t-case skid, but it doesn't seem like I should have to what
> with the CV shaft and all...
>
> Is there something I'm missing?
> n.
>
>

--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.cox.net/jerrypb/

Thanks Jerry... I'll probably drop the angle just a little more this
weekend. I did know the pinion needs to be pointed at the output, but it's
tough to see exactly where everything is pointed...
n.

"Jerry Bransford" > wrote in message
news:dn7Yd.70929$Tt.5232@fed1read05...
> Making sure you know that the pinion shaft needs to be pointed directly at
> the t-case output shaft. Just make sure its angle is not above the
> driveshaft either. 1-2 degrees under that of the driveshaft's angle is a
> good angle to aim at to counteract the minor effects of axlewrap on a coil
> spring TJ.
>
> Jerry
>
> Nathan Otis wrote:
>> Ok, I got under the TJ and dropped the pinion a little (adjusting the
>> UCAs accordingly). I still have vibration at 55+. This weekend I'll
>> probably drop it a little more to see if that does the trick... I guess
>> the option is put spacers on the t-case skid, but it doesn't seem like I
>> should have to what with the CV shaft and all...
>>
>> Is there something I'm missing?
>> n.
>
> --
> Jerry Bransford
> PP-ASEL N6TAY
> See the Geezer Jeep at
> http://members.cox.net/jerrypb/

Jerry,
How would one go about point the pinion shaft directly at the tcase output
shaft?

I think I would try to use a string that followed the plane of the pinion
shaft, and make sure I didn't break the plane by pulling the string at an
angle. But, how would one find the plane of the pinion shaft to establish
the line for the string?






"Jerry Bransford" > wrote in message
news:dn7Yd.70929$Tt.5232@fed1read05...
> Making sure you know that the pinion shaft needs to be pointed directly at
> the t-case output shaft. Just make sure its angle is not above the
> driveshaft either. 1-2 degrees under that of the driveshaft's angle is a
> good angle to aim at to counteract the minor effects of axlewrap on a coil
> spring TJ.
>
> Jerry
>
> Nathan Otis wrote:
>> Ok, I got under the TJ and dropped the pinion a little (adjusting the
>> UCAs accordingly). I still have vibration at 55+. This weekend I'll
>> probably drop it a little more to see if that does the trick... I guess
>> the option is put spacers on the t-case skid, but it doesn't seem like I
>> should have to what with the CV shaft and all...
>>
>> Is there something I'm missing?
>> n.
>
> --
> Jerry Bransford
> PP-ASEL N6TAY
> See the Geezer Jeep at
> http://members.cox.net/jerrypb/

An angle finder placed on the output shaft's u-joint gives the t-case's
output shaft angle. Then the plane of the axle's pinion angle can be
found with the angle finder placed at the rear of the axle housing on
one of the two circular points which is perpendicular to the pinion
shaft. Since the angle finder has two flat planes 90 degrees apart from
each other, the angle finder can be rotated so it can be at the same
angle it was when measuring the t-case output shaft. Then move the
pinion up or down until it's at or 1-2 degrees under that of the t-case
output shaft. At least that is how I get a pretty precise measurement
on them.

Jerry

Jeff Strickland wrote:
> Jerry,
> How would one go about point the pinion shaft directly at the tcase
> output shaft?
>
> I think I would try to use a string that followed the plane of the
> pinion shaft, and make sure I didn't break the plane by pulling the
> string at an angle. But, how would one find the plane of the pinion
> shaft to establish the line for the string?
>
>
>
>
>
>
> "Jerry Bransford" > wrote in message
> news:dn7Yd.70929$Tt.5232@fed1read05...
>
>> Making sure you know that the pinion shaft needs to be pointed
>> directly at the t-case output shaft. Just make sure its angle is not
>> above the driveshaft either. 1-2 degrees under that of the
>> driveshaft's angle is a good angle to aim at to counteract the minor
>> effects of axlewrap on a coil spring TJ.
>>
>> Jerry
>>
>> Nathan Otis wrote:
>>
>>> Ok, I got under the TJ and dropped the pinion a little (adjusting the
>>> UCAs accordingly). I still have vibration at 55+. This weekend I'll
>>> probably drop it a little more to see if that does the trick... I
>>> guess the option is put spacers on the t-case skid, but it doesn't
>>> seem like I should have to what with the CV shaft and all...
>>>
>>> Is there something I'm missing?
>>> n.
>>
>>
>> --
>> Jerry Bransford
>> PP-ASEL N6TAY
>> See the Geezer Jeep at
>> http://members.cox.net/jerrypb/
>
>

--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.cox.net/jerrypb/

Well.... That sounds _pretty_ percise ;-)

Thanks,
n.

"Jerry Bransford" > wrote in message
news:5T8Yd.70933$Tt.14108@fed1read05...
> An angle finder placed on the output shaft's u-joint gives the t-case's
> output shaft angle. Then the plane of the axle's pinion angle can be
> found with the angle finder placed at the rear of the axle housing on one
> of the two circular points which is perpendicular to the pinion shaft.
> Since the angle finder has two flat planes 90 degrees apart from each
> other, the angle finder can be rotated so it can be at the same angle it
> was when measuring the t-case output shaft. Then move the pinion up or
> down until it's at or 1-2 degrees under that of the t-case output shaft.
> At least that is how I get a pretty precise measurement on them.
>
> Jerry
>
> Jeff Strickland wrote:
>> Jerry,
>> How would one go about point the pinion shaft directly at the tcase
>> output shaft?
>>
>> I think I would try to use a string that followed the plane of the pinion
>> shaft, and make sure I didn't break the plane by pulling the string at an
>> angle. But, how would one find the plane of the pinion shaft to establish
>> the line for the string?
>>
>>
>>
>>
>>
>>
>> "Jerry Bransford" > wrote in message
>> news:dn7Yd.70929$Tt.5232@fed1read05...
>>
>>> Making sure you know that the pinion shaft needs to be pointed directly
>>> at the t-case output shaft. Just make sure its angle is not above the
>>> driveshaft either. 1-2 degrees under that of the driveshaft's angle is a
>>> good angle to aim at to counteract the minor effects of axlewrap on a
>>> coil spring TJ.
>>>
>>> Jerry
>>>
>>> Nathan Otis wrote:
>>>
>>>> Ok, I got under the TJ and dropped the pinion a little (adjusting the
>>>> UCAs accordingly). I still have vibration at 55+. This weekend I'll
>>>> probably drop it a little more to see if that does the trick... I guess
>>>> the option is put spacers on the t-case skid, but it doesn't seem like
>>>> I should have to what with the CV shaft and all...
>>>>
>>>> Is there something I'm missing?
>>>> n.
>>>
>>>
>>> --
>>> Jerry Bransford
>>> PP-ASEL N6TAY
>>> See the Geezer Jeep at
>>> http://members.cox.net/jerrypb/
>>
>>
>
> --
> Jerry Bransford
> PP-ASEL N6TAY
> See the Geezer Jeep at
> http://members.cox.net/jerrypb/

"Nathan Otis" > wrote in message
...
> Thanks Jerry... I'll probably drop the angle just a little more this
> weekend. I did know the pinion needs to be pointed at the output, but it's
> tough to see exactly where everything is pointed...
> n.


Use a cheap straight line laser... works perfect for this job. You can
probably find one for under $10.

-Brian

Did you ever unhook the front driveshaft as was mentioned? Vibrations
can come from sneaky places.....

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Nathan Otis wrote:
>
> Ok, I got under the TJ and dropped the pinion a little (adjusting the UCAs
> accordingly). I still have vibration at 55+. This weekend I'll probably drop
> it a little more to see if that does the trick... I guess the option is put
> spacers on the t-case skid, but it doesn't seem like I should have to what
> with the CV shaft and all...
>
> Is there something I'm missing?
> n.

Mike,

It seems counter intuitive that the vibes would be coming from the front,
because 1. I haven't changed anything in the front and 2. I had to drive in
4hi with no rear shaft for a while and there were no vibes during that time
so 3. why would there be a problem in the front all of a sudden?

Still, if I can't get rid of it with control arm adjustments tomorrow
morning, I'll try pulling the front shaft for kicks. Thanks for the tip.
n.


"Mike Romain" > wrote in message
...
> Did you ever unhook the front driveshaft as was mentioned? Vibrations
> can come from sneaky places.....
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> Nathan Otis wrote:
>>
>> Ok, I got under the TJ and dropped the pinion a little (adjusting the
>> UCAs
>> accordingly). I still have vibration at 55+. This weekend I'll probably
>> drop
>> it a little more to see if that does the trick... I guess the option is
>> put
>> spacers on the t-case skid, but it doesn't seem like I should have to
>> what
>> with the CV shaft and all...
>>
>> Is there something I'm missing?
>> n.

Nathan Otis wrote:
> Well.... That sounds _pretty_ percise ;-)
>

You don't want to have any one universal joint not making enough bend-
you'll get vibration (from the shaft going into an orbit) and short
u-joint life (if the joint isn't bending far enough then the grease
isn't able to do its job, it gets squeezed between all the needles and
the needles beat dents into the cap and trunion.

IIRC, Spicer recommends a minimum 7 deg. angle to ensure grease
distribution.

Also, if you drove this for some time with the rear shaft out, check
that bearing in the transfer case- the output shaft might have been
hammering the bearing due to the lack of load.

I take it you've got a new rear shaft there, are the yokes aligned?

John