Pinion angle... what's the secret?
 

I thought I had my pinion angle adjusted pretty well Sunday when I attached
the driveshaft, but I have a vibration that starts at about 40mph, dies off
at around 50 and picks up again at about 60.

My helper and I held a carpenters square (the big L shaped one) on the diff
and lined it up that way, pointing directly at the output of the
transfercase... Can anyone give tips that will get me dead on?
n.

Is there plenty of room for the slip joint to travel, and you do
have the constant velocity joint, right?
http://www.4xshaft.com/driveline101.html And
God Bless America, ßill O|||||||O
http://www.billhughes.com/

Nathan Otis wrote:
>
> I thought I had my pinion angle adjusted pretty well Sunday when I attached
> the driveshaft, but I have a vibration that starts at about 40mph, dies off
> at around 50 and picks up again at about 60.
>
> My helper and I held a carpenters square (the big L shaped one) on the diff
> and lined it up that way, pointing directly at the output of the
> transfercase... Can anyone give tips that will get me dead on?
> n.

bad!
the output shaft of the transfer case and the output from the rear
differential should be parallel within 5 degrees or you will get a
vibration.
this is not true if you have a double u joint(cv joint)
then what you have done applies.
old john


"Nathan Otis" > wrote in message
...
> I thought I had my pinion angle adjusted pretty well Sunday when I
attached
> the driveshaft, but I have a vibration that starts at about 40mph, dies
off
> at around 50 and picks up again at about 60.
>
> My helper and I held a carpenters square (the big L shaped one) on the
diff
> and lined it up that way, pointing directly at the output of the
> transfercase... Can anyone give tips that will get me dead on?
> n.
>
>

IT depends on the kind of driveshaft you're running, a CV
(double-cardin) or a conventional driveshaft. The pinion should point
directly at the output of the t-case only if the driveshaft is a CV. If
it's a conventional driveshaft, the pinion angle must be parallel to the
output shaft.

Nathan Otis wrote:
> I thought I had my pinion angle adjusted pretty well Sunday when I attached
> the driveshaft, but I have a vibration that starts at about 40mph, dies off
> at around 50 and picks up again at about 60.
>
> My helper and I held a carpenters square (the big L shaped one) on the diff
> and lined it up that way, pointing directly at the output of the
> transfercase... Can anyone give tips that will get me dead on?
> n.
>
>

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

Plenty of room for travel. CV joint, correct.
n.

"L.W. ("ßill") Hughes III" > wrote in message
...
> Is there plenty of room for the slip joint to travel, and you do
> have the constant velocity joint, right?
> http://www.4xshaft.com/driveline101.html And
> God Bless America, ßill O|||||||O
> http://www.billhughes.com/
>
> Nathan Otis wrote:
>>
>> I thought I had my pinion angle adjusted pretty well Sunday when I
>> attached
>> the driveshaft, but I have a vibration that starts at about 40mph, dies
>> off
>> at around 50 and picks up again at about 60.
>>
>> My helper and I held a carpenters square (the big L shaped one) on the
>> diff
>> and lined it up that way, pointing directly at the output of the
>> transfercase... Can anyone give tips that will get me dead on?
>> n.

I do have the CV.
n.

> wrote in message
...
> bad!
> the output shaft of the transfer case and the output from the rear
> differential should be parallel within 5 degrees or you will get a
> vibration.
> this is not true if you have a double u joint(cv joint)
> then what you have done applies.
> old john
>
>
> "Nathan Otis" > wrote in message
> ...
>> I thought I had my pinion angle adjusted pretty well Sunday when I
> attached
>> the driveshaft, but I have a vibration that starts at about 40mph, dies
> off
>> at around 50 and picks up again at about 60.
>>
>> My helper and I held a carpenters square (the big L shaped one) on the
> diff
>> and lined it up that way, pointing directly at the output of the
>> transfercase... Can anyone give tips that will get me dead on?
>> n.
>>
>>
>
>

Sorry guys, I guess I figured folks had been following my posts closer than
this... I've been posting questions about this modification for two weeks
now...

Here's the specs:

2003 TJ (Rubi, if it matters)
3+" Suspension lift, 1.25" Body lift, transfer case skid probably lifts
things another 1.5 - 2 inches. Adjustable rear upper control arms are
pointing the pinion pretty much directly at the output of the T-case, and I
do have a CV shaft on this Jeep.

The shop that made the shaft claims all their shafts are precision balanced,
but I see no weights on the outside of the shaft. Another Jeeper running the
same shaft also has no weights, but has no vibrations. If anyone can help me
iron out these vibes, I'd appreciate it.
n.

"Jerry Bransford" > wrote in message
news:9cbXd.70110$Tt.14056@fed1read05...
> IT depends on the kind of driveshaft you're running, a CV (double-cardin)
> or a conventional driveshaft. The pinion should point directly at the
> output of the t-case only if the driveshaft is a CV. If it's a
> conventional driveshaft, the pinion angle must be parallel to the output
> shaft.
>
> Nathan Otis wrote:
>> I thought I had my pinion angle adjusted pretty well Sunday when I
>> attached the driveshaft, but I have a vibration that starts at about
>> 40mph, dies off at around 50 and picks up again at about 60.
>>
>> My helper and I held a carpenters square (the big L shaped one) on the
>> diff and lined it up that way, pointing directly at the output of the
>> transfercase... Can anyone give tips that will get me dead on?
>> n.
>
> --
> Jerry Bransford
> PP-ASEL N6TAY
> See the Geezer Jeep at
> http://members.cox.net/jerrypb/

"Nathan Otis" > wrote in message
...
> Sorry guys, I guess I figured folks had been following my posts closer
> than this... I've been posting questions about this modification for two
> weeks now...

Remove your front driveshaft and go for a ride. If the vibes disappear, you
have to look at your front pinion angle/castor. Do you have adjustable front
control arms on this monster? I'd be willing to bet the vibes are in the
front if you have done everything right in the rear.

-Brian

Well then, it sounds like your transfer's about to explode:
http://www.billhughes.com/BrokenCase01.jpg ;-)
God Bless America, ßill O|||||||O


Nathan Otis wrote:
>
> Plenty of room for travel. CV joint, correct.
> n.

When we put a ford 9" in daughter's jeep and a double cardon shaft we were
told from drive shaft place that pinion should be pointing 2 degrees below
transfer, it's been in for a year, no vibration.

"Nathan Otis" > wrote in message
...
>I thought I had my pinion angle adjusted pretty well Sunday when I attached
>the driveshaft, but I have a vibration that starts at about 40mph, dies off
>at around 50 and picks up again at about 60.
>
> My helper and I held a carpenters square (the big L shaped one) on the
> diff and lined it up that way, pointing directly at the output of the
> transfercase... Can anyone give tips that will get me dead on?
> n.
>