Notes

is how it changes when you lift the

vehicle

and also some terminology as well

because there's a lot of confusing terms

here

one of the first things we're going to

talk about is terminology and
0:16
and what all the different names mean so
0:19
a lot of times you'll hear the word
0:20
double carton
0:21
a lot of times people call it a double
0:22
cardigan it's not a double cardigan
0:25
cardigan's a sweater
0:29
in this case we're talking a card in and
Double Carton
0:31
so i'm going to just draw it here
0:33
write it out so it's it's cardin
0:36
c-a-r-d-a-n
0:38
and you can think of it as two-words car
0:40
and guys named dan so kardan
0:42
so what a double carton is double carton
0:45
is really just short for double u joint
0:47
so this is what you'd call a carding
0:49
joint
0:50
more commonly it's called a universal
0:51
joint i'm talking about
0:54
is one end of the drive shaft
0:56
specifically so this has two universal
0:58
joints
0:58
so we'd call it a double carton a lot of
CV
1:01
times we'll call this a cv as well
1:03
around the shop we say cv more than we
1:05
say double carton because it's just
1:07
easier to say
1:08
what cv stands for is constant velocity
1:11
and while this
1:12
is pretty close to a constant velocity
1:15
joint
1:16
it's not a true cv a cv
1:19
is what you see here so this is like a
1:22
drive shaft out of a jk
1:23
a lot of jeeps run these nowadays a lot
1:25
of other vehicles but this is a cv joint
1:28
so this is a constant velocity joint uh
1:31
the distinction here is we would call
1:32
this a
1:33
rosa cv so a lot of people wonder why do
1:35
you need a double garden
1:37
common misconception is people think
1:38
that this because there's two joints
1:40
it's going to flex twice as far
1:42
as let's say this end you think if this
1:44
end flexes to
1:45
20 degrees then this because there's two
1:48
of them it's going to flex to 40 degrees
1:50
that's not the case normally this joint
1:52
even though there's two of them it's
1:54
going to flex only about as far as this
1:55
joint before it binds up before it stops
1:57
what this does is it transmits power
2:00
more smoothly through steeper angles
2:01
which we'll get into
2:03
a lot more in depth here in a minute all
2:04
right so universal joint
2:06
because it only pivots in two directions
2:08
like this it's a lot like
2:10
a universal joint on a ratchet driver so
2:12
if you've ever used one of these which i
2:13
think most of us have
2:14
it runs real real smooth if it's running
2:16
straight but if you're really trying to
2:18
go around a tight corner
2:19
it's going to want to speed up and slow
2:21
down it runs real rough
2:23
so same thing with the drive shaft if
2:24
it's running straight it runs real
2:26
smooth
2:27
but if you have a lot of angle on there
2:28
it's going to run real rough here we
Jeep CJ
2:30
have a drive shaft that you'd find in a
2:31
lot of stock
2:32
vehicles this particular length it might
2:35
be in a jeep cj
2:37
has a single u-joint at each end and
2:39
this works in stock vehicles because
2:40
it's real flat
2:42
for this type of shaft to work well you
2:44
need to have two things happen
2:46
one is that these two joints are running
2:48
parallel to one another which in this
2:49
demonstration this transfer case tips
2:51
down slightly
2:52
the pinion slips tips up slightly so
2:54
they're parallel to
2:55
one another but the big one and this is
2:57
the one that you can't achieve on lifted
2:59
vehicles
3:00
is that the joint angle here is less
3:02
than about 10 degrees
3:04
so the joint angle is not the angle of
Joint Angle
3:06
the drive shaft a lot of people just put
3:08
angle finder on the drive shaft they say
3:10
that's
3:11
20 degrees i have a 20 degree drive
3:13
shaft angle
3:14
what's really important is is what is
3:16
the relationship between this
3:18
and this so in this case this is
3:19
actually ten degrees this is about three
3:21
this is about three so the operating
3:24
angle of this joint is
3:26
three minus ten seven down here same
3:29
thing seven degree joint angle
3:31
so two joints running at less than 10
3:32
degrees each they're parallel
3:35
that oscillation that you get out of
3:36
this u-joint gets cancelled out by this
3:38
u-joint
3:39
and so it runs smoothly up to a point
3:42
once you exceed about 10 degrees 10 is
3:44
not a hard line but about 10 degrees
3:46
certainly up
3:47
into 15 degrees these joints are just
3:49
oscillating too much
3:50
and they're fighting each other and
3:52
they're not going to cancel each other
3:53
out
3:54
so that's where we come to the double
3:55
garden now to show what happens when you
3:58
lift a vehicle to simulate
4:00
that what we have here is this pinion is
4:02
just sitting on some
4:04
eight inch sections of tube we're going
4:06
to take these out
4:07
put it on some five inch sections of
4:08
tube so that's going to in effect
4:10
simulate what happens when you install a
4:13
three inch lift
4:14
okay so now that we've lowered this
Drive Shaft Angle
4:15
pinion three inches in effect
4:17
uh installing a three inch lift on this
4:19
vehicle i've measured this again
4:21
now this angle the angle of the drive
4:22
shaft the slope of the drive shaft it's
4:24
about 20 degrees
4:26
before it was 10 so the relationship
4:28
between the drive shaft and the transfer
4:29
case or the pinion was about seven
4:31
now it's about 17 at each end so if you
4:34
remember 10 is kind of the limit
4:36
um we're at 17 that's well beyond the
4:38
limit so this is going to run rough
4:40
these u-joints are just running too much
4:42
they're oscillating too much they're
4:43
fighting against each other
4:45
and they're not going to be able to
4:46
smooth each other out one thing that a
4:48
lot of people
4:49
misunderstand is they think the only
4:51
thing that matters is is this parallel
4:53
in this parallel
4:54
and they'll just measure that and say my
4:55
pinion's parallel to the trans case
4:57
therefore this is the type of shaft i
4:59
need and that's a little bit backwards
5:00
the way you really
5:02
determine what type of shaft you need is
5:03
you measure the angle of the transfer
5:05
case which you can do
5:06
just measure off the yoke if the if the
5:08
drive driveshaft's removed we have a
5:10
video showing how to measure angles and
5:12
all that we have some info on our
5:13
website but you measure
5:14
angle the transfer case measure the
5:16
angle of the drive shaft
5:18
and if the difference between those two
5:19
numbers is greater than 10 degrees
5:22
especially by a lot this isn't going to
5:24
work doesn't matter if these are
5:25
parallel or not
5:26
now you do the double carton and the
5:29
pinion adjustment the rules change
5:31
before these need to be parallel
5:33
but now you need to rotate the pinion to
5:35
match the drive shaft
5:36
one thing to point out too is in this
5:38
case this would be for a rear drive
5:39
shaft the trans case points down toward
5:42
the the drive shaft and so that
5:43
decreases the angle if it was on the
5:45
other side of the transit case so a
5:47
front drive shaft
5:48
that transit case is going to point up
5:49
away from the drive shaft
5:51
so that's going to compound that angle
5:53
and on most
5:54
vehicles the front drive shaft the
5:56
geometry is just wrong
5:58
it always was if it doesn't have a
5:59
double card and it should
6:01
a lot of part-time four-wheel drive
6:02
vehicles they'll put this type of shaft
6:04
in the front because it's utilitarian
6:06
it's cheap it's easy it turns the wheels
6:08
when you need to you unlock the hubs
6:10
who cares if it runs smooth the rear
6:12
shaft is where we really want to focus
6:13
our efforts on getting things smooth
6:15
because if you're in two wheel drive
6:17
you're going down highway the shaft is
6:18
spinning this is the one that's
6:20
that's getting you from from home to
6:21
work and this is the one that you really
6:22
want to run smoothly
6:24
if your front shaft is running all the
6:25
time you probably need to look at that
6:27
too
6:28
the pinion angle adjustment rules change
6:30
you don't really want to adjust that
6:32
on the front you can't really get the
6:34
angles perfect um
6:35
because they're steering caster but you
6:38
can still get it
6:39
uh the least bad option so a lot of
6:41
times that will still be the double
6:42
carton
6:43
all right so now we have the double
6:44
carton style drive shaft installed
6:46
and in up here where before we had a
6:48
single u-joint running at 17 degrees
6:51
we really now have one two u-joints
6:54
running at
6:55
eight and a half degrees each down here
6:57
though this one is still running at 17
6:58
degrees
6:59
these two you could kind of think of it
Drive Shaft
7:01
as the drive shaft we had before
7:03
of 2u joints running at equal angles
7:05
less than 10 degrees
7:06
so you know one two less than seven uh
7:09
seven degrees less than ten each
7:10
but now this one is the odd man out and
7:13
this one
7:14
is not working in sync with these so
7:16
what we need to do with this drive shaft
7:18
is uh rotate this pinning up so that
7:21
we're decreasing this joint angle to
7:23
almost nothing
7:24
okay so now that this pinion is up what
7:26
i'm really shooting for here is i want
7:28
this pinion to be about
7:29
two degrees two or three degrees less
7:31
than the angle of the drive shaft so
7:33
if the angle the drive shaft is 20 you
7:35
want this to be
7:36
around 17 18 degrees there's a couple
7:39
reasons for that one
7:40
is on leaf spring type vehicles there's
7:41
axle wrap so
7:43
as you're moving forward your wheels are
7:45
trying to turn one way
7:46
your opinion is trying to rotate the
7:48
other way and those leaf springs are
7:49
going to flex
7:50
so if you start with the pinion and it's
7:51
a little bit low under load
7:53
you're going to go from let's say two to
7:55
one to zero to one to two and you stay
7:58
within that two or three degree range
8:00
pretty much the whole time
8:01
if you start with zero or even too high
8:04
you're going to go from zero to one to
8:07
two to four
8:08
and then you have too much joint angle
8:09
momentarily but you're gonna get shudder
8:11
out of that drive
8:12
shaft on a coil spring type vehicle with
8:15
control arms
8:16
that doesn't really move but you still
8:18
you can put a degree
8:19
two degrees here you don't necessarily
8:21
want to have zero and that's because
8:22
these u-joints they need to be able to
8:24
behave
8:25
as bearings a little bit they need to be
8:26
able to move a little bit so as long as
8:28
this is minimal
Measuring Pinion
8:30
it's good the way to do it is you
8:32
measure the drive shaft
8:34
you measure the pinion and you want the
8:36
pinion to be about two degrees less
8:38
you don't care what this is anymore it
8:39
doesn't affect the pinion angle
8:41
adjustment
8:41
one benefit that you get as you bring
8:43
this pinning up
8:44
we'll grab a drive shaft is
8:48
it's drive shafts here and if you're
8:49
lifting up the pinion you're lifting up
8:51
the bottom end of the drive shaft so
8:52
you're decreasing the angle on the drive
8:54
shaft
8:55
which helps to decrease the angle up
8:57
here and that just gives you greater
8:59
wear life these things are not moving as
9:01
much as they were before
9:02
so now that this is effectively zero
9:04
we'll call this zero it's two degrees
9:06
but for all intents and purposes this is
9:07
not running at any angle
9:10
so what we have now uh with this double
9:12
carton is a lot like the same operation
9:14
of this shaft if you could imagine this
9:16
shaft just squeezed together to where
9:18
these two joints are right here
9:20
you have the same thing two joints
9:22
running at less than 10 degrees they're
9:24
running in unison they're cancelling
9:26
each other out
9:27
this joint's not doing anything so this
9:28
runs smoothly in a lot of short
9:30
wheelbase vehicles
9:31
big benefit here is that because you're
9:34
bringing this pinion up you're reducing
9:35
the
9:36
angles and where maybe before you had
9:38
something that just won't work
9:40
you're really helping to reduce the
9:41
angles on the drive shaft and you get
9:42
back into the realm of
9:44
something that will work but the main
9:46
benefit is that it runs smoothly
9:48
you don't get those those low speed
Vibrations
9:50
shutters one thing that i should point
9:52
out is that
9:53
the vibrations that you get from this
9:55
it's not a high speed vibration
9:57
necessarily
9:58
if you have a vibration at 60 miles an
10:00
hour it's most likely that your
10:02
driveshaft is not balanced
10:03
or that it's loose if this part of the
10:05
shaft is worn out and this is rattling
10:06
around
10:07
and it's spinning real fast it's going
10:08
to vibrate at high speed the type of
10:10
vibration you're going to get from this
10:12
type of shaft running at too much angle
10:15
is a throttle related vibration
10:17
typically
10:18
so what that means is on acceleration
10:21
on heavy load going uphill it's going to
10:24
be at its worst
10:25
when you let off the gas and the drive
10:26
shaft vibration goes away
10:28
that indicates that it's an angle
10:29
related issue if um
10:32
if it's something that you only get from
10:35
takeoff
10:35
up to maybe 40 miles an hour that's
10:38
something that it's almost
10:39
always an angle related issue one thing
Slip Yoke
10:41
that i didn't
10:42
cover that i need to point out is if you
10:45
have if you start with this type of
10:46
drive shaft
10:47
you have a yoke on the transfer case and
10:49
you just get this
10:50
this double carton shaft and you go to
10:52
bolt it up it's not going to quite
10:54
fit the u-joint will fit the yoke but
10:56
you'll go to put the
10:58
bolt holes in and you'll find that
10:59
they'll they don't line up if you're
11:01
using the u-bolt style yoke
11:03
so if you have a transfer case that
11:05
already has a fixed yoke like this one
11:07
you need to get a double card and
11:09
compatible yoke on our website i think
11:11
we list them as cb
11:12
yolks because the words are used kind of
11:14
interchangeably but you need to change
11:16
the yolk on the transfer case
11:17
if you don't have a fixed yoke so if
11:19
this is if you have an
11:20
xj a lot of grand cherokees a tj
11:24
a yj a lot of different jeeps came with
11:27
a slip yoke
11:28
and so that driveshaft there's an output
11:31
shaft
11:32
what we'll call this the output shaft
11:34
and then the drive shaft slides onto
11:35
that output shaft
11:37
uh there's no good way to bolt up a
11:39
double card and shaft to that vehicle so
11:41
for
11:42
slip yoke style transfer cases you need
11:44
to do
11:45
a slip yokolovnida kit so that's what
11:46
this has right here
11:48
it's converted to a fixed yoke
11:50
specifically a double carbon compatible
11:52
yolk and that's really the reason to do
11:54
the slippy oakland noodle kit
11:55
we're going to have a video covering
11:56
those as well so if you want to dive
11:58
deep into the slippy oak limited kit
Pinion Bearing
12:00
look for that video sometimes when we
12:02
tell people they need to adjust their
12:03
opinion
12:04
they're concerned that their pinion
12:07
bearing is not going to get enough oil
12:09
and that's because you're when you bring
12:10
this pinion bearing up
12:12
you're bringing it away from the oil
12:13
bath in the differential
12:16
but it doesn't really matter the pinion
12:17
still gets the oil and i'll explain why
12:19
when you have this this is a cross
12:21
section so you can see what's in here
12:23
and there's oil in here and i don't know
12:25
what the level is it might be right
12:26
about here
12:27
might be higher actually actually here's
12:29
the fill plug so yeah here's where the
12:30
oil level is
12:32
and even if that was flat the pinion
12:33
bearing wouldn't necessarily be
12:35
submerged in it
12:36
but the way the oil really gets cycled
12:38
through here
12:40
to all the parts is by the ring gear
12:43
so this is the pinion gear um that's
12:46
driven through the drive shaft and then
12:48
that
12:48
in turn drives this ring gear and this
12:51
ring gear
12:52
is spinning at about the same rpm as
12:54
your tires
12:55
and as that's spinning these gears
12:58
they're picking oil
12:59
and much like a tire in mud they're just
13:02
slinging oil all over the place
13:04
so this is spinning it's slinging oil up
13:07
here
13:08
there's a little channel here it's not
13:10
real big you wouldn't think the oil
13:11
could get through there but
13:12
it's splashing up in there and it's
13:14
getting to that bearing a lot of people
13:15
will say that they ran their opinion
13:17
at you know whatever how many degrees 20
13:20
degrees and the opinion bearing burned
13:22
up
13:22
and they think cause and effect but what
13:25
really is happening with that pinion
13:27
bearing is
13:28
that pinion bearing is spinning faster
13:31
than the other bearings in the
13:32
differential
13:33
the reason for that is the gear ratio so
13:36
this is let's say it's a 410 gear ratio
13:39
what that means is every four rotations
13:42
of the drive shaft
13:43
every four rotations of the pinion shaft
13:46
is
13:46
one rotation of that ring gear so this
13:49
is spinning four times faster
13:52
four times as many times so you know
13:54
every
13:55
100 rotations here is 410
13:58
here and so this bearing
14:02
is going to wear out four times as fast
14:03
it's just you know plain math
14:05
so if that wears out first it's not
14:06
because it's not getting oil it's just
14:08
because it's spinning faster
14:09
but when you rotate that pinion you're
14:11
changing the location of that fill plug
14:13
so in this case we're lowering the fill
14:15
plug
14:16
and then if you use that fill plug as an
14:17
indicator of how much oil to put in
14:19
you're not putting in enough oil it's
14:21
really important to have enough oil but
14:23
as long as you have the right amount of
14:24
oil
14:24
it's going to get where it needs to be
14:26
it's going to do its job sometimes
14:28
people
14:28
ask us instead of adjusting my opinion
14:30
to get this shaft to run smoothly
14:32
why can't i just run this double card
14:34
joint at both ends
14:35
and then it shouldn't matter what the
14:36
pinion is and that's valid i see where
14:39
they're coming from with that
14:40
but the reason we don't do that on on a
14:42
rear shaft specifically
14:44
is mostly because it's unnecessary but
14:47
it also has some disadvantages
14:49
so the disadvantage is there's more
14:51
parts here there's more stuff in this
14:53
end of the drive shaft and it's heavier
14:54
at this end of the drive shaft
14:55
we add this to this end of the drive
14:57
shaft drive shaft overall
14:59
is now heavier and when you're going
15:01
down the road at 60 miles an hour
15:03
most vehicles their drive shaft is
15:05
spinning about 2500 rpm
15:08
the more weight you have spinning at
15:10
those high rpm the more likelihood you
15:12
have for high speed vibration
15:15
also when you're adding these parts to
15:16
this end of the drive shaft you're
15:18
adding
15:18
more moving parts and the more moving
15:21
parts you have especially
15:22
at this lower end of the shaft is closer
15:24
to the ground and dirt and water
15:26
the more things that might wear out and
15:28
might fail on you
15:30
also the drive shaft with with double
15:31
cardinality change is more expensive
15:33
unnecessarily so in any rear application
15:37
where we do build a shaft with a double
15:39
card in each end
15:40
is on front shafts on full-time
15:43
four-wheel drive vehicles where the
15:44
front shaft is spinning all the time
15:46
so think uh grand cherokees and
15:49
grand cherokee was a lot of lift where
15:51
the pinion
15:52
and the drive shaft there at odds with
15:54
one another and you can't adjust the
15:56
pinion because the steering caster is
15:58
is involved so if you adjust the pinion
16:00
to benefit the drive shaft
16:02
you're going to mess up the steering
16:03
caster your drive shaft's going to run
16:05
smoothly but the jeep's going to wander
16:07
it's not going to handle well so in
16:08
those instances
16:10
where the normal double carton shaft
16:12
just doesn't run smoothly
16:13
we're going to do the double card into
16:15
each end and it's not necessarily a
16:17
good option it's the best option for bad
Recap
16:20
circumstances
16:22
to recap when we say double carton when
16:24
we talk about a double carton style
16:26
driveshaft
16:26
we're really saying a double universal
16:29
joint
16:30
and specifically at this end of the
16:31
drive shaft so the double carton is at
16:33
the trans-case end of the drive shaft
16:35
because that's where we can't really
16:36
adjust the angle on a lifted vehicle
16:38
and that's where we have to split it
16:40
between two joints a
16:42
double garden shaft does not necessarily
16:44
flex further
16:45
than this type of shaft a single joint
16:47
before it binds up
16:48
before it just stops sometimes it does
16:50
oftentimes it doesn't
16:52
but what it does do is it transmits
16:54
power more smoothly
16:55
through those increased continuous
16:58
operating angles so just going down the
16:59
road
17:00
just normal ride height when you're
17:02
running the joint at 20 degrees
17:04
this is going to run a lot more smoothly