in this video we're gonna go over some
of the symptoms that you might find if
you have a bad or defective rear
driveshaft carrier bearing hey friends
it's Bolin here from 1a auto today we
made our way underneath of a pickup
truck because we wanted to talk to you
about a rear driveshaft carrier bearing
okay so if we're starting at the
transfer case which is pretty much in
the center of the vehicle as you make
your way back you're gonna see this
shaft going right back to the rear
differential this long shaft is called
the rear driveshaft a lot of times these
drive shafts will have two u joints
other times they'll have three or even
more if you have more than two you're
gonna need to have a carrier bearing the
carrier bearing would be located
somewhere in the center of the
driveshaft or at least close to Center
and it would look something like this
this is a really poor example because
it's in very poor condition if you were
to come along this side you can see
approximately where a lot of the rubber
is actually coming right out of there
and it's pulling out this can be very
dangerous
some of the things that you might notice
when you're driving in a vehicle that
has a carrier bearing that looks like
this is vibration under acceleration
maybe you're going up a hill you step on
the gas it's gonna put a lot of torque
on this rear drivetrain and it's gonna
be able to shake around you might also
notice noise maybe you're hearing this
just spinning around inside the area
where it's at or even a grinding noise
if the bearings that are inside there
are no good as well so just a quick
explanation of what a carrier bearing
actually does if you have a vehicle such
as a pickup truck with an extended
wheelbase or it's a very long pickup
truck you're gonna need to have one of
these carrier bearings the reason for
the carrier bearing is because the
driveshaft is gonna have to go from
either the transmission or transfer case
and it's gonna have to go a very long
way to get to the rear differential if
you have a very long long straight
driveshaft more than likely you're gonna
have a balance issue they kind of needed
to make it so there's a support in the
center and then they'll have another
joint that way there with this being
supported there's less issues where
you're going to get flex or vibration
from that drivetrain under acceleration
or under torque this right in the center
here has to have a bearing and it has to
move freely
let's just talk about a couple quick
causes of why something like this might
happen
well if you have a bad you joint which
this is considered you joint right here
and there's also another one down at the
far end next to the pumpkin of the
differential and more than likely one up
towards the transfer case in this case
if it's a bad you joint and it's binding
inside maybe it doesn't have anymore
lubrication in there and it's heating up
and it starts to bind it can cause a lot
of shake and as this would shake around
its gonna put premature wear on the
rubber or long hair you could also just
have an issue where well rubber breaks
down over time
maybe things get a little rusty and they
start cutting into it but basically the
main reason why something like this
might go bad over time is more than
likely due to an underlying condition
like I said maybe a bad u joint down the
line so you definitely don't want to say
I only need a center carrier bearing
without actually checking all of your u
joints first obviously our center
carrier bearing is an extreme case
situation here having the rubber bushing
pulling out like that is very extreme it
means it's pretty much completely torn
away from the outer portion where it's
supposed to be connected on to yours
might not look like this
yours might be less apparent you might
only see little baby cracks kind of
going in between where you think it's
supposed to be connected but there might
be a real problem that you just can't
see yet to inspect that you don't
necessarily need to drop the whole rear
driveshaft you can go ahead right up
here and you can take out the nuts
there's gonna be one there one there
slowly bring this down and then you can
take this and kind of move it around
it's supposed to kind of wiggle around a
little bit because it is only rubber
it's supposed to be a rubber mounted so
it'll have a little bit of movement
should it go like this no should go like
this a little bit yeah that's probably
fine inspect it check for cracks any
type of damage if yours looks like this
you don't even really need to do that
the next thing I would do is pretty much
just take down the whole rear driveshaft
and now expect all the u joints going
down the line so we've got the
driveshaft down on the ground because
it's a little bit easier to diagnose and
take a peek at these things without
having anything connected to the vehicle
I can move anything around how I want
as you can tell the bearings have noise
what I have heard that up in the air
probably not if I was to grab on to this
I could also try to move it around it
should not move around like this this
should be all connected inside there and
if I was to try to wiggle it it should
be able to do this a teeny bit but to do
this with just my bare hands
that's really bad if this was to
separate what's to prevent your drive
shaft from just going out of control
while you're driving down the road now
obviously we don't want to stop with
just diagnosing the fact that this is no
good we need to see if there's any
potential causes of why this could
happen yeah it could be dry rotted it
might be a little cracked and this
separation could happen over time it's
quite possible but there might be other
issues maybe the drive line itself could
have a binding issue and something such
as maybe a u-joint of some sort and it's
also putting extra stress on the rubber
bushing here so what you would need to
do while your drive shaft is out just
kind of grab onto here and move this
around up and down feels nice and free
if I try to go side to side I can almost
feel like it wants to bind in one area
and then I go the other direction and
then it's loose and then tight and then
this side right here loose so if you
have a u-joint which is this unit right
here that's binding in either direction
up down left or right or even just kind
of trying to spin it around that could
potentially cause an issue that's going
to be detrimental to your carrier
bearing if you're doing one you joint
obviously you want to take a close look
at all the rest if they look as though
they're rusted or maybe the grease or
anything might be missing from behind
the caps you'd want to replace those as
well the drive shafts already out for
this one right here if you wanted to you
could carefully grab this pull it out
and you can take a peek on the inside
you see all those little roller bearings
in there they need to be well lubricated
if you pull this off and it looks like
it's just dusty and red and full of rust
that means there's no grease in there
and it's overheating
and it's gonna potentially cause a major
issue definitely replace your u joints
if that's the case okay friends so we
try to make a quick video for you on
certain things that you can look for to
diagnose a rear carrier bearing issue
hopefully you learned a little something
along the way if you did and you want to
talk about it leave it in the comment
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