[Music]
so right around 40 40 miles an hour
lightly accelerating I can hear and like
howling noise it's coming from the back
of the vehicle when I let off the gas
the noise goes away when I step on the
gas it comes back I can actually feather
the gas pedal and make the noise come
back and forth it's pretty bad what's up
guys I'm Andy from 1a auto in this video
I'm gonna give you some tips on how to
diagnose a rear differential do you need
any parts for your vehicle click the
link in the description and head over to
1a auto comm alright when you're
diagnosing the rear-end noise that you
have if it's noise that's constant all
the time what you can do is you can put
the vehicle up on the lift and have
someone driving be careful when you're
doing this you want to stay away from
this area because it's gonna spin real
fast with a driveshaft and the yoke and
stuff but you can take a stethoscope and
you can check right here in this area if
it's real loud in this area you're gonna
have a problem with your pinion bearing
it's really loud on the side over here
and over here on this side it's probably
your carrier bearings and then also if
you're only hearing it when you're
accelerating versus decelerating or vice
versa it's probably your ring and pinion
another thing you can check with is by
using chassis ears you can actually
attach chassis ears right here and right
here and over here what chassis ears are
are is basically little microphones that
are attached to wires some of them are
Wireless and then you can drive the
vehicle around and listen to where the
sounds are and see which sound is closer
to the actual noise you're looking for
another possibility is the bearings over
here those could be making noise it's
not as common to have these bearings go
bad but it does happen but generally
it's
the carrier bearings or the ring and
pinion pinion bearings I set up this
dial indicator to check the backlash
before I take this completely apart this
isn't normally what you would do but my
assumption with this rear-end is it was
set up wrong and that's why I'm getting
a noise so I just wanted a baseline it
before I take it all apart and see how
the backlash is what the backlash is is
basically to play between this gear and
the pinion gear it'll be a little slop
and they're supposed to be there's
supposed to be about eight to twelve
thousandths of backlash now what I do is
I'm going to hold the pinion with one
hand and then I'm gonna just rotate
rotate the ring the ring gear back and
forth and see how much backlash I have
and right there
I have almost 15,000 of a backlash which
is way too much now they have different
setups for a for a dial indicator you
can use they have some that have a
magnet that would be more ideal this
situation will work for us it's the best
I have available right now so I want to
check the pattern on this gear before I
take it out so I'm going to use some
gear marking compound and an acid brush
just mark this gear
we're gonna mark both sides so we just
want to what we're doing is we're gonna
try to see where the pinion is actually
riding on the ring gear because it needs
to be in a certain location otherwise
you're gonna get a noise or it's gonna
wear funny so I'm gonna take a pry bar
and I want to pry I'm here I'm just
gonna put a little tension on the ring
gear so that it smashes it pushes down a
little bit and spreads the gear marking
compound once it goes that way then I'm
going to put the pry bar on the bottom
and then you spin the pinion the other
direction as you can see on this side
that's where the pattern is pushing on
the ring gear from the pinion other side
looks like it's pushing right there so
when we were checking our pattern in
this ring and pinion when it was still
in the vehicle this one side which
happens to be the coast side the pattern
was actually pretty good it looked just
like this was right in the middle
it didn't look too deep didn't look too
far forward or too far back so but when
we were checking the drive side which is
when we were accelerating the pattern is
way down here and way here so there
wasn't a lot of contact touching the
ring gear which isn't good and that's
why we were getting a noise so it should
be like right there in the middle a nice
contact and we were getting it way on
the outer edges and a thin line contact
which is causing our noise and what we
found is it's probably due to lack of
changing the fluid and there was a seal
that was leaking and it was low so when
this was the opinion was riding up
against here it's actually worn down the
ring and pinion are worn so it's not a
good contact there
[Music]
we replaced the ring and pinion all the
bearings and put in the corrections okay
so we set this up again and put our
gauge on and we'll just check in the
backlash and we have about eight
thousands which is awesome that's
exactly where we want to be you don't
want to be too high you don't want to be
over 12,000 and you don't want to be
much under 7,000 so 8,000th is awesome
so we're gonna send it like that in case
you don't understand what I'm talking
about when I'm talking about backlash
and this measurement right here it's
what it is is the ring gear and the
pinion there's an air gap between the
two and if that air gap is too tight
then when all these components heat up
it's gonna bind up and cause a lot of
wear and then if the if the air gap is
too loose then you're gonna get clunking
while you're accelerating and
decelerating so that is why it's
important to have this adjustment
adjusted properly so we have the
backlash setup so we're good there so
now we want to check the pattern so I'm
gonna take some gear marking compound
and a small brush just mark this up I'm
gonna mark it up on both sides of the
ring gear and now we're gonna check the
pattern I'm gonna have a friend turn the
pinion while I use the pry bar and I'm
gonna put a little pressure on it and
what the pressure is doing is making it
so the patterns gonna spread a little
bit better otherwise if you do it just
do it
freewheeling then it's not going to
have as good of a pattern all right you
can stop now we're gonna go the other
direction
so now I'm gonna pry from the top all
right go ahead first we're gonna look at
this side now this area right here is
where the pinion was contacting the ring
gear now this is the drive side so when
you're accelerating going forward this
is where it is pushing on the ring gear
now ideally I would have rather it been
closer to the middle but that actually
looks pretty good where it is it's a
nice pattern
it's nice contact it's oval it's not
coming off the edge which it looks
really good and then if I looked at the
coast side is a nice oval on this side
as well and it's pretty close to where I
want it to be ideal would have been
closer to the middle but that looks
pretty good all right so we're done
we finished our repair we replace the
ring gear and we replace the bearings
while we were in there too and it's
probably kind of hard to hear on camera
but the rear differential is nice and
quiet so we actually fixed our problem
and we're good to go
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