Hello, my name is John Kelly and this is the WeberAuto YouTube channel. Today we are going to
learn how to check the fluid level transmission fluid level on the ZF or ZF 8-speed automatic
transmissions that are used in Chrysler products BMWs other vehicles all use these 8-speed
automatic transmissions and these transmissions take a unique fluid I purchased this fluid today
from the local Chrysler dealer, this is the 8 and 9 speed automatic transmission fluid and it is kind
of hard to see and hold up a white paper behind it here but it's kind of a green tint kind of a
dark green tint automatic transmission fluid it is not your red ATF for that Chrysler transmissions
have used in the past this is a special automatic transmission fluid the price on this is around 43
dollars a quart so you want to be real careful with this fluid make sure you don't waste it but
what we have here today to check the transmission fluid level on is a 2013 Chrysler 300c with a 3.6
liter engine it has the 8HP45 transmission if you get a Chrysler I'm sorry a Dodge Ram pickup
truck with the 8 speed you'll probably have the 8HP70 and if you get the like a Hellcat it has
the 8HP90 and then other vehicle manufacturers use these same transmissions in rear-wheel drive
all-wheel-drive configurations seem to be a pretty neat transmission but it has a unique
transmission fluid level checking procedure that I want to take you through today and so if we look
at the bottom pan here of the transmission we have a drain plug right here and on the side of
the transmission pan right here in orange letters let me zoom in so you can see the orange sticker
with the yellow letters that sticker tells us that we need to use the proper fluid that I've already
shown you we need to check the transmission fluid level with this plug that is directly
above the sticker so the plug is right here we need to check the fluid level by removing that
plug when the transmission fluid temperature is read on a scan tool is between 86 degrees
Fahrenheit and 122 degrees Fahrenheit that's also 30 degrees Celsius to 50 degrees Celsius if you
check it when it's hotter than that the fluid will have expanded and you will definitely have fluid
come out of the plug and you will now drain that would have drain fluid out of the transmission
causing it to be under field so we have to check this fluid at the proper temperature there's a
three-page procedure right from Chrysler's dealer connect service information website for checking
the fluid level on this trans and so I want to go through this procedure and then show you an
additional thing that this procedure didn't tell you about that will definitely affect the fluid
level of the transmission that you need to be wary of so a fluid level checking procedure has
us raise the vehicle on a hoist to a level hoist so that the transmission fluid will be level with
the hoist itself now it tells us to start the engine, we're not going to start it yet before
we start the engine let me read a couple of more steps here if it's an all-wheel-drive vehicle we
have to remove the front prop shaft to access this plug but this is a rear-wheel-drive sled
doesn't apply we need to hook up a scan tool and verify that the transmission fluid temperature
is lower than 86 degrees Fahrenheit. alright so I've got a scan tool set up over here on this
cart behind me and if I zoom in here transmission oil temperature reads 79 degrees so 79 degrees we
are below 86 degrees if we start with the fluid temperature too high we will run out of
time as we go through the fluid level checking procedure that will cause the fluid to heat up
faster than we want it to and we will exceed the 122 degree Fahrenheit maximum and so
we want to start this fluid level check and procedure basically on a cold vehicle one that
has not been started yet so this is not something you're going to do during the lube oil and filter
it's got to be got to be a special procedure to do this okay so we're going to start the engine here
in a minute we're going to pull this plug out of the side of the transmission and if any fluid
comes out then we'll just catch that fluid in a drain pan if no fluid comes out then it tells us
to add fluid until it does come out so what this procedure what this step does is it adds enough
fluid to make sure that it's safe to even perform the rest of the fluid level check procedure
alright I'm going to loosen the plug first it takes a 8-millimeter allen wrench to loosen it
alright go ahead and start it up just let it idle
all right so I'm going to take that plug out all right I've removed the plug no fluid has
come out so that tells us that it's too low to even begin with and so I'm going
to add fluid so the procedure tells us to add fluid to the transmission until some
fluid comes out let me get positioned to do that I've put a flexible hose on
the top of the transmission fluid bottle and I'm going to add fluid here huh this
flute this transmission is definitely low I'm going to add some more, oh there we go
okay, so we've got fluid coming out as you can see it's dripping out of the side here
that tells us that we've got enough fluid in there now to continue with the fluid
level checking procedure so we put the plug back in alright the next step we've lowered
the vehicle now for the next step of the fluid level checking procedure it tells
us to disable the traction control then with the brakes applied put the transmission into
reverse and hold it for five seconds and then put it in Drive and hold it for five seconds
and then let off the brakes and slowly accelerate
to second gear and then hold it for five seconds in second gear
okay apply the brakes and put the transmission in neutral now raise
the engine speed to 2,000 rpm for five seconds
alright come back to Idol transmission in Park and now we got to put the vehicle back up on
the hoist pull that plug back out of the side and if there's if fluid drains out then it was
had too much fluid in it if no fluid comes out then we need to add fluid right now our
transmission fluid temperature is 90 90 degrees so we don't want to exceed 122 so we're at 90
okay we've got the vehicle back up on the hoist we kept the engine running we don't have a lot
of time our transmission fluid temperature is at 95 degrees and we have up until 122
this is kind of a cool day, if we would have started on a hotter day that would have given
us even less time so now let's take the plug out it tells us when we take it out if there's
any fluid that comes out that it was too full and just let it drain until it stops draining
okay so we're having fluid come out let it drain and not until it totally
stops but until it gets down to a slow drip drip drip kind of drizzle
flew temperatures up to 97
alright it looks like it's not gonna oh there we go okay we're down to just a slow
drip right there put the plug back in we'll come back and torque that spec here later
okay now supposedly we're done go ahead and shut it off so that is the official Chrysler service
information on checking the fluid level on these 8-speed transmissions but there's more a little
more to it than that and I learned about another issue that affects the fluid level on this at an
automatic transmission rebuilders Association conference last year in Las Vegas there was
a guy from ZF transmissions that that spoke about these automatic these eight speeds and
he was telling us that a lot of vehicles have a transmission cooler thermostatic bypass valve that
when the fluid level is cool enough to check this bypass valve is open and what that means is that
there's no fluid going through the transmission cooler at this low temperature and so I looked
up the thermostatic all right well I looked up the transmission cooler system on this vehicle which
is found under cooling rather than transmission and turns out the automatic transmission fluid
cooler is part of the air-conditioning condenser it's the top several rows of tubes across the
air-conditioning condenser so it's in front of the radiator which is actually pretty good it
gets cooler air than if it were in the radiator itself but in between that transmission cooler
and the transmission is this thermostatic bypass valve and I looked to see where it is located let
me show that to you okay so right here under the front suspension system we've got the
right and left tires here I've removed the engine undercover and right to the left-hand side of the
engine oil pan right up here is the thermostatic or temperature-sensitive cooler bypass valve
so that block of aluminum right here these two lines right here are coming from the transmission
they're just going to take a u-turn when the transmission fluid temperature is below 160
degrees Fahrenheit and then once it's above 160 it'll open up and allow fluid to go forward to the
transmission cooler up in the air-conditioning condenser so what does that mean for your
automatic transmission fluid level check that we just did that level check that we just performed
was done with this cooler bypass valve open so that fluid level is incorrect because there is
no fluid going through the cooler the cooler lines and there's these are some pretty good
diameter pipes and the condenser is pretty wide it looks to me like that would hold a lot
of fluid and there are several things to consider when we're talking about that cooler bypass valve
one of course is your fluid level if that whole system had drained when it was previously hot and
drained back into the transmission and now it's fairly empty when it finally does open at 160
degrees then your fluid level in the trans pan is going to be too low so that's another
thing to consider so that means that you're going to want to set the level with a cool then go drive
it get it nice and hot let this thing open up let this cooler a bypass valve open up and then let it
cool down again and then check the fluid level again just to make sure that you got all the
air out of the system especially if you've had the system open or if you've removed the transmission
you've overhauled it or whatever or replaced it you could have a lot of error in there that it's
going to affect your transmission fluid level also of course if you had a transmission failure and
you've changed the transmission and you haven't flushed the cooler by disconnecting the pipes
at the front of this thermostatic cooler bypass valve then you're still going to have all that
rotten fluid it up in in the transmission cooler that as soon as you put that new transmission in
warm it up to above 160 all that garbage is going to go back into your transmission on your cooling
passages your lubrication passages gears gears bearings and of course ruin everything so be aware
the guy from ZF said not every vehicle has this thermostatic bypass valve some of them it's built
into as part of the transmission cooler other manufacturers have it on the transmission itself
some manufacturers like Toyota have a method where you can push the valve to the closed position and
force fluid through the cooler and lock it in place with a pin but this one doesn't appear to
have any method of forcing it to let fluid through the cooler while you're checking the transmission
fluid level so this actually could be a two-day process by time you check it cold let it warm
up let it cool back down and check it again and I don't see a shortcut I don't see a way around that
so the fluid level checking procedure in the actual Chrysler service information tells you
nothing about this cooler bypass valve here and I'm positive that it makes enough it will have an
effect on the transmission fluid level so this has been a demonstration of checking the transmission
fluid level on the ZF or ZF 8 HP series automatic transmissions thank you for watching