Transmission Fluid Change, Part 1

My Freestyle's engine puts its power to the wheels via a CVT transmission.  CVT stands for "Continuously Variable Transmission" so the oft-said phrase " CVT transmission" is a bit like saying "RAM memory", or "you only YOLO once".

Thanks Mitsubishi motors

A CVT works by connecting two conical pulleys mounted on shafts, one being the power from the engine and there other being the output to the wheels, with a belt. The pulleys then change where the belt rides on the pulley to change the rotation speed of the input shaft compared to the output shaft. Or something like that.  Wikipedia contains an excellent description and history of this technology.



CVTs require more maintenance than fixed-gear transmissions, the unit in the Freestyle being notoriously finicky.  One key, required maintenance task is replacing the transmission fluid with Ford's special formulation harvested from unicorn gallbladders mixed with snipe tears, all for a modest $17 a quart.  I found some fluid from Valvoline at half the price that's supposed to be the same, so I'm going to go with that for my fluid change.  The back of the bottle says that this fluid interchanges with Ford's, so it must be alright.  At the same time, there's a filter that needs to be replaced, so I'll do that too.

Actually there's two filters in this unit.  A filter in the sump and "high pressure" filter in the case where the fluid heads over to the radiator.  The standard service calls for replacing the high pressure filter and fluid every 60K.  The "low" pressure unit does not have a service interval, so I'm going to leave it alone.

Here's the basic steps:

1. Warm-up the car
2. Open drain plug, catch fluid so it can be measured
3. Remove and replace filter
4. Refill
5. Re-assemble

Instead of one big post, I'll break this up into a few posts because things sort of went around the bend in step 3.  At 280k+ miles, unexpected stuff just breaks.

Warming-up the car

Torque (Lite) readout

Started-up the motor and waited -- easy enough.  I used the coolant temperature as a proxy for the transmission fluid temperature.  When it reached 100 deg C, I thought that was good enough, took about 15 minutes.  Temperature monitored Torque (Lite) app talking to a wireless OBD device.  When I took the screen shot, the temperature dropped two degrees, the radiator fan must have started spinning or it took me longer that I thought to press the screen save buttons.  Torque is a great application, it reads the standard set of things on an automotive CANBus, so you can get roughly the same data points for any car.

Draining the Fluid

Lifted the driver's side of the car, placed a jack stand.  The plug used a #6 hex tool, the hole was a filled with road crud, needed to tap the tool into place. Gave the wrench a twist, out came the fluid into a catch pan.  Note the green gasket; the kit for the new filter didn't include a new gasket for the plug.  The gasket looked to be in good condition, so I wasn't too worried.

Dirty fluid draining out

The fluid was warm, so heating the engine had the desired effect of also warming the transmission. As you can clearly see, the fluid looks well worn.   The camera just doesn't do justice to showing the grimy state of what was flowing out of the transmission.  Just like the brake fluid, the transmission fluid looks to be a long-term resident of the car.  While this was happening, I was keeping a nostril open for a burnt smell. Nothing of the sort. So far so good.  When it comes time to refill the transmission, I'll measure the fluid at room temperature and replace it with an equal amount of new fluid.

Accessing the Filter

From the top of the engine compartment, I removed the air intake and the filter box.  There's a retainer on the the transmission cooler lines held with a 8mm bolt.  That was a bit rusty, but loosened without much effort.

To access the rest of the parts, off came the tire and the inner fender lining.  The fender lining was held in place by those screws with plastic "expander" clips, almost like what you put in a wall to hang something heavy.  The screws didn't want to come out, so I pried and broke many of them in the process.  I figured I would just buy a pack from Amazon, maybe getting something a little easier to remove in case I ever need to do this again.

Supporting the transmission

Transmission mount on the car

Next step was removal of the transmission mount, held onto the sub-frame with two 15mm bolts and to the transmission with 13mm bolts.  But...  before removing the mount, I needed something to hold the engine/transmission in place, so I used my smaller (and from the picture, dirty) floor jack and some blocks of wood.  Once supported by the jack, I put a block of wood on a jack stand, placed it under the transmission in front of the jack and used that to support the weight.  With the load well supported, I went to work removing the mount.  The rust on the 15mm bolts made removal difficult, but they worked loose without too much trouble a little PB Blaster.  No surprises removing the 13mm bolts either.  The well supported transmission stayed put.

Transmission mount

I disassembled the mount and cleaned it with de-greaser and water.  There's lots of surface rust, but the part is otherwise in OK condition.  Before putting in back on the car, I'll use a wire brush to knock off the worst of the surface rust and use a "rust reformer" to prime and then some black paint to protect the part.   I'm not sure how much good this will do, hopefully it will extend the life of the part.

Stripped bolt

The bolts over the filter housing were so dirty, I needed to use a pick to remove the crud so I could get the T40 torx head into place.  I figured I would break the tension on the bolts, then remove the hoses.  This is where I found the lower-most bolt was stripped and wasn't moving. Stripped bolts aren't always a bad thing, it means that somebody did this service at least once before, maybe even several times.  Considering the mileage and 60k service interval, this was a little comforting.  Next post will pick-up the job from there, removing the bolt was a bit of a challenge.

Also, take note: there's lots of oily deposits.  Probably more than should be there.  There was a leak at the top of the engine I fixed by replacing the cam shaft seal, but what's there doesn't look like it's from the top of the engine -- another issue I wasn't expecting.   Fun times!