Tales From the Bench - June - 2016

A Look Inside Subaru CVT Generation 2 Part 2

In the April, 2016 issue of GEARS, we looked at Subaru Gen 2 and tore down the back half of the transmission, and removed valve body and the lower pan. In this issue we’re going to continue the teardown and make a tool necessary to get these transmissions rebuilt and back on the road.

REMOVING THE CASE

In part 1 of this article we prepped the case for removal. The valve body, linkage, and baffle bolts should already be removed.

Now you’re ready to remove the cooler lines, sensors, and case bolts.

Remove the case to access the pulley and clutch packs.

With the case removed, you can remove the baffle (figure 1).

This is where the fun begins: To remove the chain, you need to release pressure from it. To do that, you’ll have to compress the secondary pulley; then you can remove the chain and pulley system.

On the Subaru Gen 1 CVT, you could use a puller to open the pulley. On the Gen 2, you need to push the pulley forward to open it. That requires a special tool; you’ll have to build one, because they don’t appear to be available for purchase.

CHAIN REMOVAL TOOL

The Subaru Gen 2 requires a tool to remove the chain and pulley assembly. Subaru says the tool is discontinued and isn’t sold in the United States. I searched Google, eBay, Amazon, and many other places with no luck finding one.

As a transmission rebuilder, sometimes you have to make tools to get the job done. Some of the best tools are the ones you build yourself. This one is pretty basic and should be easy for you or a local machine shop.

Start with a piece of 3/16” thick steel plate, 14” x 11”. Drill two ½” in holes and cut out a large rounded slot (figure 2). The tool is going to slide into the side of the pulley so you can release the chain.

You’ll also need two pieces of 5/16” all-thread, about 12” long; four 5/16” nuts; and four flat washers.

REMOVING THE CHAIN

Take the tool you just built and slide it into the groove of the secondary pulley.

Attach the all-thread to the front case bolt holes (figure 3).

Tighten the nuts on the all-thread evenly on both sides. This will pull the pulley sheave forward and release the tension on the chain. Continue tightening the nuts until the chain becomes loose.

Start on the left side of transmission and pull the chain outward to remove the chain guide (figure 4).

To remove the guides, release the four locking tabs and separate them in the middle. Then remove the chain guide anchor; it’s attached with a 12mm headed bolt.

While you’re on this side of the transmission, remove the primary pulley retainer bolt.

Go to the right side of transmission and remove the chain guide anchor bolt; it has a 12mm head. Remove the bolts that retain the primary pulley.

Pull up on the primary pulley and tip it toward the secondary pulley (figure 5). It’s a lot easier to remove the right side chain guide with the primary pulley tipped in, because the pinion shaft gets in the way of removing the guide. Remove the chain guide and the primary pulley.

The chain guides on both sides are identical (figure 6).

The primary pulley has a shim on the front bearing.

Once you have the primary pulley off, release the pressure from the secondary pulley and remove the tool. Then remove the three, secondary pulley retaining bolts and pull the secondary pulley assembly out.

The secondary pulley has shims on the rear of the pulley assembly.

CLUTCHES, DRUM, AND PLANET

To get to the reverse clutch, you’ll need to remove the manual valve body and the small separator plate. There are four, 10mm headed bolts that hold it to the reverse clutch housing (figure 7).

Remove the housing support bolts; there are six bolts that require an E20 socket.

Pry the housing up and watch out for the two O-rings on the back. These O-rings seal the case passages.

The reverse clutches are on the back of the reverse housing. There are four clutches, four steels, one pressure plate, and a dished cushion plate. There’s an ID mark on one side of the dished cushion plate; it should face you when you’re assembling the clutch pack (figure 8).

Subaru’s technique for checking reverse clutch clearance is very confusing: They want you to add a weight to the clutch pack (using a special tool that doesn’t seem to be available), and then measure the clutch height. Remove the weight and measure height of clutch again. Add that number to your actual clearance and you should have 0.091”-0.106” (2.30mm-2.70mm).

But adding weight to the clutch pack doesn’t seem to make much difference at all. The clearance on this reverse clutch was 0.094” (2.40mm) and I’d reuse these clutches any day.

The pressure plate is selective if you need to adjust the clutch clearance.

Next, remove the ring gear, planet, sun gear, and forward drum. There’s only one planet assembly.

IMPORTANT: The sun gear is directional; if you get it in backward, you’ll lose lube oil.

The side of the sun gear that has the oil slot all the way around the gear faces the drum.
The sides with three slots face the planet (figure 9).

The forward clutch pack consists of three clutches, three steels, one pressure plate, and a dished cushion plate. The cushion plate has an ID mark that should face you when assembling the clutch pack (figure 10).

The clutch clearance for the forward clutch is 0.045”-0.055” (1.10mm-1.40mm. If you need to adjust clutch clearance, the apply plate comes in different thicknesses.

The last thing to take apart is the front differential and pinion support. To remove the pinion support, remove the fourteen E20 bolts and pry up. There are two seals you need to take care of. The rest of the front differential is just like all the other Subaru transmissions.

The front differential uses a separate fill from the CVT fluid; it takes GL-5 (75-90w) gear oil.

After seeing inside a transmission, it’s always easier to understand what’s going on. A simple teardown and description of this transmission goes a long way.

Now that you’ve had a look inside the Subaru Generation 2 CVT transmission, you should be all set to tackle this unit when one comes into your shop.

Thanks to Perfection Plus of Portland, Oregon, for the use of this core.