Tales From the Bench - August - 2019

Pulleys and Chain Installation: JF017E

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Jatco CVT transmissions have always had a belt to transfer power from one pulley to the other. The belt has worked out in light cars with small engine torque but has some limitations. Now with the slightly bigger engines and more torque demand, Jatco CVT transmissions use a steel chain instead of a belt. The chain allows for increased torque rating and durability. Let’s take a look at how to remove the chain safely.

Just like other Jatco CVT transmissions, start by splitting the transmission in half. The rear cover houses the pulley assembly so that’s the side we’re going to concentrate on. After the assembly is out, remove the six pulley-retaining bolts from the rear cover.

Attach the Posi Lock TJ-1 puller, or equivalent, to the Secondary pulley (figure 1). Remove the chain tension with the puller by compressing the spring on the Secondary pulley. There are two chain lube tubes that clip into the chain guides. Remove the two aluminum chain lube tubes.

The four chain guide halves are all the same so don’t worry about mixing them up. To remove the chain guide you’ll need to unlock the four locking tabs that hold the two halves together (figure 2). Use a small screwdriver to release the locking tabs while gently prying the two halves apart.

Please note the primary pulley may or may not have a spring. If the pulley has a spring, the force of the spring can cause bodily injury if care is not taken.

When removing the Primary pulley, tip the pulley out of the chain (figure 3). When you do this, you’ll need to be very careful not to side load the chain and also keep an eye out for the speed sensor exciter on the back of the pulley. If you bend a tooth on the exciter it may cause performance issues and codes. If you have a spring in the primary pulley it may be easier to take both pulleys out of the rear cover together.

Note: In the rear cover there is a shim on the Secondary pulley side. Do not lose this shim.

There’s information on the ATRA tech repair center for more detailed pulley disassembly. For this article we’re going to keep it simple. Figure 4 shows a breakdown of the primary pulley.

First step is to remove the 46mm nut. Then remove the bearing with a puller. Once the bearing is removed, remove the bearing retainer and exciter wheel for speed sensor.

Note: Partially reinstall gear and nut for safety. This is an important part of the disassembly.

Pull on the primary pulley sheave with puller until the piston pops off the main pulley shaft. Remove the three rollers and keyways. Inspect the pulleys, chains and components for wear and damage. Next, clean the parts, replace the seal ring and reassemble the pulley.

First remove the 40mm nut. Using your puller remove the bearing and gear, then remove the large snap ring and cover. Figure 5 shows a breakdown of the secondary pulley.

Note: Partially reinstall gear and nut for safety. This is an important part of the disassembly.

Pull on the secondary pulley until the piston is loose on the shaft. This spring has a good amount of force so watch out and keep your fingers clear. Inspect the pulley, piston, bearings and the three rollers and grooves. Clean components, install new seal ring and reassemble the pulley.

INSTALLATION OF PULLEYS

The JF017E pulley and chain set up is a little different than normal CVT belt set up because the chain assembly uses the chain guides and a lube tubes.

We need to install the pulleys and chain into the case without the lube tubes, then install the lube tubes later. Let’s go over the process.

The rear cover has a shim and seal ring for the secondary pulley (figure 6). Attach the Posi Lock TJ-1 puller to the Secondary pulley and open the pulley by compressing the spring. Inspect the chain, look where the chain rides on the pulley and make sure there is no scoring or wear.

There are two chain guides equaling a total of four halves, all the halves are the same. Install the guides onto the chain, the tabs that clip onto the chain lube tubes go to the inside as shown in figure 7.

Install the chain onto the secondary pulley. If the primary pulley does not have a spring inside the pulley, install it into chain. The primary pulleys that have a spring are more challenging to install onto the chain because the pulley is closer together due to the spring tension. What you can do is open up the pulley and wedge a piece of bushing with a zip ties to keep the pulley open (figure 8).

HOW TO MAKE THE TOOL

Take a bushing about one inch wide and cut a moon shape about one and a one half inches long. Drill two . inch holes so a zip tie can be attached to the bushing. The zip tie will later be used to pull on to remove the bushing from pulley.

Prior to installing the chain and pulley assembly, screw two alignment studs into each bearing retainer. This will allow you to align the retainer to rear case. As a complete pulley assembly, you can lower the pulleys onto the rear cover (figure 9). After you get the pulleys fully seated in the rear cover put one bolt in each bearing retainer.

If you had a spring in the primary pulley, make sure you pull the tool out of the pulley at this time. Remove the Posi Lock puller and install it in the case.

When you’re done rebuilding the internals and the front case is installed, remove the bearing retaining bolts that hold the pulleys to the rear cover. Put the transmission bellhousing side toward the bench with rear cover facing up. Carefully remove the rear cover while leaving the pulleys in the transmission.

The chain lube tubes have a hole in one end that slide over a metal tube in the transmission (figure 10). The tube also has milled flat sides so the tube does not rotate. There’s a large round tab on the lube tube, it always faces the chain. Install the rear cover and the pulley assembly is done.

The JF017E with the chain has a different pulley installation process then the belt driven CVT. With all the different models and changes on the Jatco CVT transmission it’s hard to keep up sometimes. The CVT is common now in most shops, I wonder what is going to be the next change?