The Word On The Street - December - 2016

The Mystery Behind Nissan/Jatco CVT Pulleys

There’s always a bit of mystery the first time you work on a Jatco CVT about how to take the pulleys apart. Everyone’s heard about the very strong spring in one of the pulleys, and how and you have to be careful getting it apart to avoid getting hurt or damaging the pulleys or other parts.

In last month’s issue of GEARS, we discussed how to remove and replace the belt or chain from these pulleys. We also showed how you can use a simple and inexpensive two-jaw puller on just about any CVT to make it easier to disassemble these pulleys. You can use the same tool to disassemble almost any CVT pulleys you work on, Nissan or otherwise, because the puller jaws’ gripping edge won’t damage the surface of the pulley sheath. 

In this article, we’ll cover some Jatco pulley comparisons and precautions, and you’ll learn how to disassemble CVT pulleys safely.

First, let’s look at the secondary pulleys. The secondary pulley is the one that always has a strong return spring. There are some CVTs — those used behind larger engines — where the primary pulley also has a spring, although it usually isn’t as strong as the one behind the secondary pulley.

The secondary pulleys seem very similar from model to model (figure 1). The pulleys primarily come apart the same way, but there are some precautions you need to take on certain models. The example used in this article is the secondary pulley in the RE0F09B.

First, remove the retainer nut. This is a left-hand threaded nut with no identification marks. Use the two-jaw puller to remove the output and park gear (figure 2). This is only one method; obviously you can use any combination of tools with a gear puller to perform this part of the disassembly procedure. The reason we’re using the RE0F09B for an example is there’s one difference on this model that isn’t on other models: It has two half-moon shaped retainers under a retainer shell (figure 3).

With the retainer nut and park gear removed, you may think it’s time to begin pulling the apply piston and sheath off the shaft. The sheath will start to move and then stop when the return spring is completely collapsed. At this point the apply piston and retainer shell are held in place by the two half-moon retainers located under the shell. You’ll need to remove the snap ring to lift the retainer shell off first to access the two half-moon retainers (figure 3).

Now you can remove the apply piston, which is press fit onto the shaft, and upper sheath (floating) off the secondary pulley shaft. Then place the park gear onto the secondary shaft and, by hand, thread the retainer nut back on.

With the two-jaw puller installed on the outer edge of the upper sheath, pull up on the upper sheath until the return spring collapses against the apply piston. The apply piston will jump up and hit the park gear (figure 4). It’ll be quite a pop due to the strong spring.

That’s all there is to it; the pulley assembly is apart. To reassemble, use a press. The exploded view (figure 5) shows the order to assemble the components.

When used with larger engines, the RE0F09B primary pulley assembly has a return spring that isn’t in other CVTs. This return spring is much weaker than the one in the secondary pulley. The primary pulley assembly also has two half-moon retainers, but there’s no retainer shell. You’ll see these retainers easily once you’ve removed the bearing (figure 8).

The procedure to disassemble the primary pulley is similar to the secondary pulley. After removing the retainer nut (right-hand thread), use a three-jaw puller or compatible tool to remove the bearing and pulley retainer (figure 6).

Remove the half-moon retainers and reinstall the retainer nut, leaving it hand tight. Use the two-jaw puller tool to pull up on the apply piston and sheath until they pop up like they did on the secondary pulley assembly (figure 7). This one won’t spring up as abruptly as the secondary pulley because the return spring is much weaker. In fact, you could simply tap the assembly onto a hard surface like a cement floor and the piston will fall right off onto the retainer nut.

Whether there’s a kit available or not, always take the pulleys apart to clean out any debris inside them, and to check the sealing rings for damage to be sure they’ll seal and the piston will apply well and not slip. The checkball-type bearings found on the shaft (figures 5 and 8) are known to fail; inspect them carefully. Missing this step will be a gamble: The transmission may not perform correctly: it could slip, or the bearings could fail (figure 9).

Be careful assembling the bearings back into the round groove of the pulley sheath:

  • Install the lower bearing retainer ring into the pulley sheath.
  • Align the round grooves of the pulley with the round grooves on the shaft.
  • Install the bearings.
  • Raise the pulley just high enough to install the upper bearing retainer ring.

The most important thing to remember here is to place the raised tab or bend on the top and bottom bearing retainer ring into one of the square grooves in both the primary and secondary pulley (figure 10). If not placed into one of the square grooves, the bearing retainer ends won’t align correctly, leaving one of the round grooves to remain open. This will allow the bearings to move out of position on the shaft.

If you install the retainer ring incorrectly in one of the round grooves, it’ll leave one end open and won’t retain the bearing (figure 11).

Hopefully this has cleared up some of the mystery on these Nissan/Jatco CVTs. We’ll look at more about CVTs in future seminars, bulletins, and GEARS articles.