Tales From the Bench - January/February - 2019

JF015E: Common Issues

Over the last two years, we’ve seen a big change when it comes to rebuilding the Jatco CVT. It used to be hard to find the parts needed for rebuilding this transmission; that’s no longer the case.

One other issue we’ve seen is that the dealer reman transmissions have been failing and many of the warranty claims get denied by Nissan.

If you go with a dealer reman, make sure you have the unit programmed (recommend by Nissan) and use the OE fluid. Keep all records of this for your warranty, as it may be necessary for warranty claims. If you don’t have those records, there’s a good chance Nissan will deny any warranty claims.

Some of the common issues with this transmission are pressure and performance codes, and surging and flaring as the transmission goes from low to high range.

You can rebuild this transmission and make good money doing it. There are some basic areas to cover to make a quality repair along with performing the computer relearn. We’ll break down some of the more important points, to make this transmission repair a simple service for your shop.

PUMP AND VALVE BODY

Most common issues with all Jatco CVTs center on the flow control valve. The flow valve and its bore often wear at low mileage. Make sure you pull the valve out of the pump and inspect the bore and valve (figure 1).

There are aftermarket repair kits for this valve. In addition, there are several parts vendors that are selling new pumps or remanufactured pumps that have the bore repair already done for you.

As for the valve body, always pull each valve out and clean it thoroughly. Make sure you check for bore wear and make sure the valve moves freely in the bore.

The CVT often produces fine metal particles while it’s still breaking in. This fine metal causes the valves and solenoids to wear and stick at very low mileage.

One thing to keep in mind is that Nissan knows about these problems and they’re offering the valve body with solenoids very cheaply for some models; in some cases as low as $250.

If you see wear or think you have a solenoid problem, it may be best to replace the valve body. There are some TSBs that recommend a new, updated valve body that requires special programming, so make sure you search for service bulletins when working on one of these units.

PULLEYS AND BELT

The pulley and belts are where all the force is applied. These pulleys can have as much as 850 PSI applied to them at times. You need to make sure you inspect the belt and the pulley sheaves where the belt rides. The belt and pulley sheaves may look perfect, but don’t let that fool you!

Make sure you pull the pulleys apart. Those pulleys may have damaged rollers or balls inside. The pulleys slide up and down on these balls and rollers, but their main function is to keep the pulley from spinning on the shaft. There’s a lot of force on this area and wear is common.

The secondary pulley has a reluctor for the speed sensor to read its RPM (figure 2). These reluctors are pressed onto the pulley but they often come loose. The repair is simple: Just tack-weld the reluctor in three or four spots to hold it in place.

There’s a piston in the primary pulley that’s pressed onto the pulley sheave (figure 3). The piston becomes loose and looks like it spins and wears out. The center of the piston becomes egg-shaped and creates a crossleak (figure 4). This piston needs to seal on the pulley and needs to be press-fit onto the pulley.

Don’t forget to check all bearings for pitting and rough spots.

RELEARNS

You can build or buy the best transmission in the world, but that means nothing if you don’t finish the job correctly.

The Consult III Nissan scan tool has around seven different resets for their CVTs (figure 5). Some models have more and some less. The sad part is that many aftermarket scan tools have very few or no resets at all. Just because your scan tool doesn’t have the resets doesn’t mean you can skip the relearn step.

For the best possible service, you need to make sure you have the latest updated programming installed in the computer. But reprogramming the computer doesn’t mean the resets are done.

Some of the resets must be done with the scan tool, such as the G-sensor calibration, CVT fluid deterioration, throttle body calibration, engine brake adjusts, and steering alignment (some makes and models vary). Always check the factory service information to make sure you’re resetting the system properly.

On some models, you can run the Initialize TCM and Load Calibration Data with a scan tool or by performing a manual reset, as explained in the factory service information. This allows the ECM and TCM to reset and learn to talk to each other and start with new calibration data. Then the transmission can start learning.

But wait! Here’s one of the most important relearn procedures to save for the end. Clutch Point Relearn forces the system to relearn how to shift from low range to high range. Common complaints are surging, flare shifts, and sometimes dropping into neutral. This is a must-do relearn with all rebuilt, used, or reman transmissions or valve bodies.

The procedure takes around 30 minutes and is well worth it. Let’s get started and have a stopwatch ready.

  1. Start the engine and warm up the CVT fluid to 50ºC (122ºF). Confirm CVT fluid temperature by checking FLUID TEMP in the Data Monitor.
  2. Turn the air conditioner and other power loads off.
  3. Shift the selector lever to park.
  4. Turn the engine off and wait for 5 seconds.
  5. Start the engine and wait for 5 seconds.
  6. Turn the engine off and wait for 30 seconds.
  7. Perform step 5 and 6 two more times, for a total of three times.
  8. Start the engine.
  9. Shift the selector lever to drive.
  10. Accelerate from 0 km/h (0 MPH) to 65 km/h (40 MPH) at low throttle (0.5/8 – 1/8 as seen on your scan tool display).
  11. Coast down to 30 km/h (18 MPH) or less without using the brakes.
  12. Stop the vehicle and shift the selector lever to park.
  13. Turn the engine off and wait for at least 5 seconds.
  14. Restart the engine.
  15. Perform step 9 through 14 four more times, for a total of 5 times.
  16. Shift the selector lever to drive.
  17. Accelerate from 0 km/h (0 MPH) to 45 km/h (28 MPH) at low throttle (0.5/8 – 1/8 as seen on your scan tool display).
  18. Stop the vehicle and shift the selector lever to park.
  19. Shut the engine off for at least 5 seconds.
  20. Restart the engine.
  21. Perform step 16 through 20 four times, for a total of five times.
  22. Drive the vehicle and check that there’s no shock while shifting.

It may be a challenge for some shops to find a safe place to perform this drive relearn, but it’s a must-do with the JF015E Jatco CVT.

To sum it all up, for a successful JF015E rebuild or repair, make sure you repair the flow control valve in the pump, inspect or replace valve body, and never shortcut the pulleys. Inspect the piston in the primary pulley and tack weld the reluctor to the secondary pulley. Don’t forget to finish the job by updating the software and performing all the resets.

Do that, and the Jatco CVT will quickly become “just another day at the transmission bench” in your shop.