Leaky Cat

July 29, 2019

This bulletin applies to 2018 Jaguar XJ vehicles equipped with a 5.0L supercharged engine and automatic transmission. The transmission oil may leak, resulting in transmission sump replacement.

To correctly diagnose and repair, carry out the following steps:

1. Raise the vehicle on a hoist.

2. Using a suitable degreaser, thoroughly degrease the suspected components all the way around, as well as about 1-2 inches above the suspected leak.

3. Using an air gun, make sure that all traces of oil are removed from the bolts attached to the sump pan.

4. Using a suitable leak detector spray, thoroughly coat the suspected component as well as about 1-2 inches above the suspected leak.

5. Allow to sit for a couple of minutes to ensure that all oil has been cleared off.

6. Take a clear, in-focus photo of the spray on the suspected area before proceeding.

7. Road test the vehicle, allowing the engine and transmission to reach normal operating temperatures.

8. Return the vehicle to the shop and raise it on a hoist.

9. Inspect again for leaks. The detector spray should leave a trace from the leak area.

10. If a leaking point has been identified on the sump pan, take a clear photo of the leaking position and proceed to Step 11. If a leaking point has not been identified, proceed to Step 12.

11. At the customer’s convenience, raise a TA (technical advisory), attaching photos of the sump pan, requesting a visit from ZF MS engineering. The TA will advise whether to proceed with the repair or whether a ZF engineer will visit the site.

12. If a leaking position has not been identified, check the following areas:

  • Check technical bulletins, referencing automatic transmission leaks.
  • Inspect the transmission output shaft seal.
  • Inspect to determine if oil cooler pipes are not secured correctly.
  • Check the transmission electrical plug.

13. If a sump pan replacement is required, record the break-away torques for the sump pan bolts.