Driving down the freeway the other day, not speeding for once, and it feels like the car slips out of gear even though I was in automatic. Luckily I was around the corner from my local auto service so I coasted in. It's giving a P2704 error code which means Need New Transmission! Why is this happening in a car with less than 30k miles?? This is our fun car to drive (it's a convertible) and doesn't get driven far or for long. I'm at a loss for an explanation...... I was just having battery issues because it wasn't driven in 3-4 weeks and the doors weren't locked at the time. Took some time to charge it back up but it's been running fine since.

 

Confused--was it the battery that was causing it after all?

 

Haven't needed to replace the battery. Just thought that info might be pertinent to a mechanic.

 

The code could be from a low or failing battery. Erase it and try driving again.

 

If you were having battery issues fix that first. Battery problems will cause all sorts of weird problems. I had an '05 XK8 that started giving gearbox faults [similar XF transmission] when the car had 12K miles on it. Restart and it was OK.

From reading about the P2704 I don't see that it indicates a new transmission is needed. Did you get a "Limp Home" error message? That will limit the speed of the car and make it feel like the "car slips out of gear". Unless the problem is persistent, I would not worry about it too much.


P2704 Jaguar Possible Solution:
Vehicle Speed Sensor (VSS) Out of Self Test Range Indicates the VSS input signal is out of Self Test range. If the PCM detects a VSS input signal any time during Self Test, a DTC P1501 will be set and the test will abort. Noisy VSS input signal from Radio Frequency Interference/ Electro-Magnetic Interference (RFI/EMI) external sources such as ignition wires, charging circuit or after market equipment. Check for VSS input to be 0 mph when vehicle transmission is in Park.

 

Generally with any serious transmission complaint, my first choice of repair is a simple drain, drop pan, and renew pan/filter and fluid. In most cases this "fixes" a problem. In many cases the transmission pan will be relatively clean with few metallic particles attaching to magnets. This should be comforting. BUT, if the pan is full of junk, gunk and metal parts then you have a serious problem.

 

Actually, P2704 is:

Transmission Friction Element E Apply Time Range/Performance - Mechanical Failures

Check and correct oil level. Clear DTC. If code re-detects, suspect Transmission (Gearbox) internal fault. Install a new Transmission as required, refer to the new module/component installation note at the top of the DTC Index.

So, first step is reset the DTC and see if it comes back. 'Friction Element E' is a clutch that drives the planetary gear carrier. I think it would be worth getting a ZF expert to check it out. Although the Jaguar solution is "Fit a new transmission", that's because they don't repair transmissions - it may be repairable.

 

Its worthwhile noting these trannies are as hard as they come.

 

My mechanic told me that most transmission issues are related to software and sensors...so get another opinion from a person experienced with these transmissions.