2012 x351, driving about 4 years. It drives ok . The weired thing is , if you parked it without apply the E brake. the next time , after restart and shift, it is perfect fine. Also if you put gear selector to N before put into P directly ,and let the car bouncing slightly back forward, after that ,you can select P and apply the E brake. It will work fine the next time. But if you stop the car ,put it directly into P and apply E brake right now. then ,There will be a loud clunk when **** from P to D after restarted. So I just ignore the E brake everytime when I parked the car. But It'll be a disaster when parked on a slope place you have to apply the E brake. I am just wondering anything wrong with the car causing the phenomenon, it just driving fine, shifts smoothly, even maneuvering on a slope, no clunk at all when shift from D to R back and forth.

 

Hello and Welcome!
The clunking sound you hear is the noise made by the gear selection motor. The motor is working hard because the pin holding the transmission in Park is under the strain of the cars weight. This pin (or "pawl" as it's correctly known) is only designed to prevent the gears from turning, not to support any weight. Under these identical circumstances in an older car, you would struggle to move the gear selector lever out of Park.
When you correctly bring the car to a resting position by shifting into Neutral, applying the parking brake, then removing your foot from the foot brake, allowing the car to move slightly fore or aft and being held by the parking brake, only then moving the selector to Park, you won't hear any noise whn getting underway later.
Those of us who learned to drive on manual transmission cars, or in a hilly area, discovered this procedure early in our training.
Unless you are parking on absolutely level ground, follow the procedure above and your clunking will cease.

 

Thank you for the help explaining. As my understanding , it's just the pawl in the transmission get too much play or get tired ,So nothing I can do to improve it. Also be curious，this symphtom found just on some rear wheel drive velhicles . not on front wheel drive cars even it's high milage as well. old rwd cars really painful

 

Same happens on front wheel driven vehicles. When locking pin or pawl (depends of transmission) are enagled and vehicle weight are set to powertrain; all rubber bushes, including engine and transmission mounts, are bended under tension by weight of the vehicle. Deeper the hill, more tension. You can see this by parking non-level with your hood open and see how engine will tilt when weight it set to powertrain. When released by moving from P, all this tension are released and force are throwed backwards thru gearing, moving free tolerances from other side to another.
In most cases an helical type of gears do not give sound, unless they have big play, usually its the differental pinion gearing giving the sound. There are nothing to do for it, since they should have play for heat expansion tolerance. The gearing will not harm by this, but the locking pin or pawl are not made for heavy stress, so use parking brake before set transmission to P when park on non-flat surface.
On rear wheel vehicles the sound can be louder, because hollow propsaft can act as "amplifier" echoing the sound, but its not written on stone. Front wheel driven vehicles have thinner oil for differential gears, since these gears are inside of gearbox, when rear wheel driven vehicles have thick oil in rear differential unit.

 

I think I was wrong about this. Unlike many (most?) cars of this era, ZF "6HP" transmissions do not have a motor pulling a gear selector cable. Rather, the parking pawl is an electric solenoid inside the transmission. All gear selections are done electrically. The clunking sound you hear is not a struggling motor, but a solenoid protesting. A painful sound, nonetheless. Can't be doing the gear oil any good, either.

The "motor pulling a cable" design is much more bizarre. Took this poor guy many hours to diagnose and fix:

 

Had the clunk in my XK when I moved gears Jaguar replaced transmission with a new one under warranty.

 

Hey, I like watching this guy's diagnose program either, I mean he's so carefull writing down everything on a notebook ， and did everything so seriously. respect that.
Also there is a strange thing happening in my car I want to mention. Everytime when driving to a stop . The car will still going forward a little bit when you release the brake pedal right after rotate the knob from D to N. Scared me drove it the first time,you know ,when stopped at the red light, there are cars there up front .feel almost hit someone now I am carefully holding the brake padel after gear shift for maybe half a second until the accumulate force released ,then I can step down from my brake pedal safely. But this thing dosen't happen to other cars I drove since then.Anyone have this problem? I am wondering if it related to the clunk sound. I mean ,if my Jag would not produce the force after shift from D to P. The powertrain will be also in a relax sitation and I don't need to release it to the car body by bouncing . There will be no clunking sound, right ? just my guessing. Also apologize for my poor writing. hope I don't make you painful when reading

 

I am not clear?
Why are you shifting into N when coming to a stoplight?
Maybe I miss-understood what your saying?
If the car is in N it could roll forward or backwards depending on where the car is sitting?
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There is plenty you can do to solve this. It's a design element of the x351.

You just need to pull the e-brake first, then shift from D to P. That's how it should work and shame on Jaguar for not putting that in the manual for at least minimum reference.
That way the parking pawl/pin assembly will not be doing mechanical work in holding your vehicle in place. It's not designed for it, and if it breaks/fails, then you'll be in bigger trouble.

 

Its my bad not speak clearly. What I mean is ,when drive to a stop light, where the ground is very flat , I used to put gear from D to N and let my foot have a little rest.It works fine on all the other cars i have droven. /But /the jag seem to have a slugsh shift solenoi or something, It can keep going after shift to N for about half a second. So I have to keep press brake padel until it finished shift neturl and calm down or it could be dangerous.

 

It's quite what I thought and did the first time, but on the contrary, I have to put to N or P first ,second release brake padel waiting until the car finished bounce a little , and finally engage the parking brake (or not if parking in my garage, flat ground. too complex doing this everytime),then I can avoid the clunck sound next time.It just work not the same way other cars do. What I feel painful is it doesn't work at slope either cause I have to apply parking brake at the first time before I release brake pedal ,feel kind strange but don't know what's going on my car

 

One other thing I noticed is that if you put on the EPB with the car in D. The EPB will apply but if you move or touch the gas pedal the EPB releases automatically. I did not know that when I started messing around with the EPB.
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