Good Evening (at least where I am),

I am new the the Jaguar world having purchased my 2010 XKR last summer. Since aquiring the car, I have been fixing various issue (Suspension Bushes, Supercharger Coupling, etc.). Most recetly I have been working on the transmission as it had an issue shifting from first to second gear. In general the shift was sluggish under light throttle but under heavy throttle it would just slip and not engage second at all. I figured I'd take a crack at rebulding the mechatronic valve so I got a zip kit, new ZF solenoids, gaskets, seals , etc. The valve body itself looked to be in good shape and the rebuild / reinstall went off without a hitch. During the fluid refill process, I started the car, up popped a transmission fault on the dash, the shifter neatral (N) light flashes and cannot moved the sleector out of neutral. The code it throws is P0771 (Shift Solenoid "E" Performance/Stuck Off). I have cleared the code and tried the hold the gas pedal down transmission reset to no evail. I pulled the valve back out a did a visual as well as removing / ohming out and replacing all the solenoids. Put the valve back in the car and same issue. Looking to see if anyone has any insight or experience with this issue. Observations during dissassembley were the car wwas about 2 liters low (there are no leaks) and the fluid was very dirty despite the previous owners records showing it was changed 500 miles ago. The car has 66K on the clock.

Thanks
Steve

 

Did you have to split the valve body to put in the zip kit

 

Hi scottjh9, Yes, I split the valve body to replace the gasket.

 

Fuzzy, A few tips.

As far as I can tell, the pedal hold-down, if it resets anything, resets some superficial conditions. Fully resetting the ZF requires SDD, using the transmission adaptation reset function therein. There may be resets available through other OBD tools, but since I've only used SDD for this function, I can't speak to others. This full adaptation reset is required whenever you change parts or the fluid in the ZF. Then you complete a driving sequence to retrain the ZF when to shift properly. My ZF (28 model) was rough shifting in lower gears. I found a quiet road on a Sunday morning. I used my laptop with SDD to reset the ZF adaptations. Then I did a routine similar to the one below. It worked. Shifts are smoother throughout.

"Since buying the car in March 2018, my XJ TDVi 2.7 with the ZF6HP26 box developed 'the lurch' (on slowing down at junctions then accelerating away, it would hesitate and jerk into gear). On looking into the cost of a full gearbox flush and refill, before spending £600+ I decided to try resetting the drive cycles myself by following a procedure in a Jaguar technical bulletin that I'd come across online. I printed the instructions but I've been unable to find them again since, although I've not had time to have a proper search to be honest. Anyway, I followed the instructions to the letter and so far the results have been very satisfying. The car no longer seems to have the lurch, and all gear changes seem smoother to boot. Here's what the bulletin advises:

Run the car to normal working temperature (transmission oil should be min 60 degrees C). Do not perform procedure in Sport Mode. From standstill, gently accelerate from 1st to 2nd making the change up at between 1300 - 1800 rpm. Follow this process through 2-3, 3-4 and 4 -5 at between 1300-1800 rpm and gently accelerate to 50mph in 5th gear. Gently apply the brakes until the car comes to a standstill and hold on the foot brake for at least 15 seconds. Do this same procedure at least 5 times.

I did this 7 times to be sure, and the gearbox is transformed. I will get the gearbox flushed and serviced next year anyway, as the car has just turned 71k miles and it's probably on its original oil. This process worked for me so hopefully it might be helpful to others with the lurch, before spending a fortune."

Second, there is a very specific process for filling the fluid on the ZF. Use https://offroadrover.com/check-zf-6h...t-thermometer/ This one also has a variant on the re-adaptation procedure.

Fluid: Use ONLY fluid meeting the Shell 1374.5 spec. If it doesn't specifically say so, don't use it. Don't use "universal" fluids. ZF LG6 is the right fluid, but expensive. Mercon SP is also the right fluid, but a different color and cheaper. There are others that meet the spec. I use LG6, because I expect to only change the fluid at 60-70Kmi, and 120-140Kmi, for the life of the car. If I do go another 60-70Kmi, I'll change it a third time. Approximately 7 liters are needed, so that's around $140 in fluid if I use LG6. Cheap.

And, the presence of low, dirty oil means the PO flogged it, and certainly lied about changing it. I drained a ZF on my BMW after 75K miles, and the fluid was medium amber. Black fluid means likely damage due to excessive heat and clutch particles.

But to the specific matter, I'd split the mecha and doublecheck the zipkit process. You might have missed a valve ball or something equally small. Also, confirm you have the right separator plate -- there are variants.

One more thing. I've read numerous places that the E clutch is a weak spot on the ZF and an early failure point. No direct experience, though.

(Note there is an excellent, low cost OBD tool out there for the X150, called the Autel AP200, with the JLR software download. It has many useful tools for the car, some effective for all models, some only for the 5.0 models. I don't believe it has a transmission adaptation reset, though)

 

the reason i ask is because the seperator plate can leave little bits of the sealant in the passages and wind up on the solenoid screens. Also i read a post some time ago related to the 6hp26 where one of the checkballs got out of postion upon reassembly and caused a similar problem. I am not familar with the 28. I think 2 major diffs might be e shift vs manual linkage and of course 2 extra gears. As stated by pantera a reflash of the tcm software via sdd would be a good start

 

panthera999 and scottjh9,

Thank you for the replies and thoughts. I bought a copy of SDD and the associated cable and was waiting for it to arrive. Well it has and the install to my laptop has been less than straight forward. Was hoping to do the reset this week but best laid plans... I will do a gearbox reset with SDD to see if that clears the issue before deciding to tear back into the transmission/mechatronic unit.

I was very careful in the teardown, cleaning and reassembly of the mechatronic unit so I think its lower probability of is being gasket or misplaced check ball. The gasket I took out was actually in good shape and I compared it to the new one so I'm confident it was correct. In fact the mechatronic unit, gaskets, seals and solenoids looks in great shape so suspect the issue lies elsewhere unfortunately.

I have the receipt for the trans fluid change with the VIN so it was definitely "done" but definitely done wrong. I used ZF fluid but can't speak for what was put into it when it was changed by the PO.

Given the fluid condition and how poorly it was shifting to start with, leaning toward taking it out and replacing it but we'll see what happens in the coming week.

 

scott, just a quick note to tell you that the ZF Transmissions we all have in the x150 are 6-speed. You mentioned "two extra gears", that is not the case with these Transmissions. The 28 designation is an indication that various parts of the transmission have been strengthened to allow for higher torque. Good luck with your work.

 

thanks for the clarity on the two. I guess 8hp designates the 8 speed

 

Good catch @panthera999
in layman’s terms:
https://en.wikipedia.org/wiki/ZF_6HP_transmission

 

Hi Scott. New the forum where you able to solve your Transmission issues. What ended up being the problem. Thanks

 

in the end it was new denso coils and plugs that fixed everything. In a nutshell the tcm was getting info from the ecm that it did not like at higher rpm or a downshift. The ecm never had codes except for canbus failure due to the tcm putting vehicle into limp mode. At the tail end of this saga the tcm finally gave a checksum error code and basically i got lucky. I do have a very nice R transmission with converter in my shed now. Only 69,000 miles with converter. Very hard to find. The entire 3 year saga would be a very long read and a long write from my perpesctive to keep the timeline intact. Bottom line is very subtle engine troubles can adversely affect the tcm and send a guy in circles when no codes are present until the last 6 months

 

As I look for a replacement transmission, does anyone know if there are any differences between the ZF6HP28 in the 5.0L XK and XKR?