Flywheel XJ6
Edit:

I have replaced now the torque converter with another used one (was included in the from me bought used gearbox).
The cycling is gone now, totally.
So if you have a clean gearbox and it is still cycling in cold, replace the torque converter.
In Germany a new one costs 560€+ taxes at Zf or approx. 400€ on eBay.

I'm happy now and I hope I can drive it now for a long time on long distances.

To change the torque converter (TCC):

Release the screws before catalytic converter to the engine, release the screws from the driveshaft, mark the position of driveshaft, gearbox and rubber connector between with paint, so don't mix it up.
Use a suitable gearbox lifter, make sure the oil pan is well supported. Remove all bolts between gearbox and engine, but leave one or two in the threads for safety reason, remove the bolts of the starter and disconnect the big connector above the gearbox. To reach this and the upper screws, you have to remove the bolts of the gearbox support on the backwards side of your gearbox but be careful and lower the gearbox with the hydraulic lifter.
After disconnecting the gearbox and engine, you can disconnect the torque converter from the flywheel via loosening the screws between flywheel and tcc, be careful not to drop it.
When you install the new tcc, you have to put it on the gearbox shaft and bring the knob into the middle of the flywheel, be careful again and press it carefully into the hole of the flywheel, so it's centered. After this, do everything in reverse. Afterwards refill oil to the known method (40°C, until some oil Drops out of the hole on the gearbox).

 

Very impressive!

You have all the equipment and the confidence!

 

Frankly, today I doubt in this. That is because I've recently changed valley hose preventively and thus had to use all new gaskets in air delivery system including cleaning throttle body and its surrounds resulting in decreasing air leaks and overall better engine work. I also changed egr to not to dive there anymore. I was confused before that official jlr troubleshooting guide always related to engine first then to transmission and only in firmware aspects. I couldn't understand why engine's health influences first on transmission behaviour and believed that only transmission repair can fix these issues in the roots. I drive for three weeks now on serviced engine and transmission operates very smooth i'd say unnoticeably as well as overall performance noticeable increased, better say back to its factory numbers.. maybe) I had all these famous lurch, cold TCC hesitation, 2-1 heavy shift, D and R bump engagements etc.. but for now all is gone. Sure i cleared, relearned, changed oil etc with temporary enhances before i serviced the engine and i didn't even have to clear and relearn anything again. Everything started to work as it engineered )

 

The engine has to be made to be working properly (e.g. no air leaks) because its computer (PCM) and that of the trans (TCM) constantly exchange messages in order to manage shifts smoothly and so on.

They are on the CAN so many messages per second can be sent.

 

Hi, Looks like I have an air leak, but I can not find it. I have sprayed on the air hoses with brake cleaner, and the values did not change. Gaskets to the main inlet manifold are renewed.
The only thing left is ever valve, pcv Valve is new.

Ever is sitting directly in the throttle body at the XJ6? I have seen it on other ford engines as V6.

 

My lpg system wrongly adjusted, the fuel trims do not run in idle as they should, so if the engine is going in idle, the values don't fit and go extremely into the opposite direction up to 20%. So if the engine adjusts itself, it also takes a few milliseconds, but the shifting also takes up to 400ms I guess and if the load or mixture doesn't fit, it shifts not good.
rpm cycling went down, but switching on of TCC is not at the exact point. Air leaks are not present.
I can switch between gasoline and lpg and will test it further next days.

 

For what it's worth I get the gearbox fault after starting from a jumped dead battery. I was stuck in 2nd gear for a few miles before deciding to pull over and restart. Problem went away. Battery problems seem to effect so many things

 

5r110, 4r100, 6r140, zf6hp's, zf5hp's most mercedes 722.6 and up can all use global and it is extremely reasonable!

 

majority of ZF units with tcm on board or on the valve body are vin specific. If your talking Megatronic, there are hacks available you have to search and we have been unsuccessful in flashing or reprogramming certain valve bodies in ZF units. We have done 100's of these. Peter Schmidt in The San Francisco Bay area is the expert in the US I would seek any information about. The Father Wolgang recently passed but his son has picked up where his father left off. They are highly recommended sources of accurate information on any ZF or Mercedes transmission issues.