Yes, the engine must be running or you'll not have enough fluid in the transmission. Vehicle level is important along with the correct transmission fluid temperature. It is also recommended clearing the transmission adaptation as it will need to learn shifting with the new fluid installed. Gotta wonder what they were/are thinking of having to fill the trans from underneath the vehicle. What a PITA. Here's a link to the procedure:
ZF 6HP26, 6HP28 Transmission Fluid Service Procedure
Another reason to buy a GAP IID tool. There is a trans fluid temperature window I was able to watch while under the vehicle (via Bluetooth).

 

GAP tool? What is that? Spark plug gapper, there is a GAP tool in adobe InDesign. Neither apply to transmissions.

 

It is a diagnostic tool. He is using it to see live data.

 

Seems to me you would get LESS fluid by heating it up.

Most fluids expand when heated. So changing it out at 60F to the fill line would actually overfill the hole if heated to 110F, it would expanding like heating water in a pan.

Or maybe the real reason to run the engine is get the pump running to put the fluid in different nooks and crannies and has little to do with the actual temperature.

 

The primary reason is to pump fluid through the whole system. The caveat is that you cannot let the fluid get too hot or you will undefill the system.

 

Did you find a solution? I am reading up on this as much as I can. Seems like a big job.

 

I could be he needed to buy a new tranny and is too upset to share his pain with us.

Sometimes people change the tranny fluid in hopes it will save a failing one. It can actually make slippage worse if the only thing holding the plates together is grit.

Or it could be he used the wrong fluid and its slipping. or maybe he simply underfilled it and just needed more.

Its a messy job. The shop that did mine soaked the cross members in oil so I can't tell if I have a 1 drip a day leak or its just the excess mess oil that has been dripping off from my cross members.

I would probably only do it if I had my own lift. Landrover (FORD) seemed to go out of their way to make accessing the pan difficult. This sealed for life crapola was just for marketing and saving costs on dipsticks and other parts.

The only way to check the fluid level is to crawl on back remove a hard to access plug and let it drip on face. Really? On a very important part of the car? Seriously Landrover?

 

Update: Saw on another forum the possibility of the shift linkage binding. $30 and 20 minutes later, shifts perfectly. The linkage must have rusted in place while truck was sitting for a few weeks, and it would pop out of gear, mimicking
perfectly a slipping trans! Also, shifts much better now with the new fluid,.....now that the trans stays in gear!

 

Yes....had read all the business about checking temp of fluid with a heat gun, and trans re learing to shift.....and actually, worried about all of this for a while, until found on another forum, someone whose shift linkage was binding,.....$30 kit took 20 minutes to install....and shifts perfectly. The binding linkage was popping the trans out of gear, which mimicked perfectly a slipping trans. Now that it stays in gear, with the new filter and fluid, its shifts much better....all that stuff about relearning, and getting the temp just right,....ended up being a distraction.

 

The whole temp thing, while am sure is true,.....ended up having little bearing,...it turned out to be a binding shift linkage,...$30 kit and 20 minutes.....
now vehicle shifts fine. Had thought the whole relearing thing was a bit overblown, but the trans did shift fine sometimes, then it seemed to slip....but that binding linkage mimicked a slipping trans perfectly!...once it was replaced, trans shifts better than it did before!