I located the post and thread in the other Jag forum https://www.jaguarforum.com/showthre...=1#post1078737
These are supposed to be the steps to flush the trans with the Launch machine:
1/ Connect to car
2/ Flush the system
3/ Drain 4 litres using the machine
4/ Drain the rest (1 litre left total) and drop the sump pan
5/ Remove Mechatronic, change square seal and finger seals ( not ever advised finger seals before )
6/ Replace Mechatronic unit and new sump and wiring seal
7/ Refill, before starting the car with 4 litres of your fluid. The ATF Machine does this.
8/ Exchange 9 litres of fluid, bearing in mind you have a new sump full and are running 1 litre light (this is usual)
9/ Top up the litre with the machine until it spills over the level plug.
10/ Disconnect and test drive once all back together.

I believe steps 2-3 are useless or even dangerous. There is no need to introduce anything else than the correct fluid in there and these transmissions are not full of gunk. Also draining the 4 litres with the machine would involve fluid come out of the trans and nothing go in? Why not just drain and remove the pan? Then I would use step 7/ to push less than 1 litre to wash the clutches and then remove the Mechatronic. Once everything is reassembled, I would use step 7/ to fill with more than 4 litres. Fill until it starts dripping out of the fill plug and than exchange the fluid in the converter. Before starting the TC flush there is new fluid in the sump and, except a few ml of old fluid in the valve body, drums, clutches and galleys, there will be no fluid mixing since the TCC is open at idle and all the fluid from the converter goes out to cooling before returning to lubrication. But yes there is a lot of mixing in the torque converter even though the clean fluid goes behind the TCC so the more fluid used to flush the better. That is the reason I tried to flush the converter using the WK AUF port just above the cooling port on the side of the transmission. Complicated but seems to waste less new fluid and about 13 litres in total are enough. More info here ZF 6HP19A tiptronic gearbox (A6 3.0 TDI Quattro) - Page 34 and here https://www.sonnax.com/tech_resource...ns#close-modal

Again, tomcoo's method is the best in my opinion but run it only for about 20-30 seconds to exchange about 6 litres. https://www.jaguarforums.com/forum/x...3/#post2147409 . Cut a hole in the old plastic pan once you remove the filter, run the hose through and the drain hole will also be smaller and manageable.

If using Don's or the machine method, cut or replace the rubber portion of the cooler return line and install a 1/2" Magnefine inline magnetic filter that will also make it easier to flush the fluid in the future. Why did Jaguar decide that cutting weight by using aluminium trans lines and no intermediate connections is beyond me.

 

If I were starting over I would do it differently. I never realized how much wasted new fluid was involved in Don's method. In Don's method the more fluid exchanged the more new fluid is wasted from the mixing of original fluid with the new fluid within the transmission. In total I used 18 liters of Jaguar transmission fluid. With each additional liter exchanged more of the new fluid pumped in is also removed than the last liter removed--a very expensive procedure. Many transmission shops advised me not to drop the Mechatronic and replace the sleeves I'm only doing this to replace the fluid. I only replaced the pan/filter before changing the fluid. I've probably achieved > 80% <90% removal of the original fluid. Although the process was expensive I believe my transmission is better for in than having 100% of the original fluid churning around in it. I'll do another change in 4-6 years.

 

Hi DGL,

I typically need 11 to 12 liters of fluid to perform a flush on a 6HP26, depending on whether the engine is normally-aspirated or supercharged. The most fluid I have ever needed was around 14 liters, on a car that was 3 liters low on fluid to begin with. I'm not sure why you needed 18 liters, and at Jaguar-branded fluid prices that was certainly expensive. That's why most of us are now using Motorcraft Mercon SP instead of ZF Lifeguard 6 or Jaguar-branded Lifeguard 6.

The cooler line flush has certain distinct advantages and is regularly employed by transmission shops around the world. For owners of Jaguars with the ZF 6HP26, an important advantage is that the flush can be performed without removing the pan/filter. This is especially useful under certain commonly-faced circumstances, such as when trying to determine whether worn fluid is the cause of, or a contributor to, harsh shifts, slipping or other malfunctions. When a car comes to me exhibiting harsh shifts or slipping, I want to first determine whether replacing the fluid, and if necessary, clearing the adaptations and updating the firmware, will resolve the issue. If these procedures do not resolve the issue, the transmission may have internal damage and will require further diagnostics or a rebuild. My thinking is that it's best to avoid the time and expense of replacing the pan/filter and other parts until we know where we stand. If the transmission responds well to the fluid change and firmware update, then it is a simple matter to replace the pan/filter, sleeve and seals, and to reuse the new fluid drained from the old pan (I capture it in a clean catch pan and pour it through two stacked paint filters before reintroducing it to the transmission).

The principal advantage of the pump inlet flush method is that it eliminates the mixing of new and old fluid in the pan. But since the pump draws fluid from the bottom of the pan, and the new fluid introduced at the cooler line port spills on top of the old fluid in the pan, the amount of mixing is really minimal and, in my opinion, should not be fretted over. If the transmission is operating properly and the pan/filter and other components are definitely going to be replaced as part of the service, then the pump inlet method is a good choice if you are prepared for dealing with the added mess. An effort should also be made to make the supply hose as short as possible between the fluid supply container and the pump inlet since the pump will inhale any air in the hose before it is able to draw fluid up the hose. If you can pressurize the supply fluid or prime the supply hose that might mitigate this potentially large air intake by the pump.

Intermixing during an engine oil change is not much different. When the oil is drained from the pan drain plug, plenty of old oil remains on top of the cylinder head, in various areas of the engine, on the outlet side of the oil pump, and in the oil cooler. This old residual oil mixes with the new oil, causing the new oil to be immediately discolored. No big deal. The only way to remove all of the old fluid from a transmission or engine is to remove it from the vehicle, completely disassemble it, and clean all the old fluid off of every single component (see jackra_1's rebuild thread!).

Millions of transmissions have survived hundreds of thousands of miles each with their fluid being changed only by the drain and fill method. The cooler line flush method offers the advantages of a more complete fluid exchange in less time, and may be the preferred option under many circumstances. But it is always prudent to think ahead about what one is trying to achieve so the best method can be selected before work begins.

Cheers,

Don

 

I don't like to use percentages even though I studied Applied Mathematics. But let's estimate.
Replacing the filter only will result in about 60-65% fresh fluid.
Further removing the valve body will give us about 75% fluid exchange. But probably more important it gives the opportunity to replace the seals, especially the square one which is not expensive but it is so important and may fix the problems the tranny exhibits.
Any additional flush is bonus but I believe it should be done with fluid returning to the transmission under pressure and should not require more than 4-6 litres extra if the fluid in the pan is new. Shops use the cooler lines method because it is quick and easy on most cars if you can intercept a cooling line which should be the return from the cooler. It is also safe if it uses the trans pump since it has the required return pressure for lubrication. But I believe it is only effective, without a lot of mixing when only the Torque converter is flushed and not the inside of the transmission. I will explain.

On a trans that works and only needs fresh fluid, filter and seals the goal is to replace as much fluid as possible with the least amount of mixing. What I am arguing is that replacing as much fluid as possible in the pan will get you closer to achieve that goal. Once the fluid is sucked from the bottom of the pan, more fluid is returning to the pan at cold idle than going to the cooling/lubrication. So there is a lot of mixing in the trans pan from the pressure relief valves, valve body valves and clutch packs, more than what's coming back from the cooler especially with cold fluid. So IF most/almost-all of the fluid is fresh in the pan than most/almost-all of the fluid inside the trans would stay clean, recirculating and mixing only with clean fluid returning from the cooler when flushing. So in this case virtually no mixing except in the Torque converter.

So a flush with almost no mixing inside of the transmission is possible with cooling lines flush procedure. But only if the fluid in the trans is replaced first and then the converter is flushed so I would rename the trans flush to a converter flush using the cooling circuit. And please find a way to have pressurised fluid to the cooler return/lubrication circuit.
Of course we would not discus about flushing if there would be a drain plug on the converter like Mercedes has.
Therefore the advantages of no pan/pump inlet flush are:
1. Minimal disassembly with only the oil pan removal
2. One step flush of the Torque converter and cooling system
3. Wash/ rinse of clutch packs and, most important, the valve body internals
While the first 2 can be done using the cooler lines flush, washing the valve body and clutch packs is not done so that would be the principal advantage.

On a trans that has issues the only thing I would do before taking things apart is check and adjust fluid level to see how much is missing and if things improve. This step is mandatory when trying to solve issues. I would then drive the car and collect data of solenoids operation and adaptations. Than reset adaptations and see what changes before moving on to fluid replacement. Then I would still drain and replace the square seal and tube seals in Jag's and BMW's cases. It is the least amount of work and disassembly that would give me the opportunity to have a "conversation" with the transmission to see what may be wrong before spending more money. Fluid colour, debris, magnetic particles and most common leaking seals can tell me what is the next step: R&R or fresh fluid by also doing a converter flush. Even if the defect is not obvious I would install a new filter, refill the trans and flush the converter to see if the problem gets solved or behaviour improves. Less money than R&R and some chances to free up possible sticking valves. Plus, if it works, everything stays put. And if it doesn't solve the problems the fluid and pan/filter can be reused on the repaired/replaced transmission.

But no matter what method is used the new fluid will have particles in suspension and will not be perfectly clean because debris stay in nooks and crannies so perfect washing is not possible.

 

you know, leaving a quart or two of dirty fluid in the trans isnt going to hurt you. you guys are making way too much of this issue. And if youre not careful you might cause a problem if you suck in air or have a line fly opff with these makeshift flushing rigs.

Empty the oil & put new in and youre good. If you want to be **** about it, do it again a few weeks later and youre going be fine. When you change your engine oil theres so much old oil in the oil pump, passages, lifters and lines but you cant tell when you look at the dipstick after an oil change so change it and move on! or change it again!

 

The reason I moved from the gravity fill method to the pressure fill method is that there is no suction at the cooler line inlet port. The only way air could be sucked into the transmission would be if the pan were allowed to go empty, which is why I advocate doing the flush 1 liter at a time, replacing each liter of fluid removed with a liter of fresh fluid.

I have now serviced more than a dozen 6HP26s and the makeshift flushing rig has never yet leaked or had a "line fly off." I keep thinking I should invest in the "official" flush fittings that DGL ordered, but the makeshift rig works so well I keep putting off the purchase.

Cheers,

Don

 

Well, well, well, I received the extra 5 liters of fluid to complete the fluid change and pumped in about 1.5 liters more than I calculated I removed. In total I've used 18 liters. I originally bought 13 and wasted 2.3. Then I bought another 5 to complete the change. I measured the fluid removed, plus 2.3 liters I wasted fixing a pan leak, and added 1 more liter for shrinkage; then, I pumped in another 1.5 liters so I would not have to pump in any more fluid through the fill plug over a hot exhaust pipe. The wasted fluid fixing the pan was measured to be 2.3 removed and 2.3 added to replace it.

I was happy to be almost done with this until the final fluid level check procedure. I pumped in the extra 1.5 liters to make the final fluid level check easier. I started the car and did all of the other fun stuff. When the transmission pan and casing reached 35% I opened the stupid fill plug to let the excess fluid drain out. Well, no fluid drained out. Consequently, I did not over fill the transmission enough with the 1.5 liters I calculated as extra. Now it gets real stupid. I stopped the engine to let it cool a bit. Then I started to wonder how much I was short and needed to pump in. So, I thought I would check by slowly removing the fill plug to see if any fluid would come out. I thought I could slowing unscrew the plug until it started to drain slowing and quickly screw it back in without completely removing it. I was on the last thread and no fluid coming out. I slowly screwed in out 1/2 turn and the plug fell out with the pressure of the fluid. Here I am on my back under the transmission trying to put the fill screw back in with fluid spilling all over me. Yup, I took a bath in Jaguar transmission fluid. I would say about a full litre. Damn, that stuff is tough to get off. I had to take 2 showers and stunk up the house and my garage stinks of Jaguar transmission fluid.

Now what do I do. I don't want to pump in fluid through the fill plug over a hot exhaust pipe. Should I remove the cooler lines again and pump in about 3 liters through the cooler return line and hope that is enough before attempting the fluid level check procedure again? Would I need more than 3 liters? This has to be one the most stupid things I've done. Why would anyone build a transmission so difficult too service?

 

If your Jaguar trans set up is the same as the XJ8's the exhaust pipe can easily be avoided.

 

On some cars the exhaust sits closer to the transmission fill plug than on others. I haven't kept track as to whether this varies by model or just different cars of the same model. On some cars the exhaust is just a couple of inches away from the fill plug, which is why an Allen key has to be ground short to even be able to remove the plug, and getting the plug threaded in and out with fingers is very difficult without touching the hot exhaust. DGL must be dealing with one of those close setups.

 

Yes, I had to make a stubby allan key. it is very tight and the hot exhaust is a bitch.

 

There's not a lot of room on either of mine.
Been done on jack stands, as well as a lift, without burning myself.
Lift made things a LOT easier to do, with more room to work.

 

How many liters are required to fill from a state where the fluid is only filled to the fill plug when the engine is off. I have the 6hp28.

 

I pumped in 1.5 liters with some waste from the smooth drip. Did it through the fill plug following recommended ZF procedure. Where I lost about .5 to 1 liter after opening fill plug with engine off after doing a fluid change through the cooler IN/OUT transmission ports I was only .5 to 1 liter short, so close. I measured all the fluid removed, wasted, and pumped back in and added a bit more hoping to end up a bit over after doing the fluid change through the cooler IN/OUT transmission ports so I would only need to drain a bit out, but I was short .5 to 1 liter. All done now with most other fluids changed, e-diff, engine oil, brake fluid, and coolant--all Jaguar branded fluids. Getting ready for the spring.

 

It was no problem to push the tab back into place. With the trans weight removed it was a straight shot to push the connector back in and twist the locking ring home. everything is back together and working fine.

 

Does this process apply to a 2007 XKR? In other words does the 07 XKR have the 6HP26 trans? Mine is leaking somewhere above the rear trans cross member pretty good. Just started during winter storage.
Thanks.

 

Oh by the way, I have been member of forum but my account keeps disappearing? 2nd time I’ve had to rejoin?

 

Yes it is the same 6HP26 transmission. There are differences from model to model and year to year but they relate to electronics, solenoids, and the mechatronics unit.

Not the fluid volume.

 

Thanks, jackra! Printing thread and will start rounding up parts. Where is a good outlet for the pan, pan gasket, electrical connection, in USA?

 

I bought mine on Ebay from a trusted seller.

I purchased everything as a "kit".

In the past I used LF6 trans fluid however I am now going to use Mercon SP.

 

Probably the mechatronic seal but also could be the transmission mount leaking oil onto the cross member mimicking a trans leak.

Mine was - need to replace it this weekend.