Does anyone know offhand which line at the radiator trans cooler is supply vs return? I need to disconnect the supply line to the cooler in order to pump out and replace the trans fluid. Thanks.

 

This is from SNG Barratt's parts catalogue. Item 1 (oil cooler return line) appears to be the upper line on the radiator and transmission housing. I assume this refers to trans oil returning from the trans to the cooler, and that this is the one I want to access. Item 2 (oil cooler output pipe) returns the fluid to the trans. Let me know if there are other thoughts.

 

The lower line coming from the transmission is the supply line. The line that goes into the top of the transmission is the return line from the cooler.

 

It should be the other way around: the line connected to the top of the transmission is the ATF delivery to the cooler. This line, if disconnected from the cooler, can be used to attach a hose to it to flush the fluid. Alternatively, the line connected to the bottom (side) of the transmission (return of fluid from the cooler) can be disconnected from the transmission and a hose connected to the line at this point could be used for flushing (see the attached extract from the 722.6 WIS, by Daimler AG).

Jaguar Workshop Manual:

 

Thanks - that was my take. The line at the cooler looks like the easiest to access so we'll go from there.

 

Hi Doug,
Actually, today I started working on my X308: Dumped engine oil, ATF, coolant, removed radiator WITHOUT removing A/C radiator, removed already the bolt from the balancer and now I am fighting with the balancer - it is resisting the puller. The goal is to swap the timing chains and tensioners.

I am fairly sure the UPPER line is the supply line. Even though I just removed upper and lower (to be able to remove the radiator) I have not confirmed, which is which, but I think it is always the upper. It was the upper line on my Ford Fairlane NL '97, and it was like that on my S-Type '04, which I just fixed.

Good idea to do a full ATF flush rather than just removing the contents of the sump and refill it.
You will probably find some useful hints in my S-Type threat regarding full flush:
https://www.jaguarforums.com/forum/s...s-type-264102/

The X308 has a 5 speed ZF transmission: 5hp24.
I am just trying to find an answer, if ZF Lifeguard 5 is the only option for 5hp24. (note: Multi vehicle ATFs are no option for the S-Type ZF 6hp26, and probably also not for the 5hp24.) I am starting a new threat with that question...

PS: CAUTION! Don't take the upper-most pipe mistakenly for the upper ATF pipe, because the upper-most pipe is the A/C-pipe containing the aircon-gas R134a. Do not open/remove that pipe! It goes to the A/C radiator in front of the coolant/ATF radiator.

 

Gosh, sorry for misremembering. A while back I was chasing down a shifting issue, and I disconnected a line to measure flow rate. But now I remember, I was concerned that I had a blockage in the cooler, so although I did disconnect the lower line, it was so I could measure flow coming out of the cooler when I started the car, not so I could measure flow coming out of the lower line. That means that the top line is the supply side. I should have spent a minute to remember better!

 

Some time ago on one of my BMW-s, because I was not sure where the fluid would come out from, I attached hoses (with some adapters I made) to both sides of the top cooler connection and put both into the bucket. Better to be safe than oily!

 

Looks like the 722.6 WIS extract that I attached to my post #4 has disappeared (or I forgot to attach it?). Here it is again.

 

The 722.6 also had a drain plug on the torque converter which may have been omitted from certain year (2000 or 2001 ?). My 1999 transmission has it:

 

MS, many thanks for posting the flush procedure. With my drivetrain stuffed into a Mark 2 it's impossible to access the banjo location they use, so we'll go with the cooler end. I thought I was all set with 10 liters of Pentosin 134 but I see the procedure calls for 14 so will have to order another jug. I also note the trans should be at operating temp which I wasn't sure about. And yes, my '01 does not have a drain plug on the converter - wonder why they did away with it?!
Aquifer all is forgiven - I think we've all given our best advice here only to be corrected at some point. I feel lucky for having so many folks take an interest in helping.
And Peter thanks for the heads up on the AC line. I've got a one-off aluminum radiator with only the original trans heat exchanger installed so no chance for a mistake.

 

Well, the upper-most line, which I mentioned, is not actually going into the normal radiator, but bypassing it to the other radiator in front of it. But that is easily overlooked and the upper-most A/C pipe could be mistaken for the upper ATF pipe.
Yes, for my '04 S-Type I needed about 14L for the full flush.
About temperature: It is better to even release the ATF at 40°C, but in my case that was not possible, as the engine oil was out already.
But the filling procedure on the S-Type is definitely 40°C ATF temperature AND: It is deemed to be be full, when the ATF comes flowing out of the filler plug WHILE the engine is running (engine running or not makes a difference of about 2L). I very much assume that is the same for the X308.

 

What a mess! Aquifer - it turns out your memory was spot on, and unfortunately I learned that the hard way. In the diagram posted by MS above the fluid is circulating clockwise - out the lower line on the transmission, up through the cooler and back into the trans through the upper line. Per SNGs parts diagram the upper "oil cooler return pipe" refers to oil returning to the trans from the cooler and not oil returning to the cooler. Similarly the lower "oil cooler output pipe" refers to oil leaving the trans to the cooler and not leaving the cooler.

Having unfortunately disconnected the upper cooler line I of course had no discharge into my neat little bucket setup but a massive flow of hot trans fluid out of the upper cooler port. Adding insult to injury the beast had been run to get everything up to operating temp, so of course the fans kicked in and flung fluid everywhere. On a positive note the flushing procedure provided by MS worked perfectly, and the trans internals were remarkably clean. After 20k miles since the last fluid/filter change the bottom of the pan was spotless, with only a trace of friction material clinging to the bottom of the filter housing. The purpose of this flush was to replace an incorrect fluid, so hopefully no damage was done. Now it's off the the store for more Brakleen!

 

Ups. Sorry. That was unexpected. So lesson learned: We cannot conclude from one car to another.

Actually I came across another case, where this rule applies: On power-steering it is normally (Fairlane and other cars) the upper line, which returns the fluid to the reservoir, but not so on the X-Type, where it is the lower, because of the internal design of the reservoir.

So when I do my XJ8 ATF flush, I will still have both pipes off with hoses connected to both, and see, which one wins...

 

As a general rule..the fluid coming from the transmission will be hotter than the fluid flowing back unto it.
An infrared thermometer can measure the heat coming from the two lines thus determining the flow direction.