So after dealing with an RPM fluctuation for a few thousand miles I decided to try a transmission fluid change. The original fluid had been in since new as I recently got the vehicle at 123k.

I followed the procedure for a normal drain and fill. I got out approx 3L of foul smelling dark fluid and the 3L of fresh didn't make a difference on the RPM fluctuation.

I wasn't happy with the dilution and wanted a full exchange. Also wanted a new filter. Some have gone with a metal pan with replacement filter but I chose to replace the original ZF pan with another with built in filter. I then proceeded to completely exchange my fluid and I'm happy to report that the RPM fluctuation is gone!

I'll share my set up for the exchange below.

 

Materials:
1) 10ft 1/2 inch inside diameter hose cut in half
2) two hose clamps
3) container with markings by the litter
4) large funnel
5) m18 1.5 fitting with hose barbs
6) 11-12L of clean fluid

 

1. Get the vehicle level
2. Drain what you can from the pan and replace drain plug. (Not needed if pan just changed as in my case)
3. Disconnect the passenger side transmission cooler outlet infront of the front axle and slide on one hose and clamp tight. Put the other end in the container and tape down so the pressure doesn't throw it around. (May need to drop skid plate, mine was already off)
4. Remove fill plug and thread in the fitting then attach the other hose and clamp tight. Attach funnel to the other end and fasten up high on something.
5. Refill with same amount that you drained out earlier from the pan.
6. Have a helper start engine and run through the gears while you refill with the amount that is coming out from the transmission cooler. (May need to stop engine if you can't keep up with the fill)

 

7. Once coming out clean or you run out of fresh fluid (hold 1-2L back, to top off later) you can reconnect the cooler line up front.
8. Now fill till fluid runs back out the fill tube. This is easy and clean with the fitting threaded in and hose connected since all you need to do is lower the hose into a clean container and if full the fluid will come back out the hose.
9. Lift hose/funnel back up and run engine. Repeat number 8 now while engine running up to temp (look elsewhere for the temperature, I just estimated).
10. Leave engine running and thread out the hose and fitting. Wear gloves, that exhaust is hot!
11. Replace fill plug
12. Shut off engine
13. Feel good knowing you didn't just dilute the garbage that was in there

 

There's a good discussion on this process here: https://www.disco3.co.uk/forum/robbi...ge-141425.html

It's on my list of jobs over Christmas.

 

This is a great writeup and I have acquired all the parts, supplies, and fluid. You mentioned replacing the pan/filter as well. I am assuming you dropped the pan, drained the 3 liters or so, installed the new pan and then continued on to the flush procedure as documented. Can you confirm that is the process you followed to install pan/filter and do a full flush?

A local independent shop I have come to trust and often buy parts and fluids from told me not to do this procedure. They told me all new fluid could exaggerate the issue with the torque converter and have it slipping. They also told me I have to loosen the trans mount, remove a crossmember and jack the drivetrain up to get the pan out, yet nobody else indicates that. Many writeups indicate that you drop, twist, tilt, twist and remove to get the pan out. Illustrated here: . I have found many posts across many forums stating that they did two fluid drains and fills and the RPM problem went away. I was thinking your process here cuts to the chase and does not require two drain and fill operations and that all new fluid has to be a good thing. This shop now has me paranoid. Are you still running with no RPM fluctuation?

Thanks in advance for any response,

 

The process you describe is how I’ve performed the work on my jags. (same transmission).
Many comment that new fluid will exaggerate poor performance issues. There is another perspective: The issues are already in place and the old fluid is not only masking the problem, but causing further aggressive wear.
You never heard of a F1 car team not replacing the fluids, have you?

JLR had finally changed their stance on the necessary maintenance of the transmission. It was past due as it completely conflicted with the ZF recommendation.

Anyhow, I know nothing of your vehicle but I can tell you that at 160,000 km, I have had the transmission, differentials and PTU changed twice. (ditto schedule for the jags). I have no issues with slipping, clunks, shifting, whirr sounds, etc. And I drive my vehicles hard, thus the more frequent, all encompassing, maintenance schedule.

Cheers!

 

The pan situation is slightly annoying if you haven't already found out. Basically the filter is built into the pan and has a tall plastic pipe that sticks up to enter the bottom of the transmission. In order to remove it easily you have to be able to drop the pan straight down but the cross member is in the way.

There's basically 2 options for removal.

1. Drop the pan slightly then use a thin hacksaw blade to go in and cut the plastic pipe through the crack and then remove things easily.
2. Loosen the engine mounts and jack the engine/transmission up to allow you to wiggle the pan out. ( I did it this way, but be careful when jacking the engine up that you don't break engine harness/coolant pipes/other things connected)

Then options for reinstalling.
1. Reinstalling a new OEM PAN is again difficult because of that pipe sticking up. I managed it with the engine jacked up and wiggling it in.
2. An easier way would be to buy a new two piece PAN so that the filter with the tall pipe installs separately from the PAN, then the close quarters issue is in a big deal.

 

Regarding a final solution for the RPM fluctuation, All new fluid did improve things for a couple of months. Ultimately however I still saw some fluctuation and I posted my solution in a different thread. In short, I got a ZIP kit and rebuilt the valve body with new solenoids as well. That process did resolve the RPM fluctuation permanently

 

Between this thread and a similar thread here :https://www.landroverworld.org/threa...results.42141/ I ended up ordering all parts to do the Zip kit, solenoids, and the pan/filter.

I have a question, if you were going to do all of this at once would you do the flush first? I’m thinking I should flush, but not fill, then drop the pan, do the zip kit and fill? I’m thinking I’ll waist a bit of fluid but this would help ensure I’m pushing clean fluid into the updated valve body as bd not pushing a bunch of junk into the new filter right away.