So the neurotic paranoid person I am with unknown vehicles had such a freak out over every unknown sound on my trip. First I was sure the TC droning was back as soon as I hit the highway. Then it seemed to change in tone. Then it changed in tempo. Then it was irregular. Yet we were still moving and no warning lights. As I tuned my ear to every subtle unfamiliar sound I started to remember that this has new tires and won't sound like my other cars. Also wind! It makes sound and different sounds at different speeds. Eventually I figured it out and now about 700 miles I still haven't heard the sound I heard before the fluid change. I hope to do the next 5 liters this week and I will pay close attention to fluid temp. I have one questions. Does the overflow need to stop dripping before plugging or just become a small fine line of dribble?

Small fine dribble.
Driving in sport mode limits top gear lock up.
ZF boxes are the best box in the world no questions asked, dont panic, they absolutely very rarely ever fail in an instant.
You are doing good by your box.
Trans fluid burns when it gets hot it reduces its effective life dramatically this is why its full synth in this box normal operating temp is pretty high, your cooling system needs to be in top order.
If you tow a lot get a bigger trans cooler.
My ZF in my P38 the fluid is regular ATF if it gets up to 120c its effective life is reduced to 5000km.
Changing the fluid and keeping your cooling system in tip top order is a priority do this and your FF or P38 will be as reliable as a Toyota.......but better.

Yes thanks. I'm going to play with my thermal reader tomorrow. I do believe the horror stories about RR is because of dealer costs and lack of the critical maintenance.

OK the occasional brainfart engineering mistake too like tilt and telescopic steering wheel.

Last week end I was on a dirt track 50km from help.
Came across a broken down Volvo AWD soft roader.
Professional looking type driving it, it was about to snow.
Brand new car just stops (diesel) looked like the fuel pump had died to me. Gave him a lift to phone reception and help.
An L322 has great capability, potentially but is a bit soft underneath.......give me a P38 any day off road.
Yes you are dead right about maintenance, most people actually cant afford to run an L322 or a P38 for that matter, they need a lot of up keep and $$$$s.
If you can do most of the work for your self they are great trucks and will be seriously reliable.
All modern cars are crap really.....if you want to get out in the bush and bash the thing up a bit.
Best car for comfort and reliability and potential for modification is a TDI Discovery.
My L322 is a magnificent bit of kit that I can mostly tame, but if I want to take on some tracks and do some adventuring the P38 leaves it for dead.
Happy days

RRPhil wrote:

Although it’s good to hear that your fluid refresh has stopped the torque converter lock-up clutch shudder I suspect this will only be temporary. I should start saving up to have your TC removed, re-manufactured and replaced if I were you (approx. £250 + 5 hours labour + filter + fluid). Worn LUC issues most commonly occur soon after 100k miles has been clocked up for the 5HP24 in the Range Rover. It will be interesting to see how long it takes for the cattle-grid noise to return.

Even then you may be able to mask the issue with a fluid friction modifier (Dr. Tranny, etc.) as a further temporary measure but, the fact is, the LUC is worn and ultimately will need replacing.

Phil

What sort of temps did you see with your IR reader?
My P38 with the 4HP24 would give me a 60-65c reading at the pan in 35c weather.
Cant say I have checked out my L322....will do and revert.

I believe before my first flush it was high in the 120c range. I had to drive about 45 min with a fair elevation climb. I dismissed the temp reading as error because the IR reader was new and I assumed the fill temp was normal operating temp. Recently after a normal warm up temp read about 90c at the front of the pan and about 82 the rear of pan. I will compare the IR reader with iidtool readings and do a correlation.

120c is smoking hot. Hopefully that is incorrect.
When I get my FF out I will do a check on my pan, could be a day or two.

One would hope the trans runs a little cooler than the engine.

Looking at the workshop manual;

"thermostat regulates the coolant temperature in the range 80°C to 103°C."

"Should the coolant temperature exceed 113°C the electrically heated thermostat is activated independently of the prevailing engine parameters."

"Should the heated thermostat fail, (fault codes will be stored in the ECM) the EMS will ensure the safe operation of the engine and the thermostat will operate as a conventional unit."

Transmission;

"The fluid cooler has a thermostatic valve which is opened by transmission fluid temperature. The thermostatic valve is opened at a transmission fluid temperature of 80°C (176°F) and allows engine coolant to flow through the fluid cooler."

The GM trans behind the diesel (tractor engine) operates at 91c-95c via thermostat control, there is no mention of such defined control for the ZF box that I can see.

I'm sure it wasn't that hot. I had been switching between F and c. Pretty sure I saw 175F then at one point. Since then I don't recall seeing over 90c at the front pan.

UPDATE: so nice to have the BT iidtool. I drained the transmission pan for a second time n 3k miles. I will post a picture of the mud milk chocolate colored fluid later. The first fill took 5 litres. So far the second fill has only taken 3. I'm letting the transmission cool a small bit and recheck. The iidtool was reading 41c while the IR reader off the pan was reading between 27c and 33c depending if reading taken off the front or rear of pan. I must assume the transmission temp sensor is correct and it went from 37c to 41c in about 5 min. It was holding 41c for a couple of minutes and probably would have stayed there a while longer but I want to do this by the book even though I can't imagine 1 degree would make any significant or measurable difference.

If your fluid, is mud milk colour, you could possibly have a coolant bleed. Ie, you water is mixing with trans fluid. Via a porous radiator.

I stand corrected. Upon better light of the day the fluid is a good dark brown. Not quite as black as the picture shows. Smells very much like the new oil. No discernible particles either. I'm "assuming " the detergent affect of the last drain and fill is working well. Since I can get the oil for $10/liter and I started with 11 liters I'm going to drain and fill a couple more time in the next couple thousand miles. I'd like to see near new looking oil drain out at some point and see what changes with the torque converter and shift points.
OK just finished with 2.8 liters out and 4 liters in. As I monitored the temp and filled I stopped filling at 4 liters and 33c on the iidtool to shift through the gears. That took about 2 min. When I went to continue filling the very slow drip had become a very fast drip. The temp had gone up to 34c. As the temp climbed to 35c the drip became a drizzle. I didn't add anymore. Upon test drive there was a slight momentary torque converter rumble at the usual 5th gear low rpm range but disappeared quickly.
There are no leaks to account for the drain and fill difference so I must assume the last fill was too hot and gave a false reading or possibly a clogged port maybe. I will see at the next drain and fill.

That fluid doesnt look perfect but not as bad as I have seen it.
The sniff test is not really scientific but it gives an indication that the fluid isnt Kaput.
Good work Doclees, its a bit of a getting under there and filling isnt it.

Not so bad these days with the iidtool. The normal off road height was just about 1 inch too low. So with a tweak of the iidtool I have my needed clearance. If I do the drain and fill in the morning I can finish before the exhaust gets too hot to bump into.

Ok sorry been a while getting back about the temp.
After a reasonable drive I get 76-80c around the the pan and 96c on the trans cooler line at bottom fwd end of bellhousing.
This is with an air temp of 25c.
Some extra heat shielding wouldnt hurt on the CATs as they are showing 180c and are not very far from the trans pan, radiant heat would be adding to the cooling systems load.