5hp24 intermittently not changing gear

[gussy]

Hello everyone. Wondering if anyone else has had a similar experience with their Bmw v8 range rovers ~265,000km

A few months ago, I was driving home from Perth in a 60 zone, when strangely, taking off from the lights it would only have first and second gears. Turning the car off and on again at the next set of lights it was all good again for another few minutes and then back to only one and two.

I drove straight to my mechanic and he plugged in the testbook- no fault codes thrown. Took it for a test drive and it was perfect. I drove home - and it happened again. Went back to the mechanic. Still no codes. Still perfect on test drive. I left him with it and he used it as his personal car for a week and there were no issues. As a precaution, he did a full fluid flush and changed the filter for me (genuine Bmw oil etc). Apparently the oil was in pretty bad condition, lending me to believe the transmission has never been serviced.

Fast forward another month and I was driving out to Kalgoorlie from Perth, coming up the hill which is 80km/h and very long as western Australians will know, and near the top it wouldn’t go above third (this is after about 10km Of climb in 3 & 4). Turned around and went back down the hill because I didn’t want to break down. It was perfect by the bottom of the hill. Decided to go back up again and it happened again near the top. Interesting. Pulled over - restarted the car and all good. Did the 1400km return journey to the motor bike race dad was in at lake perkolilli with no issues.

Two weeks later & It’s happened once more randomly this weekend - won’t go above third and hesitates to drop gears when decelerating. Restarted. Totally fine. I drive about 400km a week for the commute and it’s never bothered me.

Just wondering what peoples thoughts are before I take it back to the mechanic next week. The fact that it’s not slipping or losing drive or going into limp mode (third only) is puzzling. Could it be an electronic/ TCU issue?

Cheers.

[FisherX]

Sounds like your transmission is going into over temp mode and employing it's cooling strategy. If the tranny reaches 140 deg C the cooling strategy will become active until it cools to 130 deg C.

When this happens the gearbox will remain in lower gears to reduce the load on the box. When it happened to me I was towing a 3t trailer that was going great on the highway but went into over temp mode after driving through a town. I didn't get any fault codes or warnings when it happened but it wouldn't go higher 3rd gear at 100km p/h until it cooled back down.

So I'm thinking your problem is in your cooling system. Maybe a blocked or faulty gearbox cooler.

I've heard that the radiators on our models can get sludge built up in the bottom that can restrict the flow through the cooler, but their is also a thermostatic valve in the cooler that could be an issue.

[p38arover]

I had it happen to mine the day after I bought it.

It was a blocked transmission oil cooler.

See Oil Cooler Gearbox / Transmission L322 4.4 V8 Petrol ZF Steptronic (OEM) PFD0000 Island 4x4 - Specialists in Land Rover and Range Rover Parts and accessories for all models. UK and worldwide mail order. (https://www.island-4x4.co.uk/cooler-gearbox-transmission-l322-petrol-steptronic-hella-pfd000020-8mo376756781-p-7596.html)

[landie56]

Hey,
I have a similar problem, but failed to select any gear.
From that point l had to have a full gearbox rebuilt and cooling system flush and it is like driving a new car off the car lot.
Mine was 5l40e gearbox for TD6.

See photo of what happens to gearbox pressure plates rubbed to fine metal slush.

Cheers Rangie2002 https://uploads.tapatalk-cdn.com/20191001/ed8fb7d656adf93dcfa7758adb4ff0c8.jpg

[gussy]

Thanks for the input gents! Interestingly I had the same happen to me p38rover - transmission oil cooler was faulty a few days after I bought it in Melbourne just under a year ago. The dealer had it replaced and it has been perfect ever since. Across the Nullarbor and another 20,000km later - including some pretty hairy off-road trips.

FisherX, perhaps it’s the radiator on its last legs. I’ve noticed it has a slow leak along one of the seams near the bottom. Maybe it’s decomposing - filling up the bottom rows and leading to insufficient cooling under strange loads. Something I’ve been meaning to get fixed at my next service.

I’ll get the radiator replaced and report back. Do they need to flush the coolant side of the cooler to remove any potential debris? I’m hoping it’s just that. Not keen for your experience landie56!

[p38arover]

Replacing the radiator is relatively easy. I did mine as it was leaking. Check your reservoir pressure cap and make sure it reads 140 underneath, not 200 (kPa). I suspect 200 kPa caps cause over-pressurising of the radiator causing leaks from seams.

See Expansion Tank (radiator cap) part #PCD000070. Use genuine Land Rover parts only. (https://www.aulro.com/afvb/l322-range-rover/206748-expansion-tank-radiator-cap-part-pcd000070-use-genuine-land-rover-parts-only.html)

I made up this water pump restraining tool so I could loosen it. The drawing was on FullFatRR.com

https://www.aulro.com/afvb/attachments/discovery-2-a/131177d1508582515-viscous-fan-removal-tool-story-pictures-spanner.jpg

See also:


https://www.youtube.com/watch?v=9aT3NYUnjMU


https://www.youtube.com/watch?v=KV-klGMnuCs

[FisherX]

There was a test to see if the lower bit of the radiator was blocked. I can't find it atm, but it was pretty easy and I think all you had to do was open the drain cock on the radiator and measure how much drained out in a minute. Might have been 2 litres in a minute.

My radiator was changed in 2016 apparently, but I wouldn't trust the workshop that used to work on the car. (they charged the previous owner $ 980 to reset the "suspension inactive" fault after they change the battery [tonguewink]. And that was above the $760 they charged for the battery)

But yeah if your car has 265K on it and it hasn't had a radiator it's probably due.

[gussy]

So this issue might have to wait a few weeks now. Yesterday a timing chain guide went on the way home from work. Everything is letting go!

Time for some weekend tinkering on that - and the radiator at the same time.

[Laurie]

Timing chain guides failing is a very common problem on the BMW and Jaguar V8 petrol motors. There's plenty of videos on doing the repair, and checking the VANOS while in there. In the end it comes down to cost, if you can do it your self it's very worthwhile, getting it done in a shop will be expensive.

Laurie

[gussy]

There was a test to see if the lower bit of the radiator was blocked. I can't find it atm, but it was pretty easy and I think all you had to do was open the drain cock on the radiator and measure how much drained out in a minute. Might have been 2 litres in a minute.

My radiator was changed in 2016 apparently, but I wouldn't trust the workshop that used to work on the car. (they charged the previous owner $ 980 to reset the "suspension inactive" fault after they change the battery [tonguewink]. And that was above the $760 they charged for the battery)

But yeah if your car has 265K on it and it hasn't had a radiator it's probably due.

Just replaced the radiator after all my timing chain replacement fun. Let’s hope it solves my problems. The flow rate from the old one was a drip [emoji98] rather than a stream so I’d say the bottom section was definitely blocked!

[gussy]

Gear change problems solved with the radiator replacement [emoji1362]