L322 Trans Failsafe Prog - Gearbox Issue

I wonder if anyone can help with an issue I'm having with my 2004 L322 Vogue 4.4 V8. 124k miles

I have searched the forum and found lots of threads about the trans failsafe prog, all with slightly different issues. Can anyone help with mine specifically?

I seem to have an intermittent gearbox issue.

- Sometimes it's completely fine and works as it should.

- Sometimes it works without displaying any error messages but seems to occasionally do a jerky gear change with a clunking noise, particularly when moving off from stationary or something strange like when accelerating and it should kickdown, it changes up instead of down and jerks.

- Sometimes when putting in manual mode, it refuses to change when you tell it to and simply flashes the gear you are trying to select then goes back to what it was in before, and doesn't change gear

- I have had the trans failsafe error come up a couple of times, and it go into crawl mode. The first time was when I had the car in sport mode. Second time, it was in auto and I was pulling off from a roundabout, accompanied by a clunking noise

- I have also had one occasion where the engine management light came on along with the trans failsafe error

Any suggestions on the likely cause?

- Check trans fluid?
- Get proper trans fault codes read by dealer?
- Transfer box?
- Gearbox failure?

Thanks in advance
James

get your battery tested

Start with the simple things. BATTERY VOLTAGE as per Overlandrover, then oil level. Note to check oil level, when engine is running and gearbox is a t30c -( please check, memory is fuzzy on this)

Just checked battery. 14.5V at tickover, 12.7V engine off. Seems normal.

Check transmission fluid next then? that will be a job for Saturday

I would always look to get some diagnostics before paying somebody a fortune to read faults for you. I would buy an allcomms as I have the same vehicle, same age and 120K miles and my allcomms paid for itself within a few months of owning it

Do you know anywhere that sells one? Nothing on eBay and a quick Google only comes up with US sources

Allcomms is designed and built by Richard storey Wilson, RSW and sold by him in the states and his service and backup/help is very good, unless you can find one second hand you have to go to him but well worth it against sending you motor in to the stealers.

i got mine from the US, gets across the USA really quick until parcelfarce get their hands on it... well worth the wait though

Anyone else got any ideas on what it could be in the meantime?