2004 TD6, gearbox was re-built 15 months ago, no problems for 12 months until i put the caravan on, after 1 mile 'clunk' - Trans Fail, just as i was starting from standstill in traffic, i pulled over and 'phoned a friend' who suggested cycling the ignition, this reset the problem and we continued on our way until we met with a few hills and it did it again several times so had to pull over and get recovered home (4 hours later!, kids not impressed!), tried to drive it next day and it was ok all week until i stopped for fuel, when i tried to drive away it felt like 'clutch slip'- engine revving but 10% drive, then 'clunk' -Trans Fail, i cycled the ignition again and all was well for another week then it did it again, this time i noticed the temp gauge was reading 50%- i found that it only happened on warm days when the cab heating was selected to 'off' and if the engine was switched off briefly, it was ok if left to cool down for 1/2 hour or so, i diagnosed that the viscous fan wasn't doing anything and replaced it, this has helped but it's still doing it, i can drive it all day no problem until i stop for 5 mins so it seems like it must be heat soaking back to the box somehow???
What i don't understand is why it doesn't throw up 'transmission overheat' before going into 'Trans fail'
RRPhil?

What next??? Trans cooler???

I've just had to shell out £600 for turbo rebuild too but at least it's running ok now. I'll have to say that i'm reasonably surprised now if i actually finish my journey without having to call Greenflag...

Thanks,

John.

I imagine it's not getting hot enough for trans overheat message... sounds to me like the box has had it, pulling the tintent was the last straw...

Get a diagnostic tool and see from the live values how hot the gearbox is...  Pete

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2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

I checked the feed/return pipes to the oil cooler from the gearbox tonight after driving home 12 miles, approx 45C lower pipe, 55C upper pipe and 80C sump. Whilst i was under the car it decided to wash/wipe the headlights all by itself!!! Jinxed?

That's pretty cold, trans overheat come in somewhere near 120deg.... Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

As we’ve discussed many times on here, the 5L40-E transmission generally lasts between 80k and 100k miles in the L322 before the valve blocks (which GM decided to make out of cheese) wear to the extent that the spools leak and cross-talk and the resulting loss of hydraulic pressure allows the clutches – and particularly the torque converter lock-up clutch – to slip. Eventually the friction plates wear through to their backing plates, and beyond, generating huge quantities of metallic debris in the process.

The transmissions then get sent to a cowboy outfit who pull the transmission apart, clean out the swarf, replace the torque converter and then sell it back into the marketplace as ‘reconditioned’. Of course they’ve just treated the symptoms (the failed converter) and not the root cause (the worn valve block) but they hope the transmission will last just long enough to get through its warranty period and then they’re in the clear.

Clearly the spools in the worn valve body are subject to much higher leakage when the fluid is hot than when it’s cold and more viscous.

Obviously I not saying that’s what’s happened in your case, I’m just making an observation. Might be worth checking the fluid for ‘glitter’ though .

Phil