Thread: D3 loss of drive on long climb

Peterall,

If you do a search of the forum there are some similar threads and posts about this.

I had a transmission warning flash a couple of times climbing a very long steep climb in the Vic High Country. No loss of power or drive but just a transmission failure warning, noting limited gears available.

I put it down to the transmission overheating due to the length of the climb in low range. As I was close to the top of the climb, I stopped for 45 mins once at the top to let everything cool down and never had the problem since.

My theory, based purely on speculation is that the prolonged uphill travel, usually under strain means fluid transfer is somehow reduced and with the limited amount of transmission fluid moving through the box the transmission overheats.

As the ECU is smart enough to shut you down before you stuff anything, letting it cool and restarting fixes the problem.

Again, no technical or mechanical intelligence goes into the above summation, just some bush logic.

I assume others with a better understanding will come along soon and provide feedback.

Regards,

George

The only time that an auto transmission generates heat is when the torque converter is not locked up, i.e. when the torque converter is working.

When the TQ is working, there's a certain amount of slip and this creates the heat. So it sounds like the transmission may not have been locked up when it was climbing up that long hill.

Perhaps it may be better to manually downshift the auto to 4th or 5th gear and let the TQ lock up. Whilst the revs may be higher in a lower gear, there are two benefits - the engine will be revving in the max torque band and the gearbox is not generating heat coz the TQ is not "working".

How can you tell if the TQ is locked up or not? If you gently vary the throttle pressure (by curling up your toes) and observe the tacho, the revs should not flare up and down. When the TQ is locked, the rev dial will have a linear relationship with the speedo dial, as there is no slip that would vary that relationship.

It's my humble opinion that sometimes the auto may need a bit of "driver intervention" to get the best possible outcome when towing something heavy up a long long hill.

I have an 06 TDV6 coiler and tow a 1500 kg caravan. I have also experienced similar symptons on long steepish climbs.

The first time it happened was only a month after I'd bought the car, it had recently been fully serviced (80,00km) and had the fuel pump recall completed. Hauling out of Lithgow towards Bathurst and I felt a shuddering in the drivetrain.
Had the car checked by the Ford (ex L/R) dealer in Dubbo. They were very helpful and passed it as okay. No further occurrences that trip but it was mostly flat driving.

Next time I was pulling up Mount Ousley, same symptoms. Car was due for a service so I spoke with Ayers about it. They did the double flush and replaced the trans fluid @ 93,000 km.

I have just completed a 3,000km caravan trip to Broken Hill and the car towed brilliantly (except for the saggy rear scraping on the dirt crown - need to look at some springs I think-but that's another story). The only hiccup was on the way back on a long climb into Lithgow I felt the loss of power again, at the time the trans had changed down to third and engine was doing nearly 3000 rpm. Flicked the lever across and manually changed to 4th, revs dropped and car pulled up the hill no probs. On approaching Mount Vic I changed down manually and held the motor in the torque band and she pulled up no probs again doing the posted 60 k limit.

It has me stumped and I'm fairly mechanically minded. It seems the car likes a bit of human input every now and then. They're a quirky beast but you gotta love em.

I have experienced the transmission going into fail mode with limited gears available offroad a couple of times. Usual circumstance are cresting a steep hill and I notice the transmission going into fail mode. Have spoken to the dealer about it and had the codes analysed and while not conclusive their theory is that as the transmission monitors input and output speeds, if it calculates a difference perhaps caused by a little clutch slippage it will go into limp mode. Turning off and on fixes the problem. Clutch slippage perhaps caused by cavitation or momentary oil starvation??
This has only happened maybe four times in 120000Km so I'm not concerned.

Regards,
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