Auto Transmission Cooler

[Ray!]

Since moving to East Gippsland, and with winter arriving, one thing I've noticed is that to travel much further before the auto transmission torque converter lockup operates of its own accord when going above 80kmh. I can of course lock it manually with the TC switch, but it's interesting exactly how long it does take to drive, before it does it on its own. I did notice this even in Melbourne a few times in winter, but it never took as long as it does down here. Obvioulsy I've never noticed this when driving in the High Country on trips, as we've rarely been able to drive at any great speed first thing in the morning.

I always thought that the auto transmission would have some sort of thermostat to allow the oil to heat up quickly to operation temperature, but clearly this isn't the case. The only other thing I can think of is that the oil cooler etc is quite efficient and that's why it takes so long to heat up the oil. Do others with an auto transmission, in colder climes, find this to be similar?

Cheers

Ray

[twisty]

yup, same. especially since I bypassed the stupid plastic radiator. I've read where, in Canada for example, bypassing the rad to aftermarket cooler prevented the TC lock engaging at all. They also mention different engagement times between summer and winter, regardless of cooling. I don't notice it that much because I don't think I care that much. My TC locks in every gear when above about 2200rpm (4.5l & Wholesale Extreme). Of course there is an optimum operating temp that would be about the same as the engine as they share the cooling system.

Ray, how much do you use the manual TC lock and under what conditions? Do you also drive through the brakes in 4low with TC locked? I'm debating if it's worth having a manual TC lock.

[Ray!]

Ray, how much do you use the manual TC lock and under what conditions? Do you also drive through the brakes in 4low with TC locked? I'm debating if it's worth having a manual TC lock.

I use the TC lock quite a bit. For rapid overtaking, I hold the foot switch down and then take it out of overdrive for very quick acceleration and passing. On hills, I use the TC lock to hold top gear, as the auto is prone to dropping down when it's not necessary. In other situatiions, I vary the use of the TC lock, in and out of overdrive, depending on the circumstances. I tend to use it as an extra gear when necessary.

Off-road, I never use the TC lock, as I've found it doesn't achieve anything. In first low it's locked anyway by the transmission.

It's well worth having, but you need to really work out when and where it's going to give you the best results. It took me quite some time to work this out, and at one point I was almost going to remove it, but thankfully I didn't. That's why I also think the simple manual setup is best, as it allows/forces you to think about what you're doing, a bit like having a manual transmission (which is how I use the auto anyway - a manual transmission without a clutch).

Cheers

Ray

[Gissmo]

Does the tc switch give you any better engine braking on hill descents? Just don't know weather to go that way or reduction gears I know there is a big price difference in the jobs.

[Ray!]

No, the TC doesn't improve or add to engine braking whasoever off-road. It's purely of value when on the road, especially hills or overtaking.

Cheers

Ray

[GPSTI]

Mine's the same - TC lockup much delayed in the cold weather.

I noticed the same on my VL when I had that (Nissan product too, of course) but don't remember it being an issue on the Jackaroo.

Not sure there's any mechanical problem induced in locking up the T/C with cold gearbox fluid. ATF is pretty thin chit even when cold.

There's plenty of debate about the location of transmission coolers, whether pre radiator or post radiator is best. In hot conditions, post is best, but in cold conditions the opposite is probably best.