Thread: Extra gearbox oil cooler for towing Y or N ?

Originally Posted by gavinwibrow

Aux Transmission Oil Cooler | MODIFICATION | Davis Performance

I didn’t know that. Thanks.

Would anyone know how hard an extra cooler would be to install on an 8 speed? I haven’t done much mechanical on the D4 but I did everything mechanical on the D2

Two options,, in the grill or underneath..
fitting should be well within your grasp..

Another option could be a dash mounted gearbox temp gauge. The mechanic who serviced our D4 recently mentioned a kit for the D4 with IIRC several critical temp readouts permanently visible.

I guess the negative of that idea is it's no help if it's stinking hot and you have to get to a destination.

I will be fitting one of the overheat alarms to mine. These double up as a temp guage and will save your engine and gearbox if losing fluid and overheating etc.

After years of towing with an auto i always use the gear stick when in hills and working hard. A lower gear and a few revs will reduce the overheating of transmissions. In the old days it was recomended not to use overdrive when towing.

If it is really hot weather reduce your speed and save your vehicle and fuel bill.

Have you had your gearbox serviced and the oil flushed and changed ? I will get this done to mine before heading out with the caravan next

Ian
Bittern

The D4 already has an overheat alert.

Hot weather and speed don’t correlate directly.
Hot weather and LOAD do.

I see many a Shed Dragger over here in 43°+ towing and wonder why. Just set up somewhere, crack a can and relax.

I'll be honest that I haven't read this thread in it's entirety. But thought I'd share a few thoughts:

The GAP Diagnostics IID Tool is capable of displaying the automatic transmission temperatures (this is used when replacing the fluid as it's meant to be at a certain operating temperature for the final refill - 50*C or so if I recall correctly). Drive around and monitor it to see what temperatures your seeing - this should be your guide as to if you need additional cooling or not.

Then have a read of Automatic Transmissions at < Transmission Oil > - this website is recommended by Ashcroft Transmissions (they recommended it on their website at Ashcroft Transmissions ), a mob in the UK that seem to know a bit about the ZF gearboxes. The key points of this are:

There is a minimum operating temperature (65.5*C) and it is possible to overcool - i.e. cooler is not always better. Running for extended periods below this will also cause additional wear and tear.
Ideal operating range is 79.5 - 93.3*C
There is a maximum operating temperature for short bursts (135*C)
And a maximum (149.9*C), after which internal damage begins to occur.

So using this data above and your IID Tool to see your current temperatures you should be able to determine if additional cooling is needed and/or beneficial - thus answering your own question.

Also I suggest noting the guidance of the table that provides a correlation between the operating temperature and length of time and service live of the ATF. Perhaps if your in the upper end of the safe range then the solution is rather to just replace your ATF more regularly rather than fitting a second cooler.

Originally Posted by Mike.C

Another option could be a dash mounted gearbox temp gauge. The mechanic who serviced our D4 recently mentioned a kit for the D4 with IIRC several critical temp readouts permanently visible.

I guess the negative of that idea is it's no help if it's stinking hot and you have to get to a destination.

A Scanguage 11 will give you auto oil temp as well as others. (engine coolant, voltage, fuel consumption, inlet air temp, etc)
At around $250 it may be your cheapest option.

Originally Posted by John_D4

I didn’t know that. Thanks.

Would anyone know how hard an extra cooler would be to install on an 8 speed? I haven’t done much mechanical on the D4 but I did everything mechanical on the D2

John, when you get it all sussed (including for a 2.7L 6 speed option) I'm sure you will post here

On this trip, I plan to again post readings of coolant, engine oil and ATF temps pulling the brick. I'm very much inclined towards an AFT cooler as stage 1.
Cheers Gavin