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

Originally Posted by Tombie

Have you got barwork on the front of yours?

Yes, bull bar and two spotlights.

Disco1.jpg

Originally Posted by Barraman

Interesting!

The transmission temp in my 2015 D4 generally sits about 5oC less than the coolant temp - ie Coolant 100oC and transmission 95oC, when towing a 2.5t boat.

As I understand it the normal operating transmission oil temp is 95oC.

Yep, but once towing in the upper weight regions, it becomes a geometric heat generating progression. Plus I also have a high, very unslippery van and we all know about slipstream effects above 50mph/80 kmph.

When not towing mine sits at lower 90's for coolant.

Originally Posted by Barraman

Interesting!

The transmission temp in my 2015 D4 generally sits about 5oC less than the coolant temp - ie Coolant 100oC and transmission 95oC, when towing a 2.5t boat.

As I understand it the normal operating transmission oil temp is 95oC.

I think the 6 spd vs 8 spd makes a big difference in operating temps under load.

Based on the above and previous comments, and the fact the car behaved and the digital temp gauge did not move at all, id say thats all pretty normal then, 95 deg transmission oil temp, 104-106 coolant temp and 126 engine oil temp are std operating temps. Bullbar, bash plates underneath and lightbar in front

95degC won’t kill a transmission - but the normal convention is every 10 deg increase above 90 deg can halve the oil life and potentially transmission life.

So if doing extended running at 95-100 degC transmission temp just need to change the oil more frequently (say every 40K-60K instead of 80K).

Occasional use at these temps won’t be a problem.

Of course a transmission cooler can be cheaper than more frequent oil changes.

Originally Posted by DiscoDB

95degC won’t kill a transmission - but the normal convention is every 10 deg increase above 90 deg can halve the oil life and potentially transmission life.

So if doing extended running at 95-100 degC transmission temp just need to change the oil more frequently (say every 40K-60K instead of 80K).

Occasional use at these temps won’t be a problem.

Of course a transmission cooler can be cheaper than more frequent oil changes.

And the same can be said that both of those are cheaper than a transmission rebuild...

I’m in general agreement that the D4 cooling system is more than adequate even when towing.

Currently doing a spruce up of my D4 and the front end is off - the barwork being re-powder coated etc.
Whilst it’s apart I’ve decided to fit an Allisport intercooler, and because of the way it fits and the age of the vehicle now (10 years), have decided to bypass the in radiator cooler and fit an external unit.

I’ll be fitting it where the green section is on the image below:

Would love to know how the allisport intercooler goes. Have thought about one for my D3 for ages

Originally Posted by Tombie

I’m in general agreement that the D4 cooling system is more than adequate even when towing.

Currently doing a spruce up of my D4 and the front end is off - the barwork being re-powder coated etc.
Whilst it’s apart I’ve decided to fit an Allisport intercooler, and because of the way it fits and the age of the vehicle now (10 years), have decided to bypass the in radiator cooler and fit an external unit.

I’ll be fitting it where the green section is on the image below:

SO doing that you will virtually cover the complete air intake with new gear.The original intercooler was a lot smaller and sat down low, not restricting the Ac condenser or rad much at all.Although the 3L may be larger?And tranny cooler was part of the rad.

Hopefully the Ac condenser and rad can take the reduction in airflow.
Just saying,as we work with airflows across heat exchangers all day.
Something to be mindful of, which I am sure you are

On another note i wonder what temp the overheat light for the auto comes on?
I do know other brands come on at around 145 to 150 degrees.
If the auto is not locked up, it will also overheat a lot quicker than if it is locked up.