Thread: D2 auto transmission warning light on

Originally Posted by PhilipA

Transmax Z has a significantly higher temperature tolerance than + normal fluid and Castrol claims it runs up to 20C cooler than Dexron 3.

My trans light has never come on but then I don't tow over 1000Kg, but on the 15KM climb from Bellingen to Dorrigo with Exhaust at 600 and water at 100c there was no indication at all,even though I was in second most of the way so unlocked.

The stock cooler is very big. Is yours clean?
Regards PhilipA

Not sure. I have a stock cooler and Dexron oil was used and replaced every 40,000kms until 2013. Change of oil should probably make some difference.

I had this happen to me a while back after hitting a dip full of water hard. Don't ask!
Changed gear box fluid, cleaned every connecter & plug we could find, re connected & plugged everything & all good since.
Jonesfam

Originally Posted by candeniz

.....

I'd like to know what might be causing this issue. Is it the possibly degraded trans oil or the temp sensor at the oil cooler, or both? Having seen this happen twice over 18 months doesn't give me the confidence to tow anything heavy until I resolve this issue. I'd greatly appreciate your thoughts on this.

Cheers
C

Originally Posted by gavinwibrow

Apart from the obvious change the oil, maybe its time for an additional or larger replacement ATF cooler - worked for me (large addition in front of the coolant radiator).
.....

On the topic of the cooler.
I would suggest the simplest things first(and then test again).
Have you visually checked and confirmed that the radiators are not blocked in any way.
TD5 has a lot of radiators up front.
AC condenser. Do you have the AC on whilst this heating up is occurring?, if so have you tried/tested with AC off? Does it do the same thing?

if AC condenser partially blocked. Dirt, crusted up silt/mud, etc. it will affect the efficiency of the AC system(not so cold) and block air through to the trans cooler
Hard to see properly, but the cheapest(theoretically zero cost), and time consuming method would be to pull out radiator, give it a good flush through with garden hose whilst out, and do same for trans cooler.

Have you checked the level/colour of the trans fluid?

Temp sensor: my experience(in my tdi, but very similar temps sensor) mine came on, whilst very light duty driving(up hill). Slight panic(wasn't expecting it) checked trans level, but everything was hot, and fluid level is done when cold, idling in drive.
Drove gently home light on, off, on .. for a good while.
I have an IR temp gun, and trans sump was saying about 60-ish °C! Stopped panicking and thinking maybe an earth.
Next day from stone cold(trans fluid level good) ign on, trans temp light came on(stone cold) started up and it went out. It would come on randomly, maybe stay on, maybe off in a few secs. Ran like this until the new sensor arrived, and with new sensor fitted, all back to normal.

I'd reckon your sensor may be OK.

So check fluid level.
Radiators clean
Then assess the spending $s if everything else is normal.

I have had the trans oil temp light come on in the D2a,in low range, very soft sand, ambient temperatures around 40 degrees.

It also came on one time when we were stuck in soft sand, ambient temps very high.

Both times I did what the handbook said,all good.

Mine came on again today, after a water crossing. If it goes as per previous form, all will settle down in a few days.

I will do those checks, thanks. The last time the light came on, I believe it was certainly related to heavy towing. The first time was confusing as i wasn't towing anything, I was driving on a flat road and it was just before a whole day offroad trip in a national park. The light didn't come on again for the rest of the trip despite all the heavy work for the rest of the trip. The common thing between two instances was I had just downshifted and locked the trans in 3rd. maybe this was just a coincidence. a bit of mystery there...

Originally Posted by AK83

On the topic of the cooler.
I would suggest the simplest things first(and then test again).
Have you visually checked and confirmed that the radiators are not blocked in any way.
TD5 has a lot of radiators up front.
AC condenser. Do you have the AC on whilst this heating up is occurring?, if so have you tried/tested with AC off? Does it do the same thing?

if AC condenser partially blocked. Dirt, crusted up silt/mud, etc. it will affect the efficiency of the AC system(not so cold) and block air through to the trans cooler
Hard to see properly, but the cheapest(theoretically zero cost), and time consuming method would be to pull out radiator, give it a good flush through with garden hose whilst out, and do same for trans cooler.

Have you checked the level/colour of the trans fluid?

Temp sensor: my experience(in my tdi, but very similar temps sensor) mine came on, whilst very light duty driving(up hill). Slight panic(wasn't expecting it) checked trans level, but everything was hot, and fluid level is done when cold, idling in drive.
Drove gently home light on, off, on .. for a good while.
I have an IR temp gun, and trans sump was saying about 60-ish °C! Stopped panicking and thinking maybe an earth.
Next day from stone cold(trans fluid level good) ign on, trans temp light came on(stone cold) started up and it went out. It would come on randomly, maybe stay on, maybe off in a few secs. Ran like this until the new sensor arrived, and with new sensor fitted, all back to normal.

I'd reckon your sensor may be OK.

So check fluid level.
Radiators clean
Then assess the spending $s if everything else is normal.

Also a blocked trans filter will affect the temperature.