Thread: transmission temp light

It's probably a dodgy connection at the switch. It's located on one of the cooler lines in the engine bay & is susceptible to water ingress.

My light was coming on when I first got the car and on this occasion it was due to water getting under the rubber boot on the top of the sensor (as Scouse mentioned).
Later on though it was going off for real (135c) and subsequently a rebuild was required. This was after towing and sand driving.

Also be careful when revving while in neutral as apparently this has resulted in failure of many ZF22 gearboxes during emissions testing in Europe.
"Do not rev the engine in Park or Neutral: this will tear one of the forward clutch packs to pieces"

Are you referring to the 12v condenser fans rather than the mechanical viscous fan? you can ground the relay behind the glove box via a switch to force them on but in my experience it made little difference and if you do have a real overheating issue a cooler upgrade is the best approach and consider a switch to synthetic fluid at the same time.
Cheers
Mark

Hi discomark

I was referring to the viscous fan, it very rarely comes on, at least I've only heard a slight roar from it a couple of times. Had a bit of a look this afternoon and noticed that the thermo fans for the air con don't come on at all when the air is switched on. Still pumps out icy cold air, just not much when sitting in traffic. Doesn't seem right. Can't quite work out why the engine doesn't get hot but the gearbox does when offroad, low range and working hard

The viscous fan may not be fully engaging if its lost fluid. They have like a bi-metal coil that tightens as heat increases but if the fluid has gone they don't engage fully. I put a new one in last year as it was weeping fluid from the seal, they are only about $90.
I doubt that will help your transmission overheating issue though as even when they are working fully they don't seem to benefit the tranny cooler by much.
I also did not have any engine cooling issues when the gearbox was overheating.
In my experience the transmission does get hot when you are unable to achieve lockup, when lockup is achieved in lo or hi range I see a drop of 20-30c in temp at the gearbox cooler outlet where I have a sensor.
Many have fitted bigger coolers from a P38 etc to overcome this and thats what I ended up doing.
There is also a gearbox mod to get lockup to occur in 3rd but you would only do this if doing a rebuild due to the high cost.

The electric condensor fans should come on with the aircon so you may have stuffed fans or wiring issue. You should hear a click from the fan relay behind the glove box when turning aircon on so worth checking there first.

Check these older threads.
http://www.aulro.com/afvb/discovery-...gine-temp.html
http://www.aulro.com/afvb/discovery-...cooler-d1.html