Thread: Adding temperature sensor to 300tdi automatic

Does anyone know if this is true and if so what sensor

Hi Grizzy,

The temp sensor that you are inquiring about is on the transmission cooler this located at the front bottom of the radiator. it is a open/close type sensor as it only turns the light on and off once passing the set temp.

there should be a empty spot in the dash to stick in the light

A mate of mine, into hyper performance and turbo toys, uses a standard Dick Smith or similar thermocouple, hooked up to a digital readout. The 3 figure LCD\LED unit is powered from the car system and the thermocouple device is powered from that when plugged in. He just uses a stainless clamp to hold things in place on turbo piping etc. For a gearbox? Why not try a plain old water temp guage. If there is provision on the gearbox for an internal sensor, maybe something as simple as a mechanical temperature guage can be fitted into the side or top or where ever the sensor is located. Just a couple of suggestions.
I am pretty well known for my distrust of the new fangled electrickery stuff.

On the lighter side, cut a hole in the floor and have a feel of the side of the gear box. If you can hold your hand lightly on the hot surface, it is not actually hot, only about 140 degrees F. The human hand can tolerate this, but not much more. This is old fashioned steam engineers knowledge. 140 F is not hot for oils. Most engine oils only start to truly perform from about 170 F up to about 220 F, gear oils not that much different.

Hope some of this helps.

Shorty.

Originally Posted by Grizzly_Adams

G'day all,

I converted my '94 300tdi Defender to an automatic last year and one of the things on my list is to add a temperature sensor or alarm thingy to the automatic.

As the automatic is from a 300tdi Discovery (zf HP22) I have been told that some of them (all of them?) had a spot for a sensor on them as there was a light on the Discovery dash?

Does anyone know if this is true and if so what sensor(s) have people fitted apart from the standard? I know on my dash there is no spot for an automatic warning light like some people have told me before...

If you look at the warning lights on your instument panel on left of the tacho are 2 lights on far left and 3 closer to tacho......the top one of those 3 is the blank red lens and has a symbol of a gear wheel with a thermometer inside it........

........the thermo switch fits in the cooler line from the auto trans. to heat exchanger inside the LHS tank of the radiator [assuming you've swapped in an auto trans. radiator] OR fit a really BIG oil-to-air auto trans cooler - these ZF's generate a lot of heat!......and you don't want to run hot all the time, it shortens the life of the fluid.....which shortens the life of the transmission BIG TIME!......

BTW - using fully synthetic auto trans fluid is avery good idea!

PS - It also is/should be connected to a similar sensor/thermo switch in the Transfer Case!!!

Mine has a temp sensor in the bottom of the box. Temp is the biggest killer of the ZF boxes.

ZF = Lamborgini. Made in the Italian Alps? Where it snows, and it's cold?
No wonder the ZF box is frail in the heat.

Shorty.

Originally Posted by byron

If you look at the warning lights on your instument panel on left of the tacho are 2 lights on far left and 3 closer to tacho......the top one of those 3 is the blank red lens and has a symbol of a gear wheel with a thermometer inside it........

Don't think my model came with that particular lamp - have a look at my dash - btw. the tacho was one I added myself recently, 300tdi Defenders (at least, as far as I know) didn't have tacho's at all.

You can't really see it in the photo, but the 2 red lamps that look like they've got nothing on them have A) a fuel bowser (I guess it's a low-fuel arning, however it has never done anything) and a 24volt battery symbol

Originally Posted by shorty943

ZF = Lamborgini. Made in the Italian Alps? Where it snows, and it's cold?
No wonder the ZF box is frail in the heat.

Shorty.

Ummm, hate to spoil a good story with a few facts, but ZF is German........and its hardly a "fragile" transmission......one of the most reliable in the world, of all time.......ONE of I said, before people start firing!