Transmission Oil Temperature...

[sam_d]

1997 Disco V8 Auto...

On my way up the coast yesterday I stopped by Stockton Beach for the briefest of visits before heading further up north to the Myall Lakes.

At some point during the trip between Stockton and Myall the Transmission Oil Temperature warning became illuminated.

Once I noticed I stopped and left the car to cool down but the light remained illuminated but took the drive easy. I had hoped that until leaving the car to cool overnight would sort out the problem but in the morning the light still didn't go away.

So, any ideas? Is it one of these things that'll clear with:

a) a quick disconnection of the battery negative lead or something simple like that;
b) 5 mins of a mechanic with a test book or;
c) a credit card hammering.

The car still drives well and sounds good. The Transmission oil levels look good and the oil looks nice and clean.

Thanks in advance

[TheEntertainer]

Could it be a faulty gauge?

[Bush65]

Have you checked the transmission oil level? Some warning lamps have dual functions.

[sam_d]

Have you checked the transmission oil level? Some warning lamps have dual functions.

Yup, that was the first thing I did. Plenty in there and all looking good.

[B92 8NW]

Since it's a D1 and has no powertrain ECU, no faults have been stored anywhere. It's likely the sensor has become faulty or there is a short in the circuit somewhere.

[sam_d]

Since it's a D1 and has no powertrain ECU, no faults have been stored anywhere. It's likely the sensor has become faulty or there is a short in the circuit somewhere.


Could it be a faulty gauge?

How does one go about checking the sensor / circuit? :confused:

[goldey]

I have had transmission temp light issues before. The first time the light went on I was on stockton beach. Pulled over and let the car cool down for good reason as the transmission pan was red hot :o:o.

Light wouldn't go away though, so next day I went searching and found that the wires to the transfer case sensor (which I still haven't been able to find :eek:) were shorting out on the transfer case, taped them up and the light went away.

Apparently D1's temp warning light on the dash is triggered by the inline temperature switch for the automatic (on the cooler lines, just behind the front chassis cross member under the radiator can't miss it) and a transfer case temperature switch (which as I said I still haven't found).

If the temperature sensor is working properly (the one for the auto), then it will read as an open circuit when it's in the cool range (below 130 deg C, I think :confused:). When it's in the hot range it will read as a short circuit and hence trigger the temp warning light on the dash. Easy enough to check whether it's the sensor or the wiring. Pull the wiring off the sensor and measure the resistance across the two connections on the sensor. If it reads close to zero and the car is cold then your sensor is rooted :(:(, time for a newy (about 75 bucks from memory). These sensors generally don't like being immersed in water or mud for too long, they tend to be a bit precious and failures are relatively common. If on the other hand the sensor measures like an open circuit (heaps of resistance) then it may be the wiring shorted somewhere. Measure the resistance between the two spade connectors that you just pulled off the auto sensor. If you get a short circuit (ie close to zero) then chances are you have a shorted out wire somewhere, time to start chasing the wiring out :mad:.

Of course, with mine now I have a different issue as I've just replaced the standard auto cooler with a big ass P38a Range Rover cooler (3 times the size) and elected to get rid of the standard temp sensor when renewing the cooler lines from the gearbox to the cooler. Now I'm using the P38a sensor on the side of the cooler, but it doesn't seem to be working.....hhmmmm:mad:.

Hope some of this is helpful.

Cheers

Goldey

[sam_d]

Hope some of this is helpful.


Thanks for that - I'll start hunting down wires and sensors tonight :)

[LOVEMYRANGIE]

Take the switch out and check it with a multi meter. These are just an on off switch. If it shows a switch closure at room temp, then its stuffed.
These are a relatively common failure that leads to all sorts of $$$ looking in the wrong areas.
Do this simple check first and take it from there.

If you dont know where t6he switch is, its the one on the trannie lines near the bottom of the radiator LHS.

[sam_d]

I located the temperature sensor last night and had a quick look. I think it must just have been a lose wire somewhere as the light went away after a quick play with the wires leading into the sensor.

At least I know what to do / look for if this happens again... :)

[JMAN]

Where is the transmission oil temp sensor located? If possible, could someone please post a photo of its location or describe for me what I should be looking at nd it what area?

I had the gearbox changed over in my 5 speed 1993 Disco and the light remained on from a cold start.

cheers,

John

[Scouse]

Looking at the picture in the parts listing, it's near the radiator.
Follow your gearbox cooler pipes towards the front of the car & you should see a sensor there.

[JMAN]

Thanks...will have a gander now.

[JMAN]

Cant find it...I see the pipes on the passenger side (2 of) but they dissapear under the radiator shroud... Dont really know what to look for.

[buzz66]

Not sure about the disco, but my 89 uses the coil type separate cooler mounted in front of the Air Conditioning condensor. The sensor is mounted on the left hand side of the cooler coil, access by removing front grill.

[JMAN]

I took it for a drive last night and funnily enough, the light went out by itself. Not sure what's going on. But it appears to be all correct now.
But I have a weird rattle coming from the rear passenger side that I cant put my finger on...very noticable at idle (not moving).

[Grimace]

But I have a weird rattle coming from the rear passenger side that I cant put my finger on...very noticable at idle (not moving).


Exhaust???

[nsgnomad]

Of course, with mine now I have a different issue as I've just replaced the standard auto cooler with a big ass P38a Range Rover cooler (3 times the size) and elected to get rid of the standard temp sensor when renewing the cooler lines from the gearbox to the cooler.

Goldey

Hi. at the moment I don't have an issue with transmission overheating in my 96 D1 v8 auto, but I do want to avoid it when towing my caravan.

When I looked underneath at the radiator etc, I found what I thought was an engine oil cooler (long cylinder with wire type cooling fins full width of radiator placed in front of A/C radiator) but no separate transmission oil cooler other than pipes leading to and from side of radiator. I considered using an aftermarket transmision oil cooler but the inlet and outlet were only 3/8" instead of the D1's 1/2" pipes. I have considered getting another engine oil cooler to use for the transmission but the P38a cooler sounds like a better idea. Would appreciate some more info on the fitting please (and maybe some pics).

Cheers,
Roger

[TheEntertainer]

Hi Mate,
If you get an EMS 2 from NATA (see my add up top) you can messure the exact temp and set high and low alarms on it!
Cheers
The Entertainer

[JMAN]

GRIMACE, yep it';s the exhaust making contact with the mud flap area. It appears the exhaust has shifted to the left (passenger side) and I cant seem to adjust it back without pushing it back the other way. Where the exhaust mounts from a welded hook to a rubber block behind the tow ball area, it's slipped towards the mud flap, causing metal on metal contact. I can push it away but it slides back again...

[slug_burner]

check engine mounts

[richard4u2]

I took it for a drive last night and funnily enough, the light went out by itself. Not sure what's going on. But it appears to be all correct now.
But I have a weird rattle coming from the rear passenger side that I cant put my finger on...very noticable at idle (not moving).
the light on mine comes on when ever it gets wet , when the auto gearbox gets hot when i am towing it dont come on so i just let it do its own thing :D

[paftd5]

interesting post, any chance on shedding some light on where to find the auto trans temp sensor, mine is showing 'red' on start up. thanks

[Pedro_The_Swift]

its shows on the RAVE cd to be screwed into the end of the cooler.

[blitz]

When I replaced my auto after stuffing it - totally my fault, somehow I have connected the sensors wrong because now when I put it into low ratio the gearbox temp light comes on??? :eek: :eek: :eek:

I havent had the low ratio light come on so I assume all ok??