Warning light: oil temp Gearbox

[discomarsh]

The transfer case oil temperature warning light came on whilst driving today, and after the car has cooled down, the light illuminates immediately upon start-up and remains on.

We checked three fuses (2 under steering wheel, related to gearbox and transfer case; and 1 under bonnet, related to gearbox) but all are OK.

We also checked the wires on top of the transfer case and these appear OK.

Car is 2003 D2a, TD5 auto. The last few days we've done 10 or so river crossings no higher than the bottom of the headlights. BUT, the warning light didn't illuminate until 2-days AFTER our last crossing.

When I touched the transfer case, it was bearly warm, so there's obviously not a temperature problem. Additionally, the car was serviced 2 weeks ago, so oil levels should be OK.

Any ideas??

[PhilipA]

Ah, now let me see!
Dead sender?
It's very common for the sender to leak in a little water and then short circuit. It happened to my RRC with my trans overtemp light where one of the senders is located behind the rad in the cooler line.
If yours is an auto it probably also has a sender in the cooler line as well as the one in the transfer case.
To check which one disconnect the wires of one then the other and see when the light goes out. I have never checked the wiring diagram but I am pretty sure they ground parallel not in series.
I bet on the one in the cooler line.
Regards Philip A

[discomarsh]

The transfer case oil temperature warning light ...

I mis-described the problem: it's not the transfer case light, but the gearbox oil temperature light.

[PhilipA]

Well ditto on my earlier post.
Regards philip A

[Urban Panzer]

Have to agree, dodgy sensor, VERY common problem.

[discomarsh]

Checked the ATF today, & it's full, as expected (recently serviced). So oil temp & level are not the reason for the warning light, I have to agree with my learned friends that the sensor is stuffed.

The sensor must be a bugger to replace, considering its location. Anyone know the costs?

[Urban Panzer]

The sensor is not expensive, about £20 UK, so $40 "ish" ?

Part Number UBI100030

I Replaced mine by removing the cooler assy completely, but I dont think you need to tbh, after doing another (gearbox cooler pipes) job I noticed you can most likely swap the sensor through the wheel arch liner access panel near the front anti roll bar.

If you have a nosy through this, you will see it in a few of the piccys.

www.discovery2.co.uk / Gearbox Oil Cooler Pipes (http://www.discovery2.co.uk/Oil_cooler_pipes.html)

[discomarsh]

Thanks for that link UP.

I wonder how one might prevent water ingress into the sensor in future.

[Urban Panzer]

The sensor is a sealed unit, i doubt water finished it off, I know of sensors that have failed on cars never even been in a puddle lol

[PhilipA]

Well mine died after 2 deep water crossings in Kakadu and Litchfield (600MM or so)
I cut it apart at home and there was evidence of water in it. Unfotunately "sealed for life" means just that. As soon as the seal fails the life is over.LOL
Regards Philip A

[Pedro_The_Swift]

can you seal the new one properly?