Gearbox Overheat - False Light

SandMan

SandMan

Well-known member
Apr 25, 2004
118
0
60
United Arab Emirates
It's been months, but without any problems I remained quiet, offering only a tidbit here and there where I could help with my limited knowledge.

Now I have a constant gearbox overheat light on the dash. It is false, but how do I reset this annoying red gear light? New switch? Where is it? Computer reset?

My rig is a 1996 Disco 3.9 with no mods to the engine/electrical. It is a Gulf Spec with big radiator and no heater.

Thanks in advance!

SandMan
 
SandMan

SandMan

Well-known member
Apr 25, 2004
118
0
60
United Arab Emirates
Sharperover-Dude,

When I get up in the AM, it's about 15 C outside. I fire up the old gal and the light comes on. I'm no physics professor, but I don't think my gearbox is overheating at that moment.

Lately, the light goes off after driving awhile (overheat goes away when gearbox warms up) which is even less logical.

I just want to know where that switch is so I can remove it and take the switch down to the dealer for replacement. Trying to describe to Abdullah at the parts counter what switch I want is like trying to ask the 7-11 clerk in Little Rock for a nice bottle of Pino Nior.

Part in hand
Match part
Leave with new part

That's the system over here.

SandMan
 
S

ShaunP

Guest
It needs a new temp sender on the box, $20 AUD they often fail. Some cars have two, one on the Transfer box and one on the main box.
 
J

jec

Well-known member
Apr 28, 2004
48
0
Cloudcroft, NM
On 95 there were two switches. Transmission switch is in one of the hoses to the transmission cooler in the radiator. On 95 NAS version it is left side of engine compartment, directly below power steering reservoir. For transfer case, the manual says it's on the left side of the transfer case. Both work by grounding the circuit to turn the lamp on when they get hot. Try unplugging both to be sure it's not a ground in the wiring before investing in a new switch or switches. You should be able to test each switch for continuity with an ohmeter to see if one is bad. The transmission switch will have a copper crush washer which should be replaced if possible; at a minimum, don't lose it. Don't know about the transfer switch; never had to replace it.
John
 
L

LittleCountry

Guest
I think John is right-on. I was into my mechanic just yesterday regarding the same senario. Ensure both the transmission and transfer case levels and quality of the fluid is checked/inspected. Also make sure the connecters are cleaned and that everything looks good with the temperature harness itself. After the initial inspection, the problem with the trouble light intermittently eliminating, still persists... however the issue has been isolated.

Next steps: More time needed to access the warning sensors and harness, possibly replacing the sensor(s). -As long as I know that there isn't a physical problem with anything, I feel comfortable in pushing this issue to the back of the priority list...... The light really isn't that annoying to me anyway.

Total cost of the inspection $46 US (for a 1/2 hour on the rack) :(
 
SandMan

SandMan

Well-known member
Apr 25, 2004
118
0
60
United Arab Emirates
I love this forum.

You ask a question, get a few jabs, make a few comments, take a few more jabs, and then out of the blue someone answers the orignal question, like they really cared! 'sniff'

Excuse me...I'm a little teary eyed. Thanks to jec (John) and LittleCountry.

Turns out it was a bad trans switch which I located and tested with a meter. Saved the washer as described and reused. No more annoying light, and better yet, my overheat warning is functional again (just in time for summer).

Thanks again,

SandMan
 
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