Help installing Trans temp gauge

[dvanbramer88]

I installed a Trans temp gauge in my 4l60E. Have the sender in the pressure port. The gauge's instructions stated to not use thread sealer because the sender needs to be grounded.

Anyway, I wired everything up per instructions. The illumination works. When i turn the key on, the gauge pegged at its lowest possible reading, well below 100. I thought ok, it's cold out this morning and it's just showing the real temp. After warming the truck up and driving to school, The sender remained pegged at "0" When i shut the truck off the needle creeps back toward 100. And when i turn the ignition on, it pegs back at 0. I tried switching around my wir on the back of the gauge thinking reversed polarity or something. With all the combinations, the gauge either doesn't work or pegs at 0.

When i get out of class, I'm going to check all my grounds and than use my multi meter to see of the case of the trans is grounded. That could be the problem.


I did test the gauge yesterday before installing it. I wired it up to a battery and grounded the sender to the battery and it worked fine. Put the sender in boiling water and it was dead on 212. So i know as of yesterday, the gauge worked perfectly.

Besides the trans case not being grounded, can anyone think of any more possible causes of failure to look into?

[The Roadie]

I think you're right about the ground, but the case should be grounded. I'm confused as well.

Why add a separate sensor? You didn't want to use Torque or a Scangauge to read the existing sensor's data?

[dvanbramer88]

I think you're right about the ground, but the case should be grounded. I'm confused as well.

Why add a separate sensor? You didn't want to use Torque or a Scangauge to read the existing sensor's data?

My scangauge software can't find anything resembling a trans temp sensor and the common belief on the GMT400 forums is that there is no temp sensor for the trans at all in the 1500's with the 4L60E. The HD's and trucks with the 4L80E have factory sensors you can tap in to.

Also, I don't have a smart phone.

Anyway. I went outside after class, yes I'm the dork that works on his truck in the school parking lot, I checked and double checked everything with my multimeter. The sender was grounded to the case, which has continuity with the frame and the engine and the exhaust and everything else. So i know we're good there. I changed my power source for shits and giggles and i checked the gauge's ground and everything else. Well after checking the wires with the continuity alarm, i found that the sender wire was on the (+) terminal and the power wire was on the (S) terminal. I switched them and now the gauge seems to be working fine as far as I can tell with a cold transmission sitting in park.

When i turn the truck off, the needle falls to 0. When i turn the truck on, the needle jumps up to a little below 100. Putting my hand on the pan, the transmission is still warm to touch from this morning.

Edit: I think all my problems arose from my power source to begin with. I was under the dash with the meter looking for a power source that was only on with the ignition. BUT i had the door open. So I might have grabbed power from something that is only hot with the door open AND the ignition on. So when I closed the door to drive, the gauge didn't have power, hence pegged at 0. But that's all a maybe. who knows