Transmission Temp Sensor

Lin · August 13, 2010, 02:26:51 PM

Inspired by another thread, I was wondering what options there were for adding a transmission temperature gage to an Allison. The preference would be to locate the sensor in a way that did not require draining the oil.

luvrbus · August 13, 2010, 02:49:12 PM

Lin, there is a spot on top of the torque converter housing where the sensor installs no need to drain any fluids

good luck

thomasinnv · August 13, 2010, 03:20:18 PM

i have an Alison 740. can you shed some light on exactly where the port is to install the sensor?

JackConrad · August 13, 2010, 04:21:39 PM

Near the top of the transmission on the driver's side, close to where it bolts to the engine. Next to the hose fitting for the transmission cooler hose outlet to the cooler. Jack

Lin · April 26, 2011, 03:13:09 PM

I'm finally getting around to getting a temp gauge for my Allison 647. Just to make sure I have it right, is it the 3/8" plugged hole that is just below the transmission cooler hose? Someone also said that I could use the pressure test port that is near the shift lever, but I don't think that is really in the oil flow.

opus · April 26, 2011, 03:22:43 PM

My 643 is in the pan. I believe the 647 has it in the pan as well.

luvrbus · April 26, 2011, 04:00:21 PM

Lin, you want the temp gauge on the converter oil out side if you don't have the plug on top some did some didn't you can install it on the line or the in on the filter I would not install it in the pan the converter temp is what you need to monitor

good luck

Lin · April 26, 2011, 05:27:58 PM

I'm not going to do the oil pan since I do not want to drain the system. I will try to check for a port in the torque converter tomorrow. In any case, I am trying to determine the port size so I can get the right sensor. Clifford, I had thought that the cooling line out would be as hot as it gets, and therefore thought that the small port below it would be decent. Would there be much difference between that and the torque converter temp?

opus · April 26, 2011, 05:40:43 PM

The sensor has to correspond with your particular gauge as well.

Lin · April 26, 2011, 05:49:18 PM

Thanks, the gauge I was looking at can come with a 1/8, 3/8, or 1/2 inch sensor, so that is not a problem. I just have to verify the port size before I buy it.