How to: Installing a Transmission Temperature Gauge

Parts needed and cost:
SunPro Water/Oil Temp Guage(Advance Auto) $16.96
3/8 Galvanized Tee $3.50+/-
3/8 Flare(male)/3/8 Pipe Thread(male) Connector $1.49 x2
3/8 Flare Nut $ .79 x2
Wire splice connector

Tools Needed:
Drill
Tubing Cutter
Tubing Flare Tool

In this pic I have fittings to connect to the rubber hose coming from secondary cooler. This location did not give very accurate reading so I moved location of sensor to before main radiator.

Remove center console compartment area by just it pulling up. Drill hole in upper compartment large enough to get sending unit threw. Run cable and wires threw hole and mount guage. On '98 XLT there is a wire harness connector behind console compartment. Locate red wire with black strip, this goes to dimmer switch. Use a wire splice connector and attach red wire from guage to the red w/black strip wire. Attach ground wire from guage to metal bracket that holds side of center console. Run cable from guage threw back of console and out by gas pedal.





Run cable up and over brake pedal and steering column. Locate where emergancy brake cable goes threw firewall. Remove rubber gromet from firewall and make a small cut, run sending unit and nut threw gromet.

Locate where cable went threw firewall under the hood. Look directly under brake master cylinder. Pull excess cable threw firewall (you may want help feeding cable from inside so as not to kink line).
Remove tranny lines from radiator, you need to remove both so you can pull upper line up enough to cut. You may want to use a small pan to catch tranny fluid that will leak from lower line. With tubing cutter cut upper line about 3in from lower bend. On lower part of line that was just cut cut again about 2in down.

On both ends of line install Flare Nut and use flare tool for 3/8 tubing and flare ends. Lowe's has flare tool for around $10.
Use pipe tape on all threads. Insert the 3/8 Flare(male)/3/8 Pipe Thread(male) Connector into tee. Insert 3/8 adapter that comes with guage for the sending unit. Install tee on lower line and then install upper part of line onto tee. Reattach tranny lines to radiator. Insert sending unit into tee (be carefull not to overtighten, adapter that comes with guage is very soft brass, I stripped it and had to but another guage just for the adapter). Use wire ties to secure cable from guage.


Go for a short drive to warm transmission and check level of tranny fluid.
Let me know if this is helpfull and if I need to change anything.

nice write up man ill be doing this after i get my tranny situation under control...

Maybe Im missing something, but you say to install flare fittings, but Im looking at barb fittings in your pics. Using these barb fitting, couldnt you install this temp gauge in line with the aux cooler. Mine are done with rubber hose so....

Where you have the sensor, is that in the line that goes back to trany or coming from trany?

http://www.explorerforum.com/forums/showthread.php?t=176798&highlight=transmission+temp+gauge

Ok, it can be done either way it looks like.

THANKS. I always appreciate a good photo illustrated how to thread !!

Gonna sticky this a bit to insure it gets adequate exposure for the work you put into it!

Nice write up! Why did you use a galvanized tee instead of a brass tee? All of the fittings going into it are brass.

Gatorblazer said:

Maybe Im missing something, but you say to install flare fittings, but Im looking at barb fittings in your pics. Using these barb fitting, couldnt you install this temp gauge in line with the aux cooler. Mine are done with rubber hose so....

Click to expand...

I explained in thread that I first installed it at the secondary cooler but could not get an accurate reading(temp. was too cold on the downside of both coolers to get reading on guage). I moved it upstream of the radiator and know I get the temp coming out of the tranny.

I had to use the galvonized tee in order to get clearence for the sending unit to allow better flow threw the tee. The 3/8 galvonized tee is bigger than the 3/8 brass tee.

ExploringNC said:

I had to use the galvonized tee in order to get clearence for the sending unit to allow better flow threw the tee. The 3/8 galvonized tee is bigger than the 3/8 brass tee.

Click to expand...

Yeah, the brass "probe manifold" T is an expensive part--about 25 bux, It has to have a real deep center neck for the probe.
Good idea!!!!

They make extension couplings which could be used, but they add to the cost, and bulk of the project.

Great write up.

Great write up! Love the pics!

Good write up. Mines going in once I finish the tranny leak. Would the pan have a more accurate reading then in the tranny line like your set up.

The pan would be more accurate but it requires more work to install the sensor.

ExploreingNC, Is the gauge you used mechanical or electric? Great deal for $16

I'm guessing it is mechanical- the cable that goes from the gauge looks pretty big. Mine is electric, didn't include a cable or wire, I had to run my own.

Transmission temp?

It looks like you have it figured out. What is the avreage temp the transmission should run at? I will be pulling a trailer with my 96 4 X 4,anyone know what is concidered a safe max temp would be?

thanks, Steve

wingnutt550 said:

It looks like you have it figured out. What is the avreage temp the transmission should run at? I will be pulling a trailer with my 96 4 X 4,anyone know what is concidered a safe max temp would be?

thanks, Steve

Click to expand...

Somewhere on this site they is a chart but I can't find it right now. I think normal temp. is 150-190.

many race trucks/cars or hotrods will run a before and aft trans temp sensor, so you can see the temp in the pan, then aft the coolers, to get an idea of how well its being cooled

Your 96+ trucks have a factory trans temp sensor in the pans, with the correct electric gage you can tap into the stock wire, no need to add a sensor to your pan.
I did it anyway LOL I use the port for my pan temp sensor as a drain plug also

Nice work!
$20 peace of mind = priceless!

well I purchased a B&M gauge kit, it came with sender, wire, T-adpter fitting and a plastic gauge mount the blended well on the steering collum. The instructions for mounting the sender has it going in the return line, the phone tech at B&M states that is the closest in accuracy to pan mounting. what I have found for temp is as follows; ambient air temp is 75 to 78deg and not pulling a trailer, after about 5 miles of warm up the temp comes up to about 125deg. and that is speeds around town less than 45mph. On the highway at 65 to 70 or a constant speed of 55 and above it drops to right at 100deg. My gauge readings are close to accual pan temp I checked the pan temp with a infered temp gun after pulling in to the garage and it shows about 135 deg. My question to the trany tech's out their is; I under stand that my coolers are working "testing the return fluid" but if my coolers, the factory one in the radiator and the aftermarket one I installed are reducing fluid temp to 125deg. What temp does the transmission heat the oil to and shouldn't that be a more accurate measure of oil wear tear. After all if the cooler scrubs 200deg off of the temp the oil still gets burnt. After all if you burned your french fries and cooled the oil your next batch of fries will still taste burnt. I am going to set up a sender on the transmission output line and will let you all know what readings i get. If anyone has already tried this please let me know what readings you have found.

thanks, steve