Trans temp sensor

Now that I have installed my trans cooler, I think I'll go ahead and install the trans temp sensor for the gauge that I have mounted in my pillar pod.
Has anyone here added a temp sensor bung to the trans pan? Where would be the best spot on the pan to put the sensor? Side, front, back?
I'm not going to get a SG since I have a gauge mounted in the pillar pod already.

 

I'll be doing this on my next oil change. Still trying to figure out the best spot to put the sensor.

 

Weld in (shouldered) bung arrived today, threads are 1/8-27 NPT. Picked up a new pan gasket on Thursday. The level of idiocy was amazing at the dealer. Told the guy at the parts counter I needed a transmission pan gasket for a 2007 Tacoma Prerunner 4.0L with automatic. He proceeded to name off the engine sizes available, I repeated 4.0L 1gr-fe V6. To which he replied "that's not an option for a '96.
Anyways, got the correct one at the end of all the BS. So, probably going to do it next month when I do the oil change and tire rotation.

 

If there isn't an option to splice in a sensor into a flexible cooling line, there should be .

 

Putting it inline can be done. Cut the hard line, install a compression T fitting.
Installing in a rubber hose would require a T fitting with a ground strap/wire.
I was hoping there would have been a test port that I'd be able to use. But, by putting it in the pan, I can monitor temp of fluid in what I think is a reliable manner without having to use an OBD device.

 

Sunday, I will be pulling my pan and drilling it for a weld in bung. Already talked with the guy who does welding for me and he said Monday won't be a problem to stop by and get it tig welded. I'll take pictures while doing the install.
Stopped by the dealer today and got 6qts of WS ($9.95/qt).

 

If you swap something into your truck and ask for a part most Toyota Parts people are clueless .

There whole System is set up via the VIN telling them just what is in your truck.

Then as the older parts people retire it just gets worse.

Since some transmission pans are quite shallow make sure you have enough room for the sensor to have enough clearance .

Yours might be just fine

I ran into that years ago doing the welding of the bung

 

A little pic heavy. Got the pan off, cleaned up and hole drilled for the weld in bung. Placement of the sensor is on the driver side almost even with the filter pick up tube.
These pictures show what you will find when you take the pan off. Nothing unusual. Red fluid dripping from everything.

This picture shows what was cleaned off of the 4 pan magnets.

Color of the fluid after draining.

Paper towels used to clean the bottom of the pan. Brown oil on the first towel is from cleaning the spout of the drain pan not trans oil.

Pan all cleaned up.

To check clearance, I stacked the 4 magnets where I wanted to put the hole. They are about the same height as the sensor would end up being. Taped down to keep RTV off of them. RTV is used to verify that nothing would touch. I measured the location of the pickup and drew it onto the pan with soapstone so I could better estimate where to put the sensor.

Don't mind the circle scratches. Had to adjust for the slight curve of the pan.

 

Sensor bung. My drill bits were either too small or a little too bit. I drilled it out too big, which will give me a nice shoulder to weld. Ill post the pictures of that tomorrow after it gets welded up.

Pilot hole definitely helps prevent walking of the larger drill bit.

Drilled out.

Debating on if I will weld the bung to the outside or inside, I'll have to see if the electrode can reach all the way around if welded to the inside.

De-burred, sanded clean. Used a small 150 grit flap disk. Washed the pan with hot soapy water. After it gets welded, it will be washed again and then painted.

 

Project complete. Decided to use silver solder instead of tig welding. Got everything put back together and wired. 5.5qt of new tranny fluid to get it full (put 6qt in, let it warm up, then removed the check bolt and about .5qt came out). On to the pictures.
Outside of the bung. Soldered in. Silver solder flowed really well to seal it up.

Inside soldered.

How the sensor will sit.

Sensor sits below the level of the check tube.

Nothing fancy. Cleaned it up with a wire wheel, taped off the area, then prime & paint.

New pan gasket. Remember to put the magnets back in place.

Pan installed and sensor wired. Don't remember if I mentioned it, I found that one of the bolts had recently been removed. Threads were nice and shiny, had a nice circle of clean black paint. It would appear that while my truck was in the body shop, they needed a bolt for another vehicle and decided to take it off my tranny pan. I will have to go get a new one, until then, I used a phillips head bolt. Used a paint pen to mark the tightening sequence. It is a modified T4R sequence (T4R has 19 bolts instead of 20, so I changed 18 to 19 and 19 to 20 then made the extra #17). Wrote the D&F mileage on the bottom.

Temp sensor is working. This was right after I finished. I'll see where it runs when I drive through the mountains on Wednesday.

Welp, that's all folks.

 

CLEAN writeup! Nice work! What temps are you seeing in normal stop and go traffic?

 

I haven't really been in stop and go traffic since I installed it. Driving 100+ miles of relatively flat with a few good hills, it got to 125 and pretty much stayed there. Driving up past Crater Lake with hills and windy roads, it got up to just under 150.

 

Closest to stop and go traffic I got into was on Wednesday. Sat for a while waiting for a front end loader to clear a rock slide enough to open one lane for traffic. I let it idle in drive for 15 minutes. It got up to and maintained just under 165.

Zero leaks, only issue is that the bulbs for the two gauges are different colors. Air pressure is more orange while trans temp is white. Going to have to fix that. Eventually.....

 

That seems reasonable enough. Warm enough for the conditions, but not hot enough to degrade the life of the trans fluid.

 

I don't have towing planned yet, but when I do, I'll post temps. Hoping to go get a travel trailer in the next month or two, so I'll be getting temps with 3200lbs in tow.

 

Update to this. Spent 3 hours working my way through the LA area, pan temp got up to ~165*.

 

Nice write up OP
Crazy Toyota doesn't have a threaded, dry port somewhere on the xmsn...in any case, your wet install will be most accurate.
Temps are good. Thanks for posting!!

 

Subbed

 

@windsor, So I am just curious as to why you did not want to simply use the 2 trans oil temp sensors already in the truck with an OBDII sensor?

Does you 07 not have them? You dislike the OBDII?

 

The 07 does have OBDII capability. I used my SnapOn Ethos* to watch temps when I moved from AZ to OR. But, I wanted to use a gauge in the pillar pod.