Transmission Temp Gauge install w/pics

[Brian894X4]

This is what I finally did to install a transmission temp gauge. I know a lot of people have installed senders in the lines, and other various places, all of which are nice set ups, but I wanted something simple and easy. I wanted to install the sender in place of the drain plug.

The problem is the drain plug is M10x1.5. It’s a pretty small plug and after spending almost a week and countless hours searching the web and visiting a local instruments supply store, I came to the conclusion that there was only one temp sending unit on the entire planet that was that size. And there were no adapters in that size to mate to any other sender.

The sending unit is from VDO, part No. 323-091. And I had a hard time finding it. It’s not a common sender at all, but I finally tracked one down. The sending unit matches up with VDO transmission temp gauge part No. 310-107. The problem with this gauge is that it has a range of 150-400 degrees, whereas our transmissions generally run under 200 degrees. To make matters worse, the gauge face basically has 150-200 degree range as the first two hash marks and the 200-400 degree range make up the rest of the gauge range. (See pic in second post) So, most of the time, the needle is going to be setting near the low point.

On the other hand, if the needle is anywhere but the low point, there’s no mistaking that the tranny is headed for trouble. So, in a way it's a glorified idiot light. But at least I'll know the tranny is headed towards overheating before the light kicks on at 300+ degrees.

VDO makes two other temperature gauges. One with a range of 100-250, intended for water temp and one with a range of 120-300, intended for oil temp. Neither will work with this trans sending unit, even though VDO advertises all their sendings units as being 10-180Ohm range. I tried. They end up reading way to too low.

To install, I just removed the stock plug, and drained out almost exactly 5 quarts of tranny fluid (a lot more than the 2 quarts the manual says for some reason). I then installed sender. The head of the sender is smaller than the drain plug, so I couldn’t use the stock crush washer. I made a washer that fit, but I’ll be checking to make sure it doesn’t leak. The number of threads on the sender is the same as the stock drain plug. The sending unit itself protrudes another approximate inch into the pan.

By the way, does anyone know if the stock A/T oil temp idiot light is suppose to come on and then off with the ignition switch like most of the other lights? Because mine doesn’t come on at all. But I definitely have the stock sensor.

Pic 1: Draining the fluid. Strangely 5 quarts came out, even though the book says only 2 should have. But I see this is pretty common from other posts. I took the oppertunity to put back in 5 quarts of Mobil 1 ATF.

Pic 2: The new VDO sender in place. Fortunately, the sender is pretty well protected, so the chances of it getting damaged off road is not huge.

Pic 3: Shows the Land Cruiser A-pillar pod I ordered from "egauges.com". This is an Autometer part. Part no. ATM-15413. Fits the 2-1/16 size gauges. I painted it grey to sort of match the interior. It's shown here with a 100-250 VDO water temp gauge I was experimenting with.

[Brian894X4]

The VDO transmission temp gauge installed and running at operating temperature (just driving around town for about 15 minutes, at low speeds and with an ambient temp of about 45 degrees.)

Looks like here the oil in the pan is running at about 175 degrees. It's actually a little less as the angle of the gauge makes the needle look like it's reading just a touch higher than it is. Probably closer to 160. Now that I think about it, the range on this gauge is actually fairly useful. The only time it would be necessary to pay attention to the gauge is when it's reading between 200-300 degrees and there's a pretty wide range there. Beyond 300, the idiot should come on and damage is probably being done to at least the fluid.

[MadTripper]

Nice work.

[cc93cruiser]

Nice work indeed! Would you happen to know if the sender will work for the earlier 80 series tranny? Also, where did you order the parts?

[turbocruiser]

Very nice work! If I may make a suggestion, now is the time to get an Iron Pig Offroad (or similar) skid plate which will protect that wire from branches, mud, rocks or whatever. I'd tell the wifey something like, "The $xxx.xx I saved doing this will wash the $xxx.xx for the skidplate!"

[NLXTACY]

Awesome, another mod for under 100 bucks. Been ordered. By the way, I've seen some dual pods used. I think it was for an Acura that it was used. I will be mounting a coolant temp gauge as well.

[AppleTech]

I am still waiting for Scanguage to figure out the sending codes to use the stock sensor and pull the temps from OBDII. They say they are working on it...

[e9999]

nice!

can you tell if it would be just the wires or the whole sensor that would get ripped off if something were to snag the wires?

what kind of sensor is this (thermistor, RTD, TC)? It might be as easy as changing a resistor to change the scale if you really wanted to do, but then the face units would not match. Better to leave it as is. You're right. less than 175 may not matter. As discussed elsewhere, I only see 200 when I'm really working the beast. I was towing a 2500 lbs trailer a week ago and on the freeway it was still only about somewhere between 150-180 IIRC.

For those hesitant to muck with the plug, you can also glue or solder a flat sensor on the pan or on the plug. Or even use a wireless device as in bbq thermometer. Won't be as nice looking as this job though.



here is a chart showing the effect of temp on ATF life expectancy (found at random on web, so no idea if right, but seems consistent with what I've seen elsewhere):
Synthetic Oils Wholesale - Amsoil Dealer - Synthetic Oil, Lubricants Wholesale for Retailers, Commercial and Private Use This and other sources suggest that if you stay under 175 you're golden...

[calfj60]

Great write up and the install looks really clean...great work...

I will do a tranny temp and water temp when I get an 80...I am all about real gauges and not warning lights...

[Brian894X4]

Thanks much,

cc93cruiser:
I'm not sure if the 440/442 tranny has the same thread size on the tranny drain pan or not, but one way to find out is to see if the part number for the tranny drain plug is the same for a 1991/1993 as it is for a 1996. I use the year 1996, since some early 1995s have the old style tranny and just to be sure. Since my local dealer had the drain plug in stock, I'm guessing Toyota uses a standard thread size for most of its auto trannys. For this project I sourced the parts from egauges and several local parts stores.

But egauges.com should have everything for one stop order:

Truck, Van and SUV A-Pillar Mounting: Toyota Land Cruiser - egauges.com

VDO: Vision Black Series Gauges: Transmission Oil Temp. Gauges - Towing - eGauges.com

323-091: Temperature Senders: 400 Farenheit / 200 Celsius: 10-180 Ohms (VDO Range) - egauges.com

I had to paint the pillar to somewhat match my grey interior. I used the "light Acura grey" listed here:
Plastic Paint for Pods, panels, etc.: All Colors - egauges.com

turbocruiser:
Skid plate is definately on the mods list. Good suggestion

Appletech:
I have a feeling that Scangauge may never pull the tranny code, which is why I went this route. After reading some of the conversations people on here have had with them, it appears they need proprietary information that they are probably never going to get. I have the scangauge though and its awesome for the other readings.

e9999:
I have it set up so that if a branch or something catches the wire, it will just pull the wire off the sensor, no big deal. That's why the wire comes in from behind the sensor. I think the sensor is a thermister type. It has a probe and seems like a typical fluid/air thermister type sensor.

[reffug]

Originally Posted by turbocruiser

Very nice work! If I may make a suggestion, now is the time to get an Iron Pig Offroad (or similar) skid plate which will protect that wire from branches, mud, rocks or whatever. I'd tell the wifey something like, "The $xxx.xx I saved doing this will wash the $xxx.xx for the skidplate!"

your intricate use of logic always makes me chuckle....................

[mot]

COOL!!

[calfj60]

Thanks for the link to egauges....Ordered my Autometer stuff from them last night...now just need to finish the truck hunt...got a couple in mind...

[jditom]

Nice job Oregon dude

[Cruiser Jimmy]

Originally Posted by Brian894X4

I know a lot of people have installed senders in the lines, and other various places, all of which are nice set ups, but I wanted something simple and easy. I wanted to install the sender in place of the drain plug.

Looks nice.
Just remember it's not the true temp. A temp from the circulated fuild will give you a more accurate reading of the heat being generated. The pan is going to cool some of the sump fuild at the current configuration as well.

Any data yet?

[Brian894X4]

So far, I've only made short trips in fairly cool weather, but the highest I've seen is what's in the picture at about 165-175, which was about 15-20 minutes of low speed city driving and a few miles on some back country roads.

The only other time is my 4 mile commute to work which takes about 10 minutes. The needle is barely on or above the 150 line by the time I get to work.

If operating temp is 120-180 degrees or so, then it would be interesting to see how much higher in temp the fluid is in other parts of the tranny.

[e9999]

the numbers I mentioned are at the beginning of the line to the rad, right after the ATF leaves the trans

[TrickyT]

Originally Posted by Brian894X4

...By the way, does anyone know if the stock A/T oil temp idiot light is suppose to come on and then off with the ignition switch like most of the other lights? Because mine doesn’t come on at all...

The A/T temperature light, together with the low oil level and brake fluid level/parking brake lights, should come on for a few seconds each time you turn the ignition switch to the "start" position.

[overhanger]

Originally Posted by Brian894X4

So far, I've only made short trips in fairly cool weather, but the highest I've seen is what's in the picture at about 165-175, which was about 15-20 minutes of low speed city driving and a few miles on some back country roads.

The only other time is my 4 mile commute to work which takes about 10 minutes. The needle is barely on or above the 150 line by the time I get to work.

If operating temp is 120-180 degrees or so, then it would be interesting to see how much higher in temp the fluid is in other parts of the tranny.

Let us know what the temps are after ten miles or more at speeds above 60 mph. I'm guessing they will settle in closer to 180+ at prolonged hiway speeds especially if there are elevation changes.

[Cruiser Jimmy]

One more thing I learned from the University of Hardknox. If at some point you start to see the temp go up while you're on the highway for an extended period of time, the torque converter's lockup is starting to fail.

Overhanger, so what have the temps been with the Oz VB?

[619TOY]

Nice! I like it. Maybe I will finally get that gauge done afterall. I change my ATF on the 80 every oil change and it's always nice and fresh smelling and pink so maybe my driving like a little old lady really isn't stressing anything out

Maybe once I finally get that S/C mounted in the 'Runner. Too many projects, too little time

[e9999]

Originally Posted by 619TOY

Nice! I like it. Maybe I will finally get that gauge done afterall. I change my ATF on the 80 every oil change and it's always nice and fresh smelling and pink so maybe my driving like a little old lady really isn't stressing anything out

snip

wow, even I, admittedly superanal about such things, am not changing my ATF at every oil change...

unless you are going synthetic oil and changing it every 15K, then maybe then...

[Brian894X4]

Originally Posted by overhanger

Let us know what the temps are after ten miles or more at speeds above 60 mph. I'm guessing they will settle in closer to 180+ at prolonged hiway speeds especially if there are elevation changes.

I spent a few good hours today in combined highway driving and very bad rush hour traffic with about 75 degree ambient temps. The trans temp never went above the 175 degree line and mostly hovered a tad below it, probably averaging around 160. I imagine the trans wasn't exactly working hard today, though. No major hill climbs or anything like that.