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Do you have a trans temp gauge?

  • Yes

    Votes: 5 23.8%
  • No

    Votes: 16 76.2%
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What's the thoughts on a trans temp gauge, yea or nay, why or why not.
Hi Gary, If you have a higher stall torque convertor (2200 rpm and above) or do any towing with your wagon its a good idea..if your trans fluid temp is getting above 250 degree's its time to pull over or add a bigger cooler. :) I have one in my camaro because its got a 5500 rpm convertor



 

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If you are pulling steep grades and towing heavy loads, then I could see the need for that.

Or drag racing with specific high dollar trans stuff.
 

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I run a temp gauge with a 200-4R in my '68 Camaro with a 2200 stall torque convertor. The reason heat is the main killer of automatic transmissions with lock up tq convertors. The number one failure of automatic transmissions is overheating. Nothing like peace of mind. A temp gauge is the only way of knowing if the heat exchanger/cooling system is adequate during driving conditions.
 

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Install the sender in the pan (where it should be). Mine threads into the drain plug.
 

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Not all aftermarket drain plugs are created equal.

Most of them are a brass fitting and jam nut with a gasket. You just drill a hole in the pan and screw it together. There is a 1/8" pipe plug for the actual drain plug.

The thing about this type is that
1. They leak.
2. The 1/8" pipe plug is too small to drill for a temp sender.

A better way to go would be something like this.

Weld a pipe fitting or coupler in the pan that's the same pipe size as the temp sender. Then you could use the sender as a drain plug.

Or you could weld that fitting into the pan and just use it as a temp sender, and do a separate drain plug with a welded fitting. I like to use a plain threaded plug with a nylon washer like the one on a factory engine oil pan.

But usually when you drain the pan, you're going to drop it and clean or replace the filter, and you'll have to disconnect the sender wire anyway. So having a double duty sender/drain makes a bit of sense.

I've also put the sender in the case next to the dipstick/filler tube on a race car where there's good access. That's OK but I'm not sure I'd do that on a street driven car. But I'm sure you could make it work.
 

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Actually, having the sensor in the pan is not ideal. Some transmission models have poor circulation in the pan so the worst place for the sensor is at the drain plug because that's usually the lowest spot and the fluid does not get as warm as the rest of the capacity does. If your transmission has a flat pan, then it's not as bad because the circulation is much better.

My pickup truck has a weird shaped pan (4R100) with several valleys formed in the pan itself. I had my sensor in the pan and it barely registered 140 degrees. Which I knew was wrong because it was 115 ambient temps, I was in stop and go traffic and my scan tool was telling me the temps were actually about 170 degrees! (my scan tool plugs into my OBDII port and processes the signal from the factory sensor). I then climbed under the truck and used my IR gun to check the pan temps. Depending on where I took the reading on the pan itself the temps could vary by as much at 25 degrees.

I then relocated the sensor to the factory test port and checked everything again. Now the gauge is much more accurate and responds faster which is important because I tow a heavy load up some pretty steep grades and I need to know if my trans is getting hot. With the sensor in the pan it took too long for temp changes to register and by that time it could be too late. Now keep in mind that I am talking about a fairly heavy duty trans with 20 quarts of fluid and a pan designed for a 4x4 (with the weird shaped bottom). I know many of you are running TH350 or TH400 automatics with basically flat pans and lower capacities, so the fluid temps may equalize pretty well. I am just pointing out that the pan is the last to know as far as real fluid temps are concerned so putting the sensor there isn't really telling the actual story.

So, if you tow or run a high stall converter then you may wish to get a temp gauge and then find a good place for the sensor. Some older automatic trans may not have a test port so the pan may be your best (only) choice. You could also install a T-Block in the cooler line as it exits the case and put the sensor there. This will give you a pretty accurate reading. However, be careful that your sensor does not restrict fluid flow or you'll be doing more harm than good. There are products on the market just for this purpose so you may want to research them and find one that works for your equipment.

If you are running a computer controlled trans with a lock up converter, then you may be able to tap into the factory sensor that is inside the trans with some sort of scan gauge. DashDaq makes a nice unit that plugs into the ODBII port so this may be a cool option for those LS guys out there that may be using the factory PCM. If you have a test port, then you can put your sensor there. Again, just make sure that your sensor tip does not block the fluid flow. Some brands are different than others so make sure you check with them and make sure they took this into consideration when they made the sensor. I think ISSPRO makes sensors that are specific to the transmission model so they may be a good choice to check.

Either way, I am a believer in supplemental trans fluid coolers. I prefer the TrueCool Max but there are many good ones on the market so you can shop around and see what fits your budget. Most of the new heavy duty diesel pickups have separate trans fluid coolers so you can scour your local wrecking yards and see if you can find one that fits. The trans cooler from a Ford 6.0 diesel seems to be very popular and they fit in the Tri-Fives quite well.

For my 55, I do not plan on installing a trans temp gauge because I'll just be running the stock 265 with the Powerglide and the stock converter. When I finally get it running, I'll probably take a few readings of the case and pan with an IR gun and see what I get but that's about it.

Hope this helps. :)
 

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Chevy Chase: I have a 200-4r behind a stock 350 in my 57 wagon, and it runs hot. I don't yet have a guage on it, but that's "in route" as I type this and will soon be installed.

I'm curious to know what the temp range is that your trans runs at, and what you consider to be "hot enought to warrant attention'.

Thanks,
Paul
 

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Wagon Crazy, My 350 V8 engine runs around 170 degrees on the freeway at 75 mph. It has an aluminum radiator and new Classic Auto Air, 3.70 posi, 200-4R. The transmission temp gauge reads 148-155 degrees after engine is up to max temp. It has been unseasonably cool in the SF Bay area. Temperatures have been in the low 80's with about 30% humidity, the last few weeks! WOW!
If the transmission temp rises above 175 degrees you should find out why and remedy the situation. Dextron III says the ideal transmission fluid temperature is 160 degrees.
 

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If I was to add one,,or two. it would be to the exit line going to the cooler,,then maybe another one after the cooler at the trans infeed port,,to see how efficent the whole cooling system is (you know how hot it is going out, is it any cooler going back in?? how much??)

Since I run two coolers, I am not going to worry about it.
 

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I used one of the VA vent housings to mount a trans temp gage here.


It's kind of hard to read there though.
I also used the drain plug trick with good success.
I had to retap the hole for the sender (or did I? Can't remember now:rolleyes:)
It works fine.

As you can see, the pan I have has a drain plug.
It leaks a little, but the sender doesn't.
Maybe I just got lucky. :D
 

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Wagon Crazy, My 350 V8 engine runs around 170 degrees on the freeway at 75 mph. It has an aluminum radiator and new Classic Auto Air, 3.70 posi, 200-4R. The transmission temp gauge reads 148-155 degrees after engine is up to max temp. It has been unseasonably cool in the SF Bay area. Temperatures have been in the low 80's with about 30% humidity, the last few weeks! WOW!
If the transmission temp rises above 175 degrees you should find out why and remedy the situation. Dextron III says the ideal transmission fluid temperature is 160 degrees.
Mine's running considerably hotter.
Engine water temp runs about 190 at freeway speeds.
Trans is plumbed into the radiator first, then to an air cooled trans cooler with 2 8" fans attached to it that kick on when the trans temp hits 180 degrees (sensor in the return line just before it comes back into the trans).

Using a digital infrared thermometer, after running the wagon hard up the freeway last week, I last measured temp at the outgoing line (to cooler) at 200 and at the pan temp was 180 degrees. When it gets that hot, it blows fliud out the overflow on top of the trans when shifting between 3rd and overdrive.

I bought this trans "used" and in supposedly good shape, but it's been doing this all along. Something makes it run hot on long runs. TC is locking up fine, and it has a brand new 1800 stall TC.

Sorry to hijack the thread, but I'm going to install the temp sender in the pan via it's own bung, and then I'll be able to get very accurate readings.

I don't know why it runs hot...when the engine is not.
 

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Wagon Crazy, are you sure you're not overfull on fluid? Normal fill is to the mark when hot with the engine running.

Seems to me that if your cooler fans kick on at 180 and you're seeing temps at 200 in the line and 180 in the pan, then everything is doing its job, and the only way you'll be cooler is to turn the fans on at a lower temp.

Chevy Chase, now that you've shared your engine temperature, it's obvious you're biased toward cool temps. Too cold for me on the engine too. Obviously you don't have a 180 degree thermostat.
 

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"Chevy Chase, now that you've shared your engine temperature, it's obvious you're biased toward cool temps. Too cold for me on the engine too. Obviously you don't have a 180 degree thermostat.[/QUOTE]"

Rick, I'm running a 165 degree thermostat. I will do whatever is necessary to keep the ATF below 165 degrees.
 
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