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Tranny Temp Sending unit location


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My sending unit is located on the upper right (top) side of the tranny above the pan. It is a Banks gauge and the instructions say the best place would be in the pan where the temp is the highest and recommends that location. The instructions also provide an alternate location for the 47RE tranny. The instructions say to locate the rear servo test port on the right rear side of the tranny and install the 1/8" NPT temp sending unit there. Mine is in neither of those locations. I was told by tranny specialist the my location was giving me a higher reading and should be relocated to the side to read the temp of the return side. He said to deduct 15 to 20 degrees from my reading. He also said the tranny temp should read lower than the engine. Comments, clarification, and direction, please.

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I had mine in the front servo port that's where my quadzilla told me to put it and I never saw a reading above 140. I didn't think that was right so I drilled a hole in the pan and welded part of a pipe fitting in there now I have seen the temperatures hit 190 sitting in traffic with no air flow going through the radiator I was glad I moved mine because now I have all of the sending unit in fluid instead of just the tip.

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After much research on subject, I have concluded that it is a matter of opinion as to the best place to locate the sending unit sensor. What I feel I gained from my research is that if your gauge is reading above 240 degrees, pull over and put the tranny in neutral and fast idle (1200 rpm) for 2 to 3 minutes to cool the fluid.

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I agree with gasser.... The number one cause of auto trans failures (aside from a right foot) is bad fluid. Fluid burns, then the trans suffers. The fluid is the hottest as it leaves the trans for the cooler, this is the only place you should watch it, anything else doesn't tell the whole story.

--- Update to the previous post...

240° in the pan is a LOT worse than 240° in the hot line. But how much worse is hard to tell, towing, empty, DD pan, rpms, etc...

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Here is something to consider on what temp. will do to the life of tranny fluid:

AUTOMATIC TRANSMISSION FLUID LIFE / TEMPERATURE RELATIONSHIP:

Automatic transmission oil can provide up to 100,000 miles of service before oxidation requires replacement, at an operating temperature of 175° F. Above this temperature, the oil oxidation rate doubles with each 20° degrees F increase in oil temperature. See chart. [TABLE]

[TR]

[TD]

DEGREES F

[/TD]

[TD=width: 156]

MILES

[/TD]

[TD=width: 156]

DEGREES F

[/TD]

[TD=width: 156]

MILES

[/TD]

[/TR]

[TR]

[TD=width: 156]

175

[/TD]

[TD=width: 156]

100,000

[/TD]

[TD=width: 156]

295

[/TD]

[TD=width: 156]

1,500

[/TD]

[/TR]

[TR]

[TD=width: 156]

195

[/TD]

[TD=width: 156]

50,000

[/TD]

[TD=width: 156]

315

[/TD]

[TD=width: 156]

750

[/TD]

[/TR]

[TR]

[TD=width: 156]

215

[/TD]

[TD=width: 156]

25,000

[/TD]

[TD=width: 156]

335

[/TD]

[TD=width: 156]

325

[/TD]

[/TR]

[TR]

[TD=width: 156]

235

[/TD]

[TD=width: 156]

12,500

[/TD]

[TD=width: 156]

355

[/TD]

[TD=width: 156]

160

[/TD]

[/TR]

[TR]

[TD=width: 156]

255

[/TD]

[TD=width: 156]

6,250

[/TD]

[TD=width: 156]

375

[/TD]

[TD=width: 156]

80

[/TD]

[/TR]

[TR]

[TD=width: 156]

275

[/TD]

[TD=width: 156]

3,125

[/TD]

[TD=width: 156]

395

[/TD]

[TD=width: 156]

40

[/TD]

[/TR]

[/TABLE]

Note: Transmission oil and filter should always be changed more frequently when driving with heavy loads (RVs), typically at least every 25,000 mile intervals, since converter outlet temperatures then normally far exceed the ideal 175° F.

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After much research on subject, I have concluded that it is a matter of opinion as to the best place to locate the sending unit sensor. What I feel I gained from my research is that if your gauge is reading above 240 degrees, pull over and put the tranny in neutral and fast idle (1200 rpm) for 2 to 3 minutes to cool the fluid.

Its not opinion when all of the major tranny shops recomend and sell the lines to monitor the temp at the converter outlet point. The reason for the aftermarket product companies telling you to put it in the pan or the servo port is because the typical everyday Joe can figure it out and can manage this simple task and they sell more parts because people think its simple enough. If most find out that it would require a line swap it would deter a lot of people wanting to add a gauge so just tell half truths and the people will buy buy buy!!!!:spend: 240* in the pan consistantly is a death wish for your tranny. I ran 2 tranny gauges at one time experimenting and I had one in the pan and servo port at the same time and they were always the same temp. I then put one in the pan and one in the converter outlet line and it was consistantly 30-40* hotter at the converter outlet port than in the pan. And as for the chart gasser posted just to add to it one has to remember that once it gets to the 300 and over range things like seals fail fast and then there is the safety issue of the oils flash point at which it becomes very flamable and when it is hot and a seal fails and sprays on a hot exhaust ect it is a real quick flame job.
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Bill, this is exactly the type info I was looking for when I did my original post. I expected a lot of replies to my post. I'm a non Motor Head but I do try to learn as much as possible as I love my truck. This forum has been a steady source of great information and my hat is off to MOPAR Man for making it happen. "Git - er - Done". I can't afford a new truck and not sure I would want anything after 2010.

Its not opinion when all of the major tranny shops recomend and sell the lines to monitor the temp at the converter outlet point. The reason for the aftermarket product companies telling you to put it in the pan or the servo port is because the typical everyday Joe can figure it out and can manage this simple task and they sell more parts because people think its simple enough. If most find out that it would require a line swap it would deter a lot of people wanting to add a gauge so just tell half truths and the people will buy buy buy!!!!:spend: 240* in the pan consistantly is a death wish for your tranny. I ran 2 tranny gauges at one time experimenting and I had one in the pan and servo port at the same time and they were always the same temp. I then put one in the pan and one in the converter outlet line and it was consistantly 30-40* hotter at the converter outlet port than in the pan. And as for the chart gasser posted just to add to it one has to remember that once it gets to the 300 and over range things like seals fail fast and then there is the safety issue of the oils flash point at which it becomes very flamable and when it is hot and a seal fails and sprays on a hot exhaust ect it is a real quick flame job.

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