Engine/Transmission (1994 - 1998) Installing Trans Temp Guage

[danadj2]

On the 47RH trans are there different places to put the sending unit. If so, which are considered the most effective placements?

 

[Joe G.]

The most effective place is there the stock temp sensor is for the OD. I put a 700 ohm resister in the stock cable to the temp sensor. Then I replaced the stock sensor with one for my new gauge. The resister fakes out the OD control so it always gets a warm transmission signal and you have OD. This sensor is only on a 47RH so I don't think it is necessary.

 

[TJarecke]

Get a trans line from Mass Diesel. That is what I did. Easy install no guessing. Worked for me.

 

[danadj2]

I ended up using a pressure port on the passenger side of the trans. Temps are running at 150-160 in normal no-load driving.

 

[sfelts]

I had instaled a hytech oil pan and it came with a pre driled and taped hole for a sencer.

 

[budctdca]

here is where I have been putting them

 

[Joe G.]

That's not a good place. The only time there is oil flow at that test point is in 2nd gear. The line pressure test point is much better. Some temp sensors won't fit in a 47RE in the line pressure test point. It's not as deep as the 47RH. The best place for the sensor is the hot (forward) cooler line. The line pressure test point is good too.

 

[budctdca]

if the oil is only there in 2nd gear, why does the temp stay warm when you are cruising the highway in OD for a long time? and the temp certainly does reflect the load on the transmission.

 

[Joe G.]

Since there is no or little flow there in other gears it will not reflect temp change accurately. I got this from reading Bill K's responses to questions posted on the forum on his DTT web site. In fact I had mine at that location at one time and moved it to the line port after reading his comments. After moving it I noticed that temp readings did change quicker at the line port than the front servo test port. He also says the front cooler line is the proper place for a temp sensor. That's where mine is now.

 

[danadj2]

I'm looking at all this but not smart enough to comment yet. This is some good stuff though.

 

[budctdca]

Maybe the line is the optimum place to put it, but I have noticed direct correlation of my transmission temp to ambient air temperature, changes in the way I drive, and also what kind of load I have. Even with a small load, like an empty trailer, I see elevated temperature, and appropriately I see even higher temps when I have a full load on. So to say that this placement is not a good place would be stretching it, but I do agree there might be a better place for it, ie. the front cooler line. I haven't blown my STOCK transmission yet!

Luke

 

[MikeC]

Test port.

Joe

Where is the line pressure test port.

Thanks

Mike

 

[Joe G.]

Mike,



In my 47RH trans there is a test port on the front and rear servos. In between them on the main case is another 1/8" NPT pipe plug. That is the line test port. I think the 47RE if that is what you have is similar.



Dan,



I'm just going by what the expert says about location. In fact, he gets kind of sarcastic about puting it in the front servo. According to him it does not reflect the proper temp at that location. As I said before, after I moved mine it seemed to change quicker for different conditions. It did change at the front servo alright, but was it correct? I can't tell for sure so I take the word of an expert.

 

[PKemp]

Joe G.

I also had the guys from Suncoast Converters tell me that the best place was were the stock temp sensor is. I am about to do that but tell me: what wattage is that 700 ohm resistor? 1/4, 1/2, ???

They did also say that the OD temp sensor was fairly useless and could be cheated like you describe.

 

[Joe G.]

A 1K resistor will work too. The one I used was a 1/2 watt. Very little current so I think a 1/4 watt would be ok. The 1/2 watt resister is a little tougher physically of course and the wires are a little bigger for better contact in the connector. I thought I would start with a 700 and see if that worked. It did so I quit experimenting.

 

[Andy Redmond]

Listen to Joe, he knows his stuff. He's telling you where a warmer reading might be (cooler line).



The 95's (likely the 94's too) had this external temp sender, which can be tee'd to allow for the oem unit and the aux sensor for your trans temp gauge(94-95 the 47rh trans)



Many will retrofit the older line to the trucks (96-02) with the 47RE's, which have the temp sensor inside the pan/valve body.



Here's the DC number for the 95 cooler line with the plugged port (bush it down and install your sensor for the aux gauge).



05011244AA Trans. return line updated (95 style line) $100+/-

52028764AA Trans return line (brass adapater hose to trans) 30+/-





Good luck

Andy

 

[JFaughn]

On mine I got the brass fittings to put a tee were the orignal sensor is , I think thats about as close as I can get to having my cake and eating it too .

 

[danadj2]

This is where I ended up with my sensor. It is slow to come up but seems to run at around 150 degrees. I haven't had it under a load since I've put the guage on so not sure what to expect. BTW, this is the second rebuild at 205k mi. and when we had it down, there was no sign of overheating just wear on the bands from what I believe was a faulty valve in the valve body assembly early on after the first rebuild some 65k mi. ago. After repeated trips to the shop the sluggish nature of the truck went away when the valve body was changed out and they admitted they were wrong but I believe the damage had been done.