Installing a temp sending unit in transmission oil pan

[thermalking]

I would like to install the sending unit for my transmission temperature gauge in the oil pan of my 2005 Dodge RAM 2500 with the 5. 9L Cummings turbo-diesel but was wondering what type of brazing material people have used to braze the 3/8" brass plug fitting to the pan. Also, can I do this with a standard propane torch or would I have to have a oxy-acetylene torch. What material is the pan made of.



Thanks for any replies.



-Jay

 

[sid325]

I had my temp sensor in the pan and wasn't happy with the performance. During the winter, coming down a grade it would read zero. I ended up moving mine to the hot return line, more accurate I believe. Temps are more consistent and it has never read zero.



I got my fitting here:



DieselManor - Dodge Generation 3 Cooler Line



Just a thought.



sid

 

[ttbird]

I would like to install the sending unit for my transmission temperature gauge in the oil pan of my 2005 Dodge RAM 2500 with the 5. 9L Cummings turbo-diesel but was wondering what type of brazing material people have used to braze the 3/8" brass plug fitting to the pan. Also, can I do this with a standard propane torch or would I have to have a oxy-acetylene torch. What material is the pan made of.



Thanks for any replies.



-Jay

Propane will not be hot enough. Mapp Gas at the very least. Oxy-acetylene will braze the best. Pan, if stock, thin sheet metal, will probably need to braze a small washer to the inside then drill and tap plug into pan.

 

[p-Bar]

I am running the same as sid25 best deal going lets you know what the hottest point of the fluid is . Mine works great simple to install minor loss of fluid.

 

[rscurtis]

Why not get a sender with 1/8 pipe thread and install it into a B&M drain plug?Measuring temperature at the hot line is like trying to measure engine temperature by reading the EGT- it is load dependent as opposed to condition dependent. Let's say your hot line to the cooler shows 250 degrees- an unsafe transmission temperature for sure, but possibly normal at a particular load at that measuring location. Measuring the temperature in the pan measures the actual transmission temperature- not just a small part of it that will constantly change with the load applied.

 

[RonD]

I had mine in the discharge line when I first installed it a couple of years ago, since I have a Mag-Hytec trans pan, so I moved it to there, I feel the reading are more true now.

 

[p-Bar]

Why not get a sender with 1/8 pipe thread and install it into a B&M drain plug?Measuring temperature at the hot line is like trying to measure engine temperature by reading the EGT- it is load dependent as opposed to condition dependent. Let's say your hot line to the cooler shows 250 degrees- an unsafe transmission temperature for sure, but possibly normal at a particular load at that measuring location. Measuring the temperature in the pan measures the actual transmission temperature- not just a small part of it that will constantly change with the load applied.

I see as knowing if you are "cooking off" your fluid and then determining the lifespan of the fluid at that point. Others do agree with you though

 

[HBarlow]

I guess it's a judgement call whether you want to read temps at the hottest point in the line or in the transmission pan. If you are willing to settle for measuring in the pan Geno's sells a B&M pan drain plug for the purpose. Also, a Mag-Hytec finned aluminum cover comes with a temp gauge fitting already installed as well as a drain plug. If you tow with your truck the Mag-Hytec is a good investment.

 

[thermalking]

Thanks for the replies. Last night I removed the pan and installed a 3/8" brass fitting supplied with the sending unit from Geno's garage. I drilled and tapped the hole in the pan and then brazed it using an acid core solder I got from my local O'Reillys Automotive. The pan is made of fairly thin ~3/32 steel sheet metal which had enough thickness to get the brass fitting nice and tight. I applied some general purpose flux and soldered the joint and it looked very nice. It formed a nice fillet all the way around the brass fitting and wicked up the threads of the brass fitting as well as onto the surrounding steel plate. I know this solder has a much lower melting point than other brazing materials, but I am pretty sure that if the transmission gets hot enough to melt the solder I will have other problems to deal with. I am very happy with the way my project turned out and the temperature readings seem very stable and reliable. Driving in to work today the temperature settled out at about 155F and bobbled up and down about 5 degrees F. I forgot to mention that I installed the sending unit into the pre tapped brass fitting from Geno's using teflon tape to form a nice leak free connection.

 

[steved]

... then brazed it using an acid core solder...

Make sure you check it now and again... I've seen solder crack when used in situations like this.



Brazing would have been a better alternative, although not everyone has that capability.



FWIW, I've used both a brazed steel collar (cut in half) and B&M drain plug for temperature sender placement. The only things I would comment on is that the collar is placed inside the pan (prevents the chance of being "removed" by road debris); and that the B&M does tend to seep and requires pan removal to tighten if it loosens.

 

[merv m]

My friend does my solder work, retired air conditioning guy he uses silver solder/acetylene no problems