transmission Temp Gauge

[tugboatphil]

I have the aux cooler behind the fuel tank, with the spider web of lines running all over the place. I have read several posts regarding placement of the temp sensor, and have heard different locations for it. So in anticipation of the torrent of abuse which may follow... . where is the RIGHT place for it?

 

[John - K5AWO]

As close to the transmission as you can get it, in the outlet line.

 

[dan brooks]

Depends on who you talk to... .



Some people want to know the temp of the fluid that is starting it's trip through the trans, so they install the sender in the pan. That also tells you how well your cooling system is working.



Personally, I want to know the max temp of the fluid, so I have my sender "T'd" off of the stock location. When the temp hits 200* I kick it out of OD or back off a bit.

 

[Cummins4Life]

Can you put the aftermarket gauge sensor in the stock OD sensor location then relocate the OD sensor to the pan?

 

[CDegner]

Originally posted by Cummins4Life

Can you put the aftermarket gauge sensor in the stock OD sensor location then relocate the OD sensor to the pan?

If you do that, you will have to remember to manually shift out of OD before your gauge gets too high. Temps in your pan should never see the 270 degrees that the temp sensor uses.



I cut into the line right were it crosses in front of the pan. eashy to do and cost about $10 in parts.



Carl

 

[dan brooks]

With the gauge, there is no reason to let the trans get to 270* - by then damage is already being done. I've actually considered just eliminating the factory sender and installing the gauge sending unit in the stock location for a cleaner install.



Never have figured out how the engineers at Dodge came up with the 270* figure... .

 

[Cummins4Life]

If you eliminate that factory sender will OD still work? I was under the impression it was needed to allow the transmission to shift into OD once a certain temperature was reached or is it only for the 270* downshift?

 

[dan brooks]

I dunno... I was just gonna tie it up out of the way with the sender still plugged in. Don't figure ambient temps will ever hit 270*, even in Arizona.

 

[CDegner]

OR, you could just measure the resitance of the sending unit and put a resistor in place of the sending unit.



Carl

 

["Mad Max"]

My readers rigs / diesel has some pics of where I plugged in my trans temp sensor. I plumbed it right inline with the outlet line - works great, as do all the other components.



With all three transmission coolers (including the aux/dealer-installed bed cooler, my transmission typically runs the same temp as the engine, maybe 10* less, unless towing when it'll run a few * hotter. Max temp I've even seen, pulling 12,000 lbs worth of trailer, up interstate 25, was about 230*, with the engine at about 220*. That was the hottest the transmission has ever registered, FWIW.



- Sam

 

[Greenleaf]

Tug,

FWIW. I put mine in the pan cause that's where the aftermarket aluminum pans are drilled and tapped for the sensor.



I suppose it would be best to have one in the outlet line AND in the pan if you were to do some serious towing..... and like to read guages.



My temp guage will not register while driving. Up hill or down. Load/no load. For the longest time I thought it didn't work. Only reads when setting in traffic, or waiting for the wife while she is in the Library. Goes to 170° then.



I change my transmission fluid about every other engine oil change. I have a service pit, so it takes no time at all.



-S



West (by God) Virginia State Motto;

No shirt, No shoes, No problem.

 

[tugboatphil]

Originally posted by Greenleaf





West (by God) Virginia State Motto;

No shirt, No shoes, No problem.

Actually, Scott, the motto is:



West Virginia, Almost Heaven for men and dogs,

Almost Hell for women and mules!





Thanks for all the input! I guess I'll just put it under the truck somewhere... .

 

[Hunter4x4]

I installed a transmission temp gauge (AutoMeter) a while back. I didn't use a 'T' on the transmission temp gauge, just swapped out the new sending unit for the factory sending unit, and zip-tied the factory sender up and out of the way. I get real good/accurate temp readings with the temp sending unit in that location.



The reason for this is simple: The only thing the PCM does with the transmission temp info (check it out in the FSM if you want to confirm!) is prevent the transmission from going into overdrive when the temp reaches +270*. 270*?!?!? If your transmission's running at 270* you're already in trouble!!!! I'll be kicking it out of overdrive manually and backing down when I start seeing temps in the 210s/220's!! Everything I've ever been taught about automatic trannys says that 240/250* is MAX (and then only for short pulls) and above that things start frying and cooking!!!!



And my OD works perfectly!!!

 

[dan brooks]

Thanks - that confirms my thoughts on the factory sending unit. My under bed cooler was delivered today, so I'll take care of it all this weekend.

 

[Greenleaf]

I have read somewhere's that the 'puter will sense the transmission fluid temp. and prevent a 3rd to OD upshift when the oil is BELOW a set point. I have driven in cold temps and never had the transmission hold 3rd.



Just thought I'd throw that out. Makes no difference anyhow. We ain't worried about too cold of oil 'round these 48 states.



-S

 

[dan brooks]

I've read that, too, but have never had mine fail to shift into OD, even when it was very cold. If it becomes a problem I'll use a resistor.