Trans temp sensor location

tonybolton · Jun 13, 2016

So after yesterdays heat wave ride, I have some questions and concerns.

Stats:
1998 5.7 Vortec motor
mid 80's TF727 auto trans rebuilt 3 months ago with a reverse manual valve body....very firm shifts, new / stock torque converter. (odd combo I know, it uses some big adapter plate)
1 ton axles
43's
4.88's with 4.3 atlas
YJ Juggy

I only recently installed a trans temp gauge and have been on about 4 rides with it. Temp gauge seemed to stay around 200-210 most of the time. This was with a random 11x8 "zip tied to the radiator" trans cooler. Engine temps stay in the 190-210 range. This was when the weather was in the 70's-80's. I'm also using a Taurus fan for engine cooling.

Wanting to lower temps a lil more, I opted for a stand alone trans cooler with a fan. It's about 10x8 with an 8" fan on It, and I mounted it just forward of the fire wall on some of the tubing with the fan visible from outside blowing into the cooler towards the engine. Hood has LOTS of holes cut in it for ventilation. Plenty of air behind the cooler and plenty after(blows sorta at the brake booster)

I did a lot of trail riding yesterday on the first outing with the new cooler and wasn't happy. A lot of these trails were on long drawn out hill climbs but I want to say I was in 2wheel low, using 2nd and 3rd gear 90% of the time, RPM's in the 1500-2500 range. Granted, it was most likely 100+ degrees or more but my trans temp gauge would just peg at 250 and sit there(engine temps stayed at 210-215ish). No change at all in the trans shifts and the fluid is still nice and red.

We'd get to shady / rest spot and I would let the rig idle with the hood up for about 5 minutes and the trans temp would go down to 210-220. The fan on the trans cooler is wired up as key-on for now, no thermo-switch.

I obviously know that trans temps over 200 are kinda nice to avoid, but I'm wondering if I'm getting an accurate reading of the actual temperature? I have the sensor located in the rear most actuator? servo? ....whatever that things called, test port. It had a 1/8 npt plug in it. I searched the 727 trans a bit for this location and found that this was where Dodge installed their factor temp sensors from the factory.

My next step is to install the sensor just AFTER the cooler to see if that reads any different. Anyone have any feedback or advice on something like this?

Mortalis5509 · Jun 13, 2016

Re:

I have read to put it in the pan. So I have a place in the pan for a bung. Not running, so no actual feedback.

I wonder where newer diesels pull temps from. My 08 f250 has a tuner that gives the exact degree for the trans.

tonybolton · Jun 13, 2016

Yea, the pan is where most temp guage install instructions say, but I reaaaaaaaaaaally don't wanna drop the pan/loose the fluid to do that.

Was doing some Googe-ing and some say that when the trans is NOT in 1st gear, the first gear servo/actuator gets no circulation. Might explain why my temps were so high since most of my riding was in 2nd/3rd?

I did use 1st gear some, but it was for semi-short traveling in 2hi. I don't recall the temp dropping down much except for when I was going downhill for an extended time in said gear. I attributed the temp drop to "non use".

But....it's the internet and I can't tell an expert from billy bob bolt stripper. ****sigh****

Just for shits and giggles, I monitored the trans temp on my tow rig 2008 5.3 1500 on the tow home. I leave the trans in 3rd gear and haul ass with it wherever I go......it never saw above 190F until I'd get to the one nut kicker hill before my house. It's a good incline with a stop light at the bottom. I keep it in 2nd and will sometimes even shift DOWN to 1st(it's a brutal hill for the 5.3 at like 30-35mph). At the top of this hill, I saw 205 on the trans temp gauge. I figured if that made that hit 205, then that was about as hot as it's gonna get. Kinda worries on me on the 250 my 727 saw all day.

Boz · Jun 13, 2016

The pan is prefered but, if not the pan I would use the main line pressure port. I have used the main line pressure ports on many other transmission makes and had good success. I don't llike post cooler temp gauge mounted sending units. I want to know how hot the transmission actually is, not how cool the fluid is coming from the cooler.

The hotter your trans is the better the radiator style fluid to fluid heat exchanger works. Once your trans gets over say about 225 degrees it is hard for an air to fluid type exchanger to catch up. I prefer a trans cooling system that routes the hot trans fluid from the trans to the radiator then to a external cooler , before returning to the trans. I realize this isn't always possible. I am just speaking from my experience.

Mortalis, Newer diesel transmissions and some older units too as well as gassers, have a temp sensor built into the wiring harness or mounted on the valve body. The PCM/TCM reads it and uses that info in the shift strategy or to illuminate a dummy light. That info is viewable on a scaan tool, a programmer display, and on some rigs as a actually gauge.

June dog · Jun 13, 2016

Not sure about the trans, but I'm glad to know that someone else's old school motor runs around 200 and above. This is one reason I don't like to ride in the summer time. Hope you get your trans figured out.. I was always told they should stay about the same temp as the engine. Their reason for that was, on a regular car / truck the trans cooler hooks up to the radiator tank. Or they do on older stuff. So kinda makes since. :dunno:

pholmann · Jun 13, 2016

Your money ahead if you have the room to run a derale cooling pan. Plus it has a port for a trans temp gauge.

http://www.ebay.com/itm/Derale-14210-Dodge-A518-A727-Transmission-Cooling-Pan-/381277561791?hash=item58c5e9e3bf:g:C2EAAOSwd0BVu69x&vxp=mtr

tonybolton · Jun 13, 2016

Re:

I thought about a finned pan that'd hold another quart or so....but I really don't wanna loose any ground clearance.

kushKrawlin · Jun 13, 2016

Fuk a temp guage Tony. Run a cooler with a fan in area where it sucking 200° heat, and Rock out. I had a temp guage. Pffff what an ordeal. Maybe if the pan has a bung already .. But you better be careful where you put tha bung if u decide to do the pan. Yep I fuked mine up doing that ****. Got a new pan , and mounted be cooler under the seat like I think you said you had yours ... Not one prob since.... Other than that I honestly think it is impossible to put a pan on Without it leaking. Horse **** I tell ya!

1tonrenegade · Jun 13, 2016

Remove auto then install 4 speed an drive on :****:

kushKrawlin · Jun 13, 2016

Hahaha.

tonybolton · Jun 13, 2016

Re: Re: Trans temp sensor location

1tonrenegade said:
Remove auto then install 4 speed an drive on :****:

3 pedals are gay. 8)

tonybolton · Jun 13, 2016

Re: Re: Trans temp sensor location

kushKrawlin said:
Fuk a temp guage Tony. Run a cooler with a fan in area where it sucking 200° heat, and Rock out. I had a temp guage. Pffff what an ordeal. Maybe if the pan has a bung already .. But you better be careful where you put tha bung if u decide to do the pan. Yep I fuked mine up doing that ****. Got a new pan , and mounted be cooler under the seat like I think you said you had yours ... Not one prob since.... Other than that I honestly think it is impossible to put a pan on Without it leaking. Horse **** I tell ya!

This one's doin ok....before I had it rebuilt it seeped good and all the pan bolts were usually wet. I was told the same thing about always leaking though. I'm pretty happy with the rebuild.

onepieceatatime · Jun 13, 2016

Re: Re: Re: Trans temp sensor location

tonybolton said:
3 pedals are gay. 8)

Might as well cut a hole in the floor and Fred Flintstone it with an old dinosaur hand shaker transmission.

Sent from my SM-G930T using Tapatalk

1tonrenegade · Jun 13, 2016

Re: Re: Trans temp sensor location

tonybolton said:
3 pedals are gay. 8)

So is complaining about the temp! :stir:

tonybolton · Jun 13, 2016

Well...it's a DODGE piece....prolly can't handle that chevy woopow that's bolted to it. 8)

half ton · Jun 13, 2016

I know this is a lot of extra work but if it where me I would read temp at inlet line and outlet. Best way to know what is going on, but as hot as it was weather wise you may just need to move cooler and fan out of engine bay.

tonybolton · Jun 13, 2016

Re: Re: Trans temp sensor location

half ton said:
I know this is a lot of extra work but if it where me I would read temp at inlet line and outlet. Best way to know what is going on, but as hot as it was weather wise you may just need to move cooler and fan out of engine bay.

Yea....I'm afraid so. That was the original plan anyway, but I couldn't commit to a safe place near the back of the rig.

I may move it to temporary spot out in the open for a ride and jus see if it changes before making it permanent.

jeeppoor · Jun 13, 2016

I plan on doing installing trans temp gauges this winter.
One on the pressure line right as it comes out of the trans and one on the return right before it goes into the trans. That way I can monitor what the temp the oil is coming out of the trans and what the temp of the oil is going into the trans.
Also plan on putting a fan on the oil cooler that is hook up to the return line.
Right now the trans fluid runs through the radiator then to a oil cooler then back to the trans.
No problem so far.
Motor runs between 190 to 210. With is ok for a 4.0

e4cutler · Jun 13, 2016

I put an inline temp gauge on mine on the line coming out of the pan and into the cooler which sits in front of the radiator. Mine runs way to hot as well. Got upwards of 220 - 230 at Hidden Falls a couple weeks ago. I'm planning on putting a oil cooler with fan and hopefully that will fix the problem. I'm like you though, not sure where to put it.

half ton · Jun 13, 2016

Trans temps should run between 190&210. Something I found out a while back is that the fluid in the torque converter can get as high as 350-400 degrees....just a little tid bit of info.