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#2370117 - 09/13/17 01:34 PM 46RE hit 260F in 2003 CTD - cooling suggestions?
Tom_440 Offline


Registered: 03/05/03
Posts: 4943
Loc: Las Vegas, NV
While hauling about 9k, the trans temp climbed to 260 this weekend. I'm replacing the original trans cooler with a factory replacement as the internal thermostat may (or may not) be stuck. Looks like the factory coolers are fairly stout. Deep trans pans don't seem to directly help keep the trans fluid cooler. Is there anything else I should be looking at to keep the fluid cooler? Thank-you!

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#2370262 - 09/13/17 04:47 PM Re: 46RE hit 260F in 2003 CTD - cooling suggestions? [Re: Tom_440]
Dave Hall Offline
super stock

Registered: 01/21/08
Posts: 949
Loc: Cotati, CA
260 isn't totally terrible and I'm sure it was knocked down to engine temp. when you got off the hill or were able to power down for a bit. You should expect it to go over 210 when towing on the pipe. I have an ATS deep pan on mine and the factory cooler setup. The cast pan is super heavy and kind of a biotch to change the filter. Make sure the fan clutch is working, the elevated trans. temp will kick the fan on. Turn the key on and off three times leaving it in the on position (no start) and see if you see P0386 come up. That is the fan clutch code and won't always trigger a check light.

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#2370283 - 09/13/17 05:28 PM Re: 46RE hit 260F in 2003 CTD - cooling suggestions? [Re: Tom_440]
Transman Offline
enthusiast

Registered: 03/27/11
Posts: 399
Loc: Michigan
What was your engine temp when you saw 260 on the trans. Where is your trans temp being registered - sump, cooler line, ?

The CTD has two coolers. One on the engine ( driver side above bell ) and another at the cooling module.

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#2370532 - 09/14/17 01:44 AM Re: 46RE hit 260F in 2003 CTD - cooling suggestions? [Re: Transman]
Tom_440 Offline


Registered: 03/05/03
Posts: 4943
Loc: Las Vegas, NV
The engine temp was about 210. I was reading the temp from an Edge gauge plugged into the OBD II port so I believe its reading the temp from the factory temperature/pressure sensor.

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#2370537 - 09/14/17 02:15 AM Re: 46RE hit 260F in 2003 CTD - cooling suggestions? [Re: Tom_440]
Cab_Burge Online   content
Too Many Posts

Registered: 08/23/03
Posts: 29210
Loc: Bend,OR USA
Most American made petroleum based ATF has a dye in it that will start to change colors from red to brown at 275F, and go to black at 325 F scope
What colors is your fluid on the stick now?
If your running pure synthetic based ATF it won't start to be hurt until above 500 F shruggy
I use to see around 230 F on my 1998 1/2 Ram 2500 CTD pulling the Baker grade in August in the afternoon going to the drag strip in L.V. at 70 MPH kicked out of O.D. running the air conditioner pulling my 24 Ft Pace Shadow enclosed race trailer with the car and other goodies in it. That trailer weighed right at 9200 Lbs. disconnected from the truck on a certified CA state scale with my 3200 Lb race car in itshruggy
My trans .temp sending unit was in the front servo where the CTD registry recommends using them shruggy I had it in the bottom left front corner of the trans pan originally and I didn't see any difference in the temperature moving the sender up into the front servo port access plug hole shruggy confused That truck used the ATF+3 fluid in it. Around town in the summer or winter running empty it would never get above 140F no matter how hard I drove it confused It did have the factory towing package on it also. When ever I hooked up the race trailer to it the trans temps. went up to 180 empty or full towing on the flats shruggy
My main message is if your trans. fluid color and smell is okay your probably okay up twocents


Edited by Cab_Burge (09/14/17 02:20 AM)
_________________________
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#2370609 - 09/14/17 09:36 AM Re: 46RE hit 260F in 2003 CTD - cooling suggestions? [Re: Tom_440]
crlush Offline
super stock

Registered: 04/11/05
Posts: 1068
Loc: Michigan
Bypass the water coolant in the trans oil cooler mounted to the back of the motor

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#2370666 - 09/14/17 10:54 AM Re: 46RE hit 260F in 2003 CTD - cooling suggestions? [Re: Tom_440]
Transman Offline
enthusiast

Registered: 03/27/11
Posts: 399
Loc: Michigan
You can bypass the heat exchanger on the engine as a test and see what it gets you for temps. It's the first one to see debris. Most people don't even know this heat exchanger exists and replace the front cooler module.

The other possibility is the anti-draindown valve ( check valve ) got stuck. We have seen those do that before. I think the CTD has two valves.

Other possibility is you ran with the converter unlocked for some reason. That will spike the temps real quick especially if you are bucking a lot of wind.

Purpose of the heat exchanger - it gets the trans fluid temps up to operating temperatures faster in cold weather ( you don't live there ) and provides some fuel economy and better lubrication. At most in your situation - you raised the fluid temp to 210 then the cooling module lowered it before returning it to the trans.

A plugged or restricted cooler remains so - if the unit runs cool now you may just want to watch things.

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#2370679 - 09/14/17 11:17 AM Re: 46RE hit 260F in 2003 CTD - cooling suggestions? [Re: Tom_440]
RapidRobert Offline
Circle Track

Registered: 11/20/03
Posts: 32405
Loc: Lincoln Nebraska
Quote:
While hauling about 9k, the trans temp climbed to 260 this weekend. Is there anything else I should be looking at to keep the fluid cooler?
260 sure seems high to me. I would keep it simple & add some extra coolers in the line in series exposed to good airflow
_________________________
live every 24 hour block of time like it's your last day on earth

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#2370689 - 09/14/17 11:30 AM Re: 46RE hit 260F in 2003 CTD - cooling suggestions? [Re: Tom_440]
Transman Offline
enthusiast

Registered: 03/27/11
Posts: 399
Loc: Michigan
Yep - keep it simple - add more coolers.

The factory cooler package is good for way more this you are hauling.

You either had a one time event or you have something else going on.

Adding coolers is premature and the typical knee jerk reaction.
A good tech will diagnose before throwing parts at it.

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#2370908 - 09/14/17 06:12 PM Re: 46RE hit 260F in 2003 CTD - cooling suggestions? [Re: Tom_440]
HotRodDave Offline
master

Registered: 01/29/05
Posts: 9401
Loc: Kalispell Mt.
the trans temp sensor is built into the gov pressure sensor so it was actually the temp INSIDE the trans not just a temp in the cooler line somewhere. I would not be happy with those temps. Check to see if you can blow air through bothe coolers and the lines, also check lock up.
_________________________
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68 cuda 360 notchback SOLD

1996 Ram 2500 5.9 eddy intake EQ heads, mild cam upgrade great tow rig!


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#2370914 - 09/14/17 06:35 PM Re: 46RE hit 260F in 2003 CTD - cooling suggestions? [Re: Tom_440]
Transman Offline
enthusiast

Registered: 03/27/11
Posts: 399
Loc: Michigan
Unless you blow air the correct direction you'll get no flow. If you want to test the inegrity of the cooler system do a flow test. There are other things that could contribute to poor flow if that is what you think is your problem.

Remove the rear cooler line at the trans and place in a clear plastic jug - like a clean empty washer solvent jug. Have someone start the engine and place in neutral. As soon as it starts flowing run it for 10 seconds then shut the engine off. A normal 1/2" system at 70F will pump no less than a quart in that 10 seconds. That tests the draindown valves, coolers and lines, valve body converter circuit and pump.

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#2371291 - 09/15/17 02:43 PM Re: 46RE hit 260F in 2003 CTD - cooling suggestions? [Re: Tom_440]
J_BODY Offline
I Live Here

Registered: 04/30/03
Posts: 11021
Loc: aZLiViN
2003 early build CTD will have a 47RE, later builds with the HO engine will have the 48RE trans... either way, if you are seeing that temp while towing, you've got problems either electrical or mechanical. You didn't state at what speed you were experiencing this. In a "normal" state the only way I could see this trans achieving those temps is if you were climbing somewhere at a slow speed and torque converter lock up could not be achieved. My race trailer weighs in at the 9-10K range and towing down the road lockup achieved will run in the 150 range. This is on my 01, but any CTD with the RE trans I've seen similar results.

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#2372050 - 09/17/17 12:47 AM Re: 46RE hit 260F in 2003 CTD - cooling suggestions? [Re: J_BODY]
Tom_440 Offline


Registered: 03/05/03
Posts: 4943
Loc: Las Vegas, NV
Thank-you all for the help!

The truck had a code "P0633 SKIM Key Not Programmed in PCM" Not related and a non issue.

The trans fluid is still red, but I'm changing it anyway.

I drove from CA up the grade to Victorville and then up the Baker grade and it didn't get hot like this. Then when I was in Vegas, the road was much flatter. There was a wind and that's when it got real hot.

The truck is a early 2003 build, not the HO. I replaced the front cooler with another OEM cooler because its 14 years old and I'm not sure the thermostat in it was working. Those tranny lines are a pain to disconnect from the cooler. Flow test is next...

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#2372154 - 09/17/17 10:59 AM Re: 46RE hit 260F in 2003 CTD - cooling suggestions? [Re: Tom_440]
J_BODY Offline
I Live Here

Registered: 04/30/03
Posts: 11021
Loc: aZLiViN
Did the trans temp light come on? believe they come on at 260 and will stay illuminated until the temp drops below 220. this also is accompanied by loss of OD as the program wants 3rd lockup in order to help cool the trans. skim key code.... see that in a lot of them. no worries. I'm pretty sure your truck doesn't have the thermo block to redirect fluid flow, but just the one way check valve to prevent drain back. That would be in the line near the heat exchanger on the drivers/side/rear engine block. I drilled mine out years ago as I'm not a fan of anything in line that could restrict flow. When you were towing "in vegas" was that at freeway speeds? or crawling through traffic? In my mind this could probably be a erroneous output from the gov psi transducer which also contains the temp sensor. Would have been interesting to see how quickly it occurred.

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#2372225 - 09/17/17 12:57 PM Re: 46RE hit 260F in 2003 CTD - cooling suggestions? [Re: Tom_440]
Transman Offline
enthusiast

Registered: 03/27/11
Posts: 399
Loc: Michigan
The governor transducer and governor solenoid are independent of the thermistor. The thermistor is part of the harness for both the solenoid and transducer - that's all.

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#2372370 - 09/17/17 06:40 PM Re: 46RE hit 260F in 2003 CTD - cooling suggestions? [Re: Transman]
J_BODY Offline
I Live Here

Registered: 04/30/03
Posts: 11021
Loc: aZLiViN
Originally Posted By Transman
The governor transducer and governor solenoid are independent of the thermistor. The thermistor is part of the harness for both the solenoid and transducer - that's all.


no.... pretty dang sure that isn't all.

DESCRIPTION

Transmission fluid temperature readings are supplied to the transmission control module by the thermistor. The temperature readings are used to control engagement of the fourth gear overdrive clutch, the converter clutch, and governor pressure. Normal resistance value for the thermistor at room temperature is approximately 2000 ohms.

The thermistor is part of the governor pressure sensor assembly (2)(Governor Pressure Sensor) and is immersed in transmission fluid at all times.

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#2372392 - 09/17/17 07:45 PM Re: 46RE hit 260F in 2003 CTD - cooling suggestions? [Re: Tom_440]
Transman Offline
enthusiast

Registered: 03/27/11
Posts: 399
Loc: Michigan
I had the evolution backwards - we launched with a loose thermistor then incorporated it in the transducer.

As for the logic and why it is there - you ar correct - we use the readings as part of an alogorithem. The resistance was 1k or 2k depending on the year - the change came around 2000 MY. The same basic logic is used in the 41TE, 62TE, RFE family to more precisely control functions based on temperature.

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#2372474 - 09/17/17 10:50 PM Re: 46RE hit 260F in 2003 CTD - cooling suggestions? [Re: Tom_440]
J_BODY Offline
I Live Here

Registered: 04/30/03
Posts: 11021
Loc: aZLiViN
whew!!.... laugh2 either way, that truck pulling a 9k trailer in Vegas (no real grades) should not see that temp, not even on the hottest of summer days... no where close. Which brings to mind OP.... what does the harness look like going into the trans? Many of them leak and eventually turn the wiring insulation into jello which can result in contact between circuits. Just one of a many of possibilities. I tend to think this may be more of an electrical issue. Odds are that if you had something "going away" it would have reared it's ugly head on the Cajon or Baker grade. Please let us know what you find Tom

J

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#2372548 - 09/18/17 02:00 AM Re: 46RE hit 260F in 2003 CTD - cooling suggestions? [Re: J_BODY]
Tom_440 Offline


Registered: 03/05/03
Posts: 4943
Loc: Las Vegas, NV
You guys are far above my knowledge level and I truly appreciate the help. I was on the freeway in Vegas at about 60 mph when the temp went up. I don't recall an idiot light but the OD did shut down. I hit a downhill grade and the trans cooled down and OD came back on. The serpentine belt rubbed a hole in the AC hose which killed the AC a little before the temp went up, but I don't see how that would be related. I'll look for the check ball, plugged lines, check the harness, flow test and swap the trans filter this week or weekend and report back.

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#2372559 - 09/18/17 05:21 AM Re: 46RE hit 260F in 2003 CTD - cooling suggestions? [Re: Tom_440]
Dave Hall Offline
super stock

Registered: 01/21/08
Posts: 949
Loc: Cotati, CA
Ok, the belt thing is some info that was not previously provided. Could it be that the fan wasn't doing it's job???

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