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Cooling system not able to keep up


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On the final leg of my journey to our campsite while towing my travel trailer the engine temperature climbed up to about 220. The mark between 190 and 240 on the dash gauge. We were on a paved road, so no low range 4x4 was utilized. The grade was very steep and I was in second gear at about 2,000 RPM's. When I got to the top the temp reading for the engine was about 220. Smelled hot too. No gauges to monitor EGT's, etc so I cannot comment on that. So I put the truck in neutral and ran up the RPM's to about 1,500 until it came back to normal operating temp. Is this typical or should I be looking for an issue?

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Check the fins in the radiator for clogging also. If you have the oe puke bottle up front you will have some clogging and that will also cause higher temps. It is difficult to see the clogging. A mirror would be your best bet. I never could see mine clogging until I took it out. EGT gauge is very good thing to have as John states.

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Here are a couple of pictures of mine. I always felt I was somewhat immune to the puke bottle thing since my truck has spent 99% of the time on highways. The other 1% has been on reasonably level ground though in the dirt. I looked at the radiator many times looking for build up and never noticed it was there due to the difficulty of seeing it. When looking over the top of the radiator the fins are still visible and it is the clogging you cant see. That is why I suggested the mirror.post-10340-138698203235_thumb.jpg

post-10340-138698203227_thumb.jpg

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Most likely what caused your temp to come up was prolonged driving in 2nd gear. The 47 has no lock up in the low gears and will shoot your trans temp skywards which will eventually raise coolant temp as well. I would be more concerned with how hot your trans got on that climb

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Most likely what caused your temp to come up was prolonged driving in 2nd gear. The 47 has no lock up in the low gears and will shoot your trans temp skywards which will eventually raise coolant temp as well. I would be more concerned with how hot your trans got on that climb

Pretty sure the internal dash transmission temp light would have triggered in that case. Think it's around 240 degrees .... Can't remember exactly... But Another good guage to have
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Pretty sure the internal dash transmission temp light would have triggered in that case. Think it's around 240 degrees .... Can't remember exactly... But Another good guage to have

According to the Dodge FSM the trans temp light doesn't come on till 265*F...
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Opps! I goofed... :doh:

From the Dodge FSM book.

Trans Over-Temp Lamp-On Message - Each

time the cluster receives a trans over-temp lamp-on

message from the PCM indicating that the transmis-

sion fluid temperature is 135° C (275° F) or higher,

the indicator will be illuminated and a single chime

tone is sounded. The lamp remains illuminated until

the cluster receives a trans over-temp lamp-off mes-

sage from the PCM, or until the ignition switch is

turned to the Off position, whichever occurs first.

The chime tone feature will only repeat during the

same ignition cycle if the transmission over-tempera-

ture indicator is cycled off and then on again by the

appropriate trans over-temp messages from the PCM.

At that point the transmission is well done... Next please... :duh:
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Most likely what caused your temp to come up was prolonged driving in 2nd gear. The 47 has no lock up in the low gears and will shoot your trans temp skywards which will eventually raise coolant temp as well. I would be more concerned with how hot your trans got on that climb

I agree.

At that point the transmission is well done... Next please... :duh:

Yeah more of a "new trans" light than a caution. Its very hard to produce enough heat (coolant or EGT) at slow speeds in the engine to overload the cooling system, which means 1 of 3 things (or a combo). As already mentioned the trans is most likely the culprit, as is some radiator blockage, but the fan clutch could also be bad. Gauges are great, but I doubt they would have showed anything abnormal here. If the motor is stock I wouldn't overly worry about it, unless you want to. The BHAF is the only thing I see that could so anything negative at slow speeds, and even then that is a stretch.
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Just to clearify. I was towing 7,000#, going uphill on a paved road that was much steeper than typical roads. Like a 40 degree angle road. Was going uphill for 5 total miles in second gear. I'd of been using low range if I had the Posi Trak conversion made for 2 wheel drive low range. But being paved I didn't. Last leg of steep road was maybe a mile. Fan clutch works fine. No problems with overheating on hiway roads which were 55 mph roads.

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A 40° road would be a 88% grade, and the steepest roads in the US are around 30%, or 13.5°. What road were you on?If you fan works then I would verify the radiator is clean, and possibly a clean/flush on it. Does the 47RE not lockup in 2nd if you put the selector in 2nd?

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We go fourwheeling in West Virginia every spring and the road coming into one of the camps we have stayed at is similar to what you describe. Very steep sections of switchback gravel road with occasional washouts. I do use low range as 4wheel drive is required due to the steepness of the grade, lack of traction and dragging a trailer up it.I don't think the truck would make it the entire way up in hi range it would be very hard on it and probably overheat. Keep in mind my top speed is never over 10 mph and by the time I get to the top I have seen temps of around 210 or so. I don't think you have anything to worry about as long as your radiator is clean and like AH said gauges are not real important ona stock truck but they are a good peace of mind

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Does the 47RE not lockup in 2nd if you put the selector in 2nd?

Unfortunately it does not

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That's why I want to do the posi-trak manual front axle engagement modification. When on hardball that's steep I would prefer low range 2 wheel drive. Plus will make 3 point turns on gravel roads easier. No front end hop and stress on front axle components.

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Logging road in BLM and industrial forest.

Where about? There are places online you can look at the grade.

A 40% grade is steeper than any street (implies paved) in the US that I can find, but a 40° slope is very different.

We go fourwheeling in West Virginia every spring and the road coming into one of the camps we have stayed at is similar to what you describe. Very steep sections of switchback gravel road with occasional washouts. I do use low range as 4wheel drive is required due to the steepness of the grade, lack of traction and dragging a trailer up it.I don't think the truck would make it the entire way up in hi range it would be very hard on it and probably overheat. Keep in mind my top speed is never over 10 mph and by the time I get to the top I have seen temps of around 210 or so. I don't think you have anything to worry about as long as your radiator is clean and like AH said gauges are not real important ona stock truck but they are a good peace of mind

Yeah, I have camped on some steep dirt and paved area's. The steepest pavement I have towed on, or that I have looked up, is in the 20% slope range. I have hit sections much steeper than that on dirt.

This past weekend I was towing (17.5K GCW) up a section of switchbacks with an area of 20% +.

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Unfortunately it does not

Bummer!

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That's why I want to do the posi-trak manual front axle engagement modification. When on hardball that's steep I would prefer low range 2 wheel drive. Plus will make 3 point turns on gravel roads easier. No front end hop and stress on front axle components.

I just put hubs on my truck this spring and it's much nicer having a rig with 2 Lo again.

I also want a full time xcase, but that's another thread.

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