Engine/Transmission (1998.5 - 2002) Dodge engine overheating, Colorado mountains

[groser]

Dodge, Year 2001, 3500, AT with 4. 10 rear end. 35,000 miles. 4 WD. When towing 5th wheel on long grades I sometimes overheat. Dealer replaced thermostat, no help. Overheating even occurs when outside temp around 58 Degrees. I'm towing between max rated load (20,000 lbs gross) and occasionaly 10% over rated load. Problem seems to occur only when above 7,000 feet. Any ideas on cause. Dealer stumped but has not attached scan tool and says it won't help. Power seems adequate and engine runs fine.

Can anyone tell me how the fan clutch works. I got two different stories from dealer. At times when engine temperature starts climbing I hear a roaring noise from engine compartment that sounds like a fan speeding up and sometimes I see engine temp begin to drop, then noise decreases. One mechanic thinks it's torque converter noise. Fan clutch seems tight and stops spinning immediately at engine shutdown.



Any devices out there that would allow me to lock my Automatic transmission in any gear I want. ? Forced to downshift to 2 nd gear on steep hills because transmission shifts violently between 3rd and 2nd.

When I take transmission out of overdrive is that same as locking up torque convertor? Obviously I'm lacking in automatic transmission technology!!

 

[slavallee]

The way I understand it, the fan clutch is activated by a viscus (sp?) fluid that when heated, will expand to engage the fan clutch and viola!, your fan spins. Creating an awful racket I'm told. Your notice of this being a problem at altitude may be a factor of atmospheric pressure being less above 7000 ft and it making some difference on when the fluid expands enough to engage the fan clutch. I'd put my money on your fan clutch as being the source of your overheating woes, replace it, it won't make things any worse. And BTW, I don't believe the fan clutch would even be diagnosable by any computer or code scanner, pretty sure its a "it works, or it don't" deal.



As for the transmission question, it's beyond me. I've read up on auto trannys and have officially declared them to be "the work of the devil" and have vowed never to own one if I could help it.



Hope I helped with the overheating problem.



Dr. Science,

Scott

 

[FL70CAT]

Did you replace the t-stst with a 180degree unit or did you use the junky stock high temp unit??



Your viscous fan clutch might need replaced as well.





Do you have a boost gauge?? Maybe boost is low and causing high egt's????

 

[fest3er]

If you are hearing a loud roar under the hood when the engine is worked hard, then it's the fan spinning up. But if it shuts off too quick, the clutch maynot be functioning right. At others suggested, the clutch might need replacing, though they *should* last longer than 35K miles.

I had a similar problem with mine. Cummins Atlantic put it on the dyno and found internal temps were above 230F. They replaced the t-stat and suggested I might need a fan clutch and/or a new radiator. I opted to put in a clutch, as I hadn't heard the fan run in a *long* time. I never see the temp gauge reach 190 any more.

As to the trans, when you shift out of OD, you are shifting into 3rd (or direct). As long as the go pedal is 'off idle' the TC clutch will engage.

The source of your 'violent' shift into 2nd *could* be that you are downshifting from OD into 2nd, skipping 3rd completely, which could seem 'violent'. You're better off shifting out of OD first, then dropping to 2nd. It'll be smoother.

Fest3er

 

[cwsoules]

To get improved control of your transmission chreck out dieseltrans.com and then call the owner Bill K. about his Smart Box. He also sells a improved valve body and torque converter which will help your transmission work better.

 

[Pit Bull]

35K miles, have you flushed and refilled your cooling system? That roar you hear is the clutch engaging. Since you are at such a high altitude and pulling at or beyond the max, I would say that if everything is not working perfectly you would see some over heating. Let us know what ends up being your problem.

 

[groser]

Thanks for all the replies folks. I do shift out of OD well before the downshifting begins, at bottom of hill in fact. The cooling system was flushed and replaced at 21k by dealer. I found another thread that states some drivers are going up and down the Eisenhower (7% grade for over 15 miles) at +55 MPH with heavy loads. Total gross for my truck and trailer is around 21,300 lbs average and I'm only doing 30 MPH last 1/3 of the grade, in 2nd gear @ 2700 rpm. If I take it out of 2nd into 3rd it up shifts and then downshifts back into 2nd as long as I pedal down to keep 2700 RPm My first diesel; is this normal?



Next I'm going to try cleaning the radiator fins with air tool even though they look clean with mirror. Then investigate the fan clutch a little more plus check if Cummins has dyno rather than me running up and down the mountain with my fifth wheel which is what Dodge dealer wants me to do.

 

[Snow man]

groser. it sounds like your truck is normal,your just overloaded. The fan is coming on when it gets hot,what do you call overheating?what is the temp on the guage when its overheating? I think your truck is fine,if the temp comes down when the fan kicks on,its not overheating,if it ewas too hot the fan wouldnt kick back off,it would stay on constantly until the engine temp is down to a safe level.

 

[groser]

Snowman, I didn't make myself clear. Occasionally I hear the fan kick on at mid range on gage and then temp drops and fan noise stops. However it doesn't always kick in when I think it should and when going up long grades the engine is pulling so hard I can't hear the fan kick in or out.

When I say Overheating I mean going into the red zone on the gage. It takes a long grade to get it there, the temp just builds slowly. Once 2/3 of the way on the gage it then moves rather quickly toward red zone and I pull over. Don't have transmission temp gage but when I pull stick the fluid temp seems pretty normal to the touch. Doesn't burn me! Maybe I am overloaded but the 21,600 lbs was weight on a truck scale and I read about others making it over the mountains with same kind of loads at even higher outside air temps. Am I expecting to much?

 

[M Barnett]

Next I'm going to try cleaning the radiator fins with air tool even though they look clean with mirror.

Please do this for your own peice of mind. I recently found two trucks that were overheating and the radiators were clogged with bugs even though they looked clean. Be sure to use air and not water. You can buy a short piece of copper tubing at any hardware store, 5/16, and get a ferul and fitting to match your blowgun and you've got it. Also get a cheap small tubing bender so you can get a small bend in the end of it. Good luck

Michael

 

[Boldt's Wagon]

You are expecting too much for a stock rig. A 7% grade and 21,300 lbs at 55 mph requires about 310 rear wheel HP. 35 mph, 21,300 lb, and 7% requires 180 rear wheel HP. With your automatic in non lockup, you are probably putting 30-40 HP into heat loss in the torque converter. Most of the transmission heat is removed in the water cooled heat exchanger under the exhaust manifold and looks like it results in overheating with your rig.



You need more HP to maintain your speed in 3rd lockup or get a transmission system that allows TC lockup in 2nd with the stock HP. Your observed 30+ mph for the last third of the grade looks about right for your weight and stock engine/transmission.

 

[JTroiano]

You can use a garden hose to clean your radiator, intercooler and condenser. It works better than compressed air. I don't think it is normal to get that hot. I could maybe see it getting a little hot if it was 90+ degrees out and you had the AC on. I would look in the radiator and see if you can see the tubes. If you can you can tell if the are getting plugged, which I don't think they would be at 35k. Then I would put the 180 thermostat in and start looking at the fan clutch. I would also get some "Water Wetter" to add to the coolant. I think it is made by Red line. It does work! Then a must is to get a set of gauges, especially the trans. temp. gauge, it could be slipping and cooking the coolant and the trans. I have seen auto's crap out as little as 35k.

Jon T

 

[groser]

Boldt's wagon

You need more HP to maintain your speed in 3rd lockup or get a transmission system that allows TC lockup in 2nd with the stock HP. Your observed 30+ mph for the last third of the grade looks about right for your weight and stock engine/transmission. [/B][/QUOTE]



Don't understand the AT talk. Are you saying my TC does not lock up automatically in 3rd or 2nd? When in 3rd it downshifts automatically to 2nd because I'm asking for so much horsepower? How does one get the TC to lock up? After market product?

 

[jerrethomas]

a horton fan would take care of the overheating issue

 

[BLee]

Your truck will not lock the T/C in second gear, so you are building a lot of heat in the transmission when it downshifts to 2nd and you turn 2700 rpm. I think the experts will tell you that you are experiencing shear of the transmission fluid, producing heat. You can buy a Smartcontroller from DTT or ATS or maybe others which will allow you to lock your T/C in 2nd or even 1st gear. Cost of a Smartcontroller isn't bad. Problem is you are going to destroy the T/C clutch anyway by slipping it if you keep pushing it up those grades with that kind of weight. You need to look into transmission upgrades for heavy towing. Otherwise your transmission is probably going to have a short life. Call DTT or ATS or others soon.

Bill

 

[BLee]

Incidentally, my book says your Auto 4. 10 3500 is rated for a max GCWR of 18,000#; only the manual transmissions are rated for 20,000#. Therefore you are almost 20% over rated weight. How are you slowing that much weight down when you get to the top of the grade?

Bill

 

[98rammer]

just to add a side note, my truck (not sure about the 24valvers) will not lock in 3rd with my foot to the floor. about 7/8 and under it will lock in 3rd, but beyond that is only a couple more mph and more heat (obviously) with fluid coupling.

 

[Snow man]

Groser,your auto is releasing a lot of heat into the radiator,thru the engine block mounted cooler,this is a lot to ask fo your stock truck,in the mountians,the standard trucks are rated higher due to this heat load they do not have,along with trans strenth. From what you say,you do need to replace the fan clutch,since it isnt engaging,but i think some of this is rom related,you may need to buy a horton fan. I know my truck could pull that grade in 3rd lockup at 55 mph,which is 2400RPM,i dont know if i could keep EGT's at 1300 od under though,this would be the challenge to be able to pull that grade,and keep egts in check.

 

[stseeber]

Groser: You might want to get your lift pump checked out? Your problem on long grades are exactly what happened to me @ 58k in my 99-2500 towing 4k lb trailer. Truck would overheat and violently downshift. when I would pull over it would cool down almost right now. Never was their a boilover. Not enough fuel was getting to the inj pump and causing it(according to stealer in Quincy, Ca. ) On the level noticed slight fluctuation in tach. New lift pump solved the whole hillpulling overheating problem. Anyway it is just a thought and be advised to check out all the lift pump threads on TDR. Sincerely Steve in Calif.

 

[InThinAir]

First of all Welcome to Colorado!! I think that you see level boys are just attaching heavy stuff to the cummins and pulling up anything. In the thinner air and the steep grades it just doesn't seem to work that way. You have to moderate and watch your speed and your EGT and fuel pressure real close.



My ETH hits 900* EGT POST turbo just driving up to my house in the neighborhood. Thats completely unloaded. You put the Slide in camper and attach the horse trailer and I hit 1100 all the time. So my truck takes 4-5 minutes of idling in the driveway to reach temps < 400, before I turn it off. But I think I am in the extreme, when I pull into my driveway I am at 9800 ft above sea level.



Other than the paint on the hood starting to discolor from the heat of the engine, I think that I am OK. 60k miles and still going strong.



I think that you should perform regular maintainence and make sure that your lift pump is working and you have a good and I mean like brand new Air filter. And if you want to play "InThinAir" a big exhaust doesn't hurt either.



---Doug