I have a 2001 Durango with 215,000 miles. Never any issues or problems, other than the cooling fan resistor and drum brakes – UGH… Completely stock 4.7L with auto trans. Towing package with all the extras from the dealer. RUNS GREAT, until recently.

Overheating: Noticed the radiator was leaking (drip running down the side) and started to overheat slightly (always ran to the left of top center on the gauge, rather cool). I replaced the thermostat and radiator and seemed to run fine. Then I noticed the gauge climbing in traffic. Ding, ding, it overheated again. After cooling down I noticed the radiator overflow was completely full and spitting out of the tank. Refilled the engine and drained the tank, burped is as recommended and everything was fine again for a few weeks. Now it has done it again. I believe I have narrowed the overheating down to the fan clutch – never seems to be on high speed, just stays at a constant air flow. I was going replace the clutch and install a new radiator cap. Question, if it is the fan clutch, would a simple overheating cause the overflow tank to get filled up beyond capacity? And, what is the correct pressure rating of the cap? Manual says 18-22 psi, dealer cap is 21 psi, but cap from Advance Auto is 16 psi?

Second problem: While on the highway and trying to explain to my son the passing gear at 60 miles per hour, it went into limp mode. Never before had any issues with the trans, even went into the passing gear for a few seconds and then straight to neutral. Not a huge issue as I got off the highway, placed it in 1st gear and drove it home. Had the engine light go on with code 0121 (? – TPS) as typically noted in the forum. Did some research and called a few trans shops (who all wanted to rebuild as 215,000 miles is way too many miles on an original transmission). Long story short, I cleaned the battery cables, all grounding straps I could fine, and left the negative battery cable off for 10 minutes. This seemed to reset the TCM (engine light no longer on). After some investigating, I narrowed it down to possible over filling the transmission with fluid. Drained it to slightly below full and took it out for approximately 50 miles of driving at all speeds and it runs as good as ever – NO shifting problems. Took it by Advance to read the codes – NO CODES! Question, does this sound normal, or am I just having a false sense of security? Should I have it looked at by the trans shop, or just keep driving it until the issue arises again? I just don’t want to get stuck again and cause more damage (if any) to the trans.

 

For every pound of pressure you add you increase the boiling point of your coolant by 2 degrees...roughly. Stay with a cap inside the recommended range.Figure out how old your coolant is also.4.7's are particular about changing every few years to keep clean coolant in them.Head gaskets and timing chain covers are affected by old coolant and can leak,causing pressure build up in the cooling system.NOT tryin to freak you out,stick with your plan,freshen up the coolant if needed,check your belt and clutch,and yes,overheating can fill the overflow.
#2)When was your last trans service? If it's due get it done...NO FLUSHING,don't forget the cooler and lines,with the tow package you most likely have them...For the most part you can have it looked at but you're gonna get the hard sell an how BAD you need (an unneeded) trans rebuild,take your chances until an issue shows,if one does....Juz my 2c
Good luck man...

 

21 psi on an 2001 Durango, 16 psi was on the 1998-1999.

Not sure on capacity and how it could go over unless your heater core was air locked. Ensure the heater is on hot and HI both front and rear when burping the system.

P0121 TPS Voltage Does Not Agree with MAP

I would replace the TPS first. I remember reading somewhere that when it goes out it can put the trans into limp mode, could have been on the same circuit or something?

 

Welcome to DF
The overheating could many things. Does the durango have an electric fan and if it does. Has it come on during the overheating problem? Could also be a water pump, fan clutch or blockage somewhere in the block. Try removing the t-stat and see what happens.

Transmission problem could be the TPS or bad ground connection on the block. They are two ground wires, one on each side of the block.

 

Thanks for all the input.

Don't bash me when I say I have only changed the trans fluid once at 80,000 miles. I only change my oil at 8-10,000 miles and never used synthetic.

Grew up with a mechanic that had a different view of maintenance and I have to say my vehicles runs better and last longer than those around me that change everything by the book. Someday that may come back an bite me in the #@@... I chaecked the trans fluid last night and no signs of debris.

I think I’m going to take it in and have them change the trans fluid (messy jop for the garage) and filter(s). I heard from the dealer that there are two filters when I had an idol issue (still have it, can’t seem to fix). They said that the one they did not change is causing the idol issue I started to have. Could not explain why they did not shange it and refused to do it (I hate dealers). When warm and air conditioning is off, it idols down to 500 RPM when I come to a stop. Tap the accelerator and goes up to 750 RPM and stays there. Just an annoying bugger. Started after a flash from the dealer after trans fluid change and they said it is something they can not fix.

Also, is it possible that the TPS and MAP sensor warning could have been from a spike in RPM? I replaced the TPS with a dealer unit last summer. Truck runs like a top, no hesitation or anything else that would make me think the TPS is not working properly.
Narrowed the overheating down to the fan clutch, as I performed the plastic cover trick over the radiator and the fan never changed speeds. Ran the system open for a while and seemed like the water pump is working fine via verification of flow through the hose. Also, overheating seems to be an issue in traffic and at slow speeds, never at highway speeds. If it were the t’stat or pump, wouldn’t it overheat regardless? Electric fan works fine.

 

sounds to me like a bad fan clutch since it only overheats in traffic or at very low speeds, start with a new clutch and see if that takes care of it.

 

Well at least you changed the trans fluid....LOL....The manual states 60 intervals, we push 30k intervals here, but each to their own. If you have 2 filters in your trucks trasmission then you must have a 4.7L with a 45RFE trans. Can you give us more information like year and 4X4?

Oil at 8k-10k conventional is not a good idea in any form. The idea the oil base isn't bad is right, however the additives in the oil base are worn out and not protecting your engine. Lubrication is good enough, but isn't helping your cause any. Now if you want to do those intervals let me direct you to Mobil One Fully Synthetic avalible at Walmart in a big 5 qt container for only around $25 bucks. At least this way your additives will stay protecting your engine, it might not be the best but it's hands down better then the conventials you have been using.

Idle issue<--- Remove the throttle body and fully clean that thing out including the IAC port with throttle body cleaner (should take 2 cans). But it back on and reset the PCM correctly.

 

That’s correct, 2001 with 4.7L, 45RFE trans, and 4x4 which included all the high capacity towing package options (alt, cooling, etc.).
Tried synthetic twice, both times resulted in oil leaks near the rear of the engine. Conventional does not leak a drop – told it had to with conditioning the seals.

Totally cleaned the throttle body and IAC port when I replaced the TPS – did not help. Used three cans and q-tips…ugh

Radiator cap in vehicle manual states 16psi, factory unit is 21 psi, service manual states 18-22 psi - which is correct or does it not matter? (dealer/factory replacement is 21psi)

 

actually hydra, minor correction, any transmission with factory fill of ATF +4 has a 100k mile change interval, and the new truck (my dads 09 dak for example) have 120k mile change intervals recommended.


also the sythetic oil leaks a little bit because it is cleaning out the engine of any deposits left there by your very worn out conventional oil, that and the better base in the synthetic has smaller molecules which will leak through a much smaller hole than the conventional will, so when you see it leaking a little that is the deposits inside the engine being cleaned out (these are helping to seal it up with conventional oil)

 

mastertech
These are the straps correct? I have the same,block to bulkhead to fender.Only on the pass side the longer of them is disconn'ed,maybe goes to the hood?
jarnold12

Quote:

Could not explain why they did not shange it and refused to do it (I hate dealers).

The PO of my D had the dealer service the trans and they did the same thing,seems a popular way to cut corners for them....21 psi cap