03 Durango 4.7 issues 265k miles
 

I had a issue awhile back when pulling a trailer with over drive off @ around 60-70mph, if I needed to pass a car so I could get into another lane I would press the accelerator petal a bit hard than I normally would because I was towing a 5k pound load, when accelerating almost immediately the engine would rev up to 5000-6000rpm from 2500rpm (at this point the check engine light came on, code p0340 read the code by using the onboard diagnostics and cleared the code at a local auto shop) and then It wasn't going to anywhere just dropping speed so I let off and pushed the petal lighter and it would pick up speed again. One time I hit it pretty hard to get around a dumb truck that was cutting me off and it revved up to 5k-6k again and decided to give it more throttle (check engine came on again p0340) and I felt a huge clunk and heard it then I started dropping speed and couldn't accelerate, slowed the car down and pulling over to the shoulder I noticed that my rpms were dropping as the speed was and after I got to 10mph the engine stalled out(right before it stalled the exaust made a loud pop noise), and shutting the car off then back on after 5min would fix the issue so I could accelerate again and this happened once more) keep in mind I had issues with the code p0340 and replaced the sensor with one from my local dealer 2 months before the trip. And the code would pop on here and there and would go away on its own knowing it was more than likely a bad wire so I ignored it as it really didn't bother me. After unhooking the trailer, I went on the high way and floored trying to replicate the issue and could not get it to do it with and without overdrive. Even though this happened about a month ago, I still like to know what caused that and wondering if the problem could happen at a later date without a trailer.

That's kinda strange, the code is for the cam position sensor, but, that shouldn't affect the trans like that. I suspect more than one problem there. The trans is slipping under heavy load, (trying to accelerate quickly while towing......) Will likely only be a problem while towing for a while, and progressively get worse. How quickly it happens depends on how often you tow.

That was the most I towed with it since it hit 120k I normally pull a trailer and load that weighs just over 2k lbs about once a week. But the drive pulling the heavier load was over 14 hours each way. We did have some hilly spots in Kansas/Missouri area it happened the most there.

I was also thinking it could be the torque converter going as the car has 270k on it now. Does a failing torqe converter seem right to assume?

I don't think so. Torque converter clutch will only change engine rpm by 200 or so, under normal circumstances. You are getting a much larger variance than that, which more or less points at clutches in the trans itself. With 270K on it, that really shouldn't come as a surprise. :D

Just wondering how the transmission has been maintained. Has it had periodic ATF and filter changes over it's life? If so, how often and when was the last time? How is the fluid level, smell and appearance?

The last time it was done was 170k same with the filter, the atf4 fluid is red but getting a bit dark now, the fluid level is still full from 170k, Haven't smelled it yet as I haven't had a need to. The trans has penzzoil platinum atf-4 fully synthetic in it. The thing is it hasn't done it since we towed last but I'm just concerned if it will eventually happen with out pulling a trailer. Every sensor on the transmission is original from the factory. When the issue happened the trans temp was about 185ish never topped 210 when towing on an incline.

You've got roughly 100K on that fluid now and have been towing to boot. It could be worn out fluid that's causing it to slip. I'd change it along with the filters. You've got nothing to lose.

I run Walmart Supertech ATF+4. It's the cheapest you can get and still good synthetic stuff. To live up to the ATF+4 rating, it has to be. I put in an aftermarket drain plug years ago and drain and fill every 25K, or whenever I happen to tow heavy any serious distance.

https://cimg8.ibsrv.net/gimg/dodgefo...08f4967440.jpg

Honestly, you're asking for something to break in the engine or trans by doing that.

By hitting the gas hard while pulling that heavy of a load at that high of a speed, you're dropping down a couple gears causing the engine to hit the rev limit instantly. The computer is shutting things down to protect the engine and trans from damage. The rev limit is about 6,000 RPMs on this vehicle/engine. In fact, you are probably significantly exceeding the rev limit the instant it hits the lower gear which is probably the cause of the P0340 code. Search google for P0340 rev limit and you'll find dozens of posts from people having the same thing happen.

I have a 2002 RAM 1500 with the 4.7L engine. A few times I've accelerated with the pedal to the floor and have never hit the rev limit. It's pretty much impossible under normal circumstances without being in neutral. Maybe on a steep, long hill you could do it without a load such as a trailer but not on relatively flat roads.

While doing some 0-60 runs, I found that my 2011 Challenger with 5.7L and 6 speed manual trans can only do 59 MPH before hitting the rev limit. Usually the car just loses power because spark and fuel are cut off and turned back on after reaching a low RPM. A couple times, I forgot to shift out of second while accelerating quickly and hit the limit. The CEL came on, lost all power and it started binging the chime like crazy. I had to turn off the car then start it back up to clear the issue. I didn't get a chance to read the code but I wouldn't be surprised it if was a P0340.