I have a 2001 Dodge Durango 4.7 liter SLT, 140,000 miles.

Last week, I felt a kind of "stumble" as I was driving uphill. The stumble is more frequent now. The engine doesn't stumble when I run it in nuetral and the car doesn't stumble when I'm going downhill. The stumble feels a little bit like an automatic transmission shifting down as the car goes uphill...but not as smooth.

Does anyone recognize the symptom? If so, what should be done to clear the problem?

Thanks,

 

Is the check engine light on ? What happens if you shift manually ?
Sucks but it may be close to rebuild time

 

No engine light. Transmission fluid is good. Do you know of any symptom checker like for people at WebMD? If I do need a rebuild, that would be OK, but I would like to foreclose less expensive repairs (if possible) before I take it to a tranny shop.

 

I will do some manual shifting and let you know what happens.

Start (in P) RPM surges to 1600
In two minutes, RPM falls to 1000, then fluctuates briefly between 1200 and 1000, finally settles at 900
Engage R with brake on, RPM falls to 300, almost dies, recovers to 800
Engage N with brake on, RPM surges briefly to 1100, then falls back to 900
Engage R again, RPM falls to 300, almost dies, recovers to 750

Manual shifting from D to 2 and then to 1 while driving maybe 30 to 40 mph is smooth, no stumble.
Only stumble while driving uphill in D
No stumble while driving up hill in 2 or 1

 

Just because the light isn't on, doesn't mean there arn't any codes in the computer.

You could have pending codes either in the PCM or TCM. Could be something just as simple as a VSS.

BUT. Then again, if the light hasn't set and this has been going on for a while, most likely an internal issue. Or it could be somewhere else in the drive train.

Even as easy as wheel weight balance or ball joints. Dodge trucks and SUV's are notorious for ball joints...

 

Hi blue,

"Just because the light isn't on, doesn't mean there arn't any codes in the computer. You could have pending codes either in the PCM or TCM. Could be something just as simple as a VSS."

I don't remember exactly how to get the code or codes. Something to do with turning the key on and off several times, I think. Could you jog my memory?

If I got a code or codes, I guess that (might) point me in the right direction. I replaced the PCM several years ago.

"BUT. Then again, if the light hasn't set and this has been going on for a while, most likely an internal issue. Or it could be somewhere else in the drive train."

First stumble was a couple of weeks ago. Now, if I drive 20 miles, I might get a stumble or two.

 

Your typical autoZone scanner will probably NOT read transmission codes. But check it an ign problem could fool you and it may go int limp mode.. Best to start by removing the pan. Drain the fluid into some type of container so you can reuse it if needed.. Check to see what is in the pan. It could be the converter going bad they were good for stripping the splines.

 

That doesn't sound like a tranny issue as much as a fuel/idle issue (O2 senors, IAC, TPS, fuel system, etc.). If it was a tranny issue, the motor would not be acting like it is and you would have the symptoms whether in "D" or manual.

 

I'm hoping it's a fuel/idle issue. I didn't notice (or pay attention to) the RMP discrepancies until after I'd had the stumbling problem for a week or so.

I have not had the stumbling problem before, but I did have a problem that was fixed when I replaced the PCM several years ago. I can't remember the symptoms exactly except for fluctuating rpm which I now have...though much less than several years ago

This...

Manual shifting from D to 2 and then to 1 while driving maybe 30 to 40 mph is smooth, no stumble.
Only stumble while driving uphill in D
No stumble while driving up hill in 2 or 1

...makes me wonder if fuel regulation by the PCM or O2 senors, IAC, TPS, etc could be factored by engine load. The car isn't stumbling often, but it only seems to happen when the engine is loaded (by uphill driving) in D. (It might stumble in 1 or 2 as well, but I don't usually drive in 1 or 2 and I haven't seen that happen.)

What can I do to investigate possible fuel regulation etc. issues?

 

check out your egr, it was a problem with the 5.2/5.9 motors, im not sure on the 4.7 though.

 

RR, how do I locate the egr valve and how can I lubricate it in case it's sticking?

btw, I checked the trouble codes and found none. (a "p done")

 

autozone doesnt show you have one


anyways, i did some troubleshooting on there and here's what they said:

Feels Like
Symptom: Delayed Shifts
When: Driving
Where: Transmission


Priority|Action|Part Type|Cause|
1|InspectTransmission Modulator(Automatic) | MisAdjusted, Disconnected, Faulty Modulator Valve.
1|InspectTransmission(Capacity) | Incorrect Transmission Fluid Level.
2|InspectTransmission Shift Linkage (Auto) | Improperly Adjusted or Damaged Shift Linkage.
3|InspectAutomatic Transmission | Internal Transmission Damage.

 

Re "delayed shifting", the stumble happens most often when I am climbing hills, and that could be a delayed shift. Occasionally, I feel the car stumble briefly when I'm driving with a constant gas peddle (not accelerating or decelerating) on a level road. In those cases, I'm not sure the transmission is trying to shift or why it should try to shift. I get a dramatic rpm drop when I'm sitting in idle and manually shift to reverse, but I get no stumble when I'm driving and manually downshift from D to 2 and then to 1. I tried that a few times and got no stumble.

 

Sounds to me like its not the trans, its the torque converter.

 

Matt, What should I do from here? Take it to a shop for a check-up?

 

Your TC could be breaking up inside causing your issues. If it is, you may need to have the whole tranny rebuild (wouldn be a bad idea since the tranny will be pulled out at that time anyways).

What color is the fluid? DId you ever drop the pan by chance or just look at it on the dip stick?

 

Fluid is pink, pretty much the same color as ATF-4.

I am not familiar with the term "pan" in the context of the AT. I know that oil pans exist, but I have never dropped one. Is it hard to drop an AT pan? I gather dropping an AT pan might show metal particles (or might not - if the problem wasn't due to internal damage).

 

yeah i'd at least go talk to a trans shop. but im assuming this is the original trans so im surprised its lasted this long. a rebuild is prob what you wanna do, if the torque converter is whats wrong.

 

Thank you sir, I will take that advice.

 

No problem! Just helpin out a fellow mopar nut.

 

On the newer transmissions with overdrive if you rebuild one it is almost mandatory to replace the converter

 

This may be a long shot here but I had a problem a while back with my Mazda tribute. It started out every once in a while as a stumble in between shifting, and then it started feeling like the gears were slipping as I was going uphill. I took it to a service garage with the fear of needing a rebuilt transmission. The actual cause was I had three bad ignition coils. So check those out and that may be your problem. Hope this helps.

Jon P.

 

Take a volt meter and measure TPS sensor voltage at curb idle in park? If you are giving it gas and the transmission doesn't see the input then it will surge and slip. If it happens at load / up hill and it does it consistently at the same spot in the throttle look there. They go bad due to the constant use on the rotator in the sensor. They dont code out bad until they are junk and don't function. But the symptoms come first. Even then they only code high at .80 and low .59 (I think). They should be .78
At .72 you will see symptoms.

TV cable need to be spot on. 1/8 inch can cause slips, rpm limiter kicking it, slap in upshifts etc...