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  • Fixing Dodge Durango Transmission Problems by Replacing Sensors

    Posted on October 10th, 2013 Lee Devlin 7 comments
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    I recently encountered a problem with my 1999 Dodge Durango’s transmission that was repaired by replacing some sensors. Whenever I discover the solution to a problem I’m having and figure that there are a number of others who may be having the same issue, I like to post the discovery on my blog.

    I purchased my Durango new and it has been the most reliable and useful vehicle I’ve ever owned. I love it. So when the transmission started acting funny after about 130,000 miles, I began to think my luck had finally run out. I was impressed lately when I took it to a Grease Monkey and learned that one of their other customers owns 2 Dodge Durangos of the same vintage as mine and each was approaching 300,000 miles with no major issues.

    The transmission problems were especially worrisome because I’ve recently acquired a light weight camper (a 16′ Scamp) and have begun taking it on camping trips. I expect to be using it a lot in the future and that will include towing it up some pretty steep grades in the Rocky Mountains here in Colorado. So I need a vehicle I can rely on to handle the task.

    Dodge Durango and Scamp 16

    The issue I was having was most noticeable when I was starting out from a dead stop. The vehicle seemed to surge back and forth shifting up and down, with the RPM climbing and falling. It would do this for as long as I held the accelerator in the same place. It was almost like a positive feedback loop. But if I stepped down harder on the gas, the problem seemed to go away, instead of getting worse, which wouldn’t generally happen if something inside the transmission was at fault. When your transmission is sick and you ask more from it, it usually demonstrates the problem with even more enthusiasm. But that wasn’t happening in my case. It seemed like it couldn’t decide whether it needed to upshift or downshift at a particular speed which was in the 10-15 mph range.

    I started searching for Dodge Durango transmission problems on Google and came across a YouTube video that showed a similar issue, except this guy was having his problem at 70 mph where the vehicle kept dropping into and out of overdrive. He said in his research he had read about transmission problems that could be related to both the throttle position sensor and the transmission speed sensor which are both relatively inexpensive and easy to change yourself. His video goes into detail on how to change the throttle position sensor and it looked quite easy.

    I also found a website that talked about how to test the TPS using a volt meter. However, I found that the voltages were impossible to measure because the plug that connected to the TPS is all sealed up. So I reasoned, based on the description of the test, that the throttle position sensor was a simple potentiometer and the way to find a problem with it was to rotate it while watching the resistance level. By removing the plug, I was able to get alligator clips on the potentiometer’s left and center conductors and I carefully rotated the potentiometer from idle to maximum throttle by rotating the linkage on the throttle body. Ideally, it should read from about 800 ohms to 5 K-ohms and increase consistently while rotated in one direction.

    Durango Throttle Position Sensor

    Image of a 1999 Durango Throttle Position Sensor

    The Sensor is easy to access on the side of the throttle body.

    The sensor is easy to access on the side of the throttle body just under the air box.

    Instead of smoothly increasing in resistance, I noticed a point around 1200 ohms where the resistance would increase, but then go DOWN about 200-300 ohms for a while, and then come back up even though I continued rotating in one direction. This defect would cause the voltage to do something similar, so I reasoned that the TPS was a likely candidate to be changed first.

    These sensors are easy to find in local auto stores like O’Reilly, Autozone, NAPA, etc.. where they keep them in stock. My web search on the Autozone site assured me that the TPS333 (the model my 1999 Durango 5.9L used) was in stock at my local Autozone store. I picked it up for $34 including tax. It came with extra mounting screws, an O-ring, and a gasket. Although my existing sensor had no gasket, I figured it wouldn’t hurt to install it. It was very simple to remove the old one and replace it with the new one using a Torx T-25 driver. The only ‘tricks’ were that I needed to press in on a latching mechanism to remove the plug and that you have to rotate the part slightly as you install it to get the shafts to mate.

    I rotated the linkage by hand to make sure it moved correctly and then I took it out for a test drive. At first, I thought that this had completely fixed the issue. However, it came back after a while so then I tried replacing the transmission speed sensor, a part that costs around $20 and requires a bit more effort to replace. It’s on the driver’s side of the transmission housing and I found it necessary to remove the plate that protects the transmission in order to get a wrench in closer to it. After I replaced that item, I noticed no difference.

    I continued to drive the vehicle for a few more weeks and noticed that a new problem had emerged. Sometimes while accelerating, the transmission wouldn’t want to shift into a higher gear. It was frustrating while attempting to achieve highway speeds only to see the tachometer approach the red line. Usually, I could get it to shift by dropping it into 2nd gear with the shift lever, then back into drive and it would usually shift properly after that. This was an intermittent problem too, one that I feared would be hard to diagnose and fix.

    The only other candidates that I could think of based on my research were the governor solenoid and governor pressure sensor. Unfortunately, these parts are inside the transmission and are a bit more expensive (about $80 for the sensor and $120 for the governor solenoid). Of course, that meant dropping the pan which is a messy job. I knew that the transmission was due for an oil change, and that I hadn’t ever had a proper oil change where they could access and change the filter (most shops today rely on a ‘transmission flush’, which means they suck out the old fluid and don’t actually change the filter). So I figured that I could combine a transmission fluid and filter change at the same time the governor solenoid and its sensor could be changed so I could more easily rationalize paying nearly $200 in labor to a shop instead of doing it myself.

    I took the vehicle to the local AAMCO shop and explained what was happening and they agreed to test drive it with a scanner so they could monitor transmission oil pressure. What they found was that the pressure never got above 30 psi and this was causing erratic shifting, indicating that there was something wrong with the governor solenoid or its pressure sensor. These parts are nearly always changed at the same time since if one is bad, the other is probably also worn and you need to drop the pan to get to either one so it just makes sense to do them both at the same time.

    I am happy to report that after spending another $450, the transmission is back to normal, shifting precisely when it should and hopefully ready for another 135,000 miles before needing any repairs. In the 15 years that I’ve owned this vehicle this is the only repair I’ve other than routine maintenance and since the vehicle was paid for long ago, I don’t feel too bad because people who replace vehicles every few years can end up spending that much monthly on a loan or lease payment.

    In reading through several forums, I read a horror story where a Dodge dealership wanted to replace the entire transmission for a similar problem for around $4000 but the person declined and found fixed it by replacing the throttle position sensor. So I think it makes sense to try with the easy/inexpensive fixes first and then work up to the more difficult and expensive parts. At the least, you’ll have the peace of mind that all your sensors are good as new.

    So if you have a Dodge Durango or Dodge truck based on the same chassis and you’re having transmission issues like I described, you may want to change these sensors to see if the fix works for you too. There’s too high a temptation for a dealership or transmission shop to want to ‘over repair’ and hence over charge for a simple issue like this.

     

    7 responses to “Fixing Dodge Durango Transmission Problems by Replacing Sensors”

    1. U may also like to try seafoam trans tune i was having similar problems and found this worked well

    2. I am so glad I found your article!!!
      I own a 2002 Dodge Durango SLT V8 which has also been a very reliable car for 9 years & is nearly paid off…
      I’ve been noticing several things starting to go wrong over this last year & have contemplated selling it before what I think might be a major transmission repair.
      My shifter began sticking in park or would not engage in park, the oil pressure suddenly drops no nearly zero sometimes for no apparent reason, the cooling fan sticks on, while accelerating the transmission sometimes doesn’t want to shift into a higher gear & I have had to do manually shift it down into 2nd & then back up, once it even accelerated much faster without me pressing any harder on the gas peddle & when I let off it decelerated immediately, nevertheless, it was kind of scary!
      It recently reached just over 100,000 miles & as I arrived home two days ago my shifter got stuck in park while stopped at my gate to open it. After some manipulation I finally got it into drive & parked it, but the dash light showed that it was in reverse. I shut my car off & tried to start it again thinking it may be a sensor or something & it would reset itself but that didn’t work and my car wouldn’t start. After some investigating, thinking it had to be the linkage, my boyfriend discovered that my shift cable had actually broken.
      While searching for a new shift cable online I came across your article & it gave me renewed hope & such a sigh of relief to know that maybe all the things that are happening can be fixed by replacing some simple sensors!
      I think I’ll start by checking the ones you mentioned….
      Thank You for taking the time to write this article!

    3. I have a 99 Dodge Durango the v8 Magnum I’mhaving a problem with its slipping a little bit In N Out at 80 kilometers if you know something about it can you get back to me thank you have a good day…

    4. Mr. Martell-
      There is a 4th (fourth) transmission sensor Mr. Devlin didn’t mention, (not that he needed to) and it has to do with the overdrive/lock-up. pt.#22954B (I think is what it’s called) I have a ’99 Durango with the 5.9L/518 Tranny and this may be your culprit. Sometimes these transmissions will inexplicably shift down from overdrive to a lower gear. These types of sensors rarely go bad, but they occasionally do according to my mechanic. Check it out. Price is around $130 or so, and the labor is a little bit more involved considering the fact that the valve body will have to be removed. I’d change the throttle position sensor FIRST before I did anything else. See if that fixes it. If not, get your transmission serviced and replace all four (4) sensors. There are also two bands that can be adjusted in the Dodge 518 transmission, but any reputable transmission repairman will know this.

    5. 99durango shifts into drive at like 55 was like 45 wanna fix before it messes up my tranny any help on what might cause this

    6. I have a1999 dodge Durango it won’t shift out of 1st gear it shifts into reverse fine but won’t shift out off 1st,some one told me it could be shift modual or pressure sensor is this true.

    7. I was having the same problem with my 99 Dodge Durango thinking it was the transmission I ended up having somebody clean out the throttle body and the car stop jumping around so that’s something that somebody could think about doing I also replace the speed sensor as well

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