I have a 1999 5.2 2wd durango with 118,600 miles. Recently the check engine light came on and has stayed on. Now I don't notice any change in driving. Shop which gave the code said it could be:
1) torque converter 2) front transmission oil pump 3) torque converter clutch solenoid or transmissionA quick google search said this could just be a bad speed sensor. Any ideas?
Assuming that's the correct code that they retrieved and gave you, your shop is looking to gouge you for cash... P0720 is a speed sensor-related code... meaning probably a bad output speed sensor on the transmission, something that costs under $50 and takes about 5 minutes to replace.
Time to find another shop
P0720 = Output Speed Sensor Circuit
The light stayed on because once the code is detected it will remain "latched" unless the problem does not reoccur again within the next 50 starts, in which case it will clear on its own. (the code will remain stored but your CE light will go out). When they read the code for you did they offer to clear it for you? If they had cleared it (which they could have done quite easily) then you would know if it comes back again that there's something needing to be looked at. At 118k miles likely something is needing to be looked at, but the OBD-II scan tool cannot tell you exactly what the problem (cause) is, it can only tell you that (in this case at least) something caused the Output Speed Sensor to detect a fault.
Yes, it could be a bad speed sensor.
Torque converter has no sensors, and cannot throw a code.
Pump has no sensors, and cannot throw a code.
TCC solenoid can cause a code, but a corresponding change in drivability should occur.
I'd go with that. Tom Lawrence seems to be on top of the codes and could tell you for sure.
Well the thing is this shop has been very good to me. I've never been screwed over by them and in fact they never try and do more work than necessary. They even said they'd only charge me 30 minutes of work ($42) since they really didn't know what was wrong. I really do like the people here. Perhaps I can call back and just ask them to replace the speed sensor.
No they didn't however offer to clear this code, I guess that's a bit surprising. Strange thing is a few months ago it was having a different check engine light problem. It would flash, ding, the oil pressure would drop to 0 and then instantly back up. They replaced the oil pressure switch because that was their "best guess". It seemed to work temporarily but then came back a few weeks ago 2 times.
The exact information they gave me was "CODE PO720 - TORQUE CONVERTER CLUTCH, NO RPM DROP AT LOCK UP"
I was surprised to see all the quick responses :-)
Assuming that's the correct code that they retrieved and gave you, your shop is looking to gouge you for cash... P0720 is a speed sensor-related code... meaning probably a bad output speed sensor on the transmission, something that costs under $50 and takes about 5 minutes to replace.
Time to find another shop
Okay - then they're not being dishonest, they just looked something up wrong. P0720 is an OBD-II standard code, meaning it means the same on all OBD-II vehicles (as opposed to a manufacturer-specific code, which could mean different things on different vehicles), and that code refers to a problem with an output speed sensor.
So why didn't these guys know the same information that I've gotten here? Should I just go back with the information you guys have given and say that I believe it's the output speed sensor?
Again ... thanks for the response. I was thinking I was going to have to spend big money on my Durango. I love this truck and want to squeeze at least 200K out of it :-)
Torque converter lockup is pretty easy to test. Drive on the highway at a steady speed. Tap the brake pedal very lightly just for a second. This will cause the TC to unlock causing the RPM's to go up about 200 then immediatly drop back down if things are working normally.
You should go back and ask them to re-check, because everything you've read indicates that code is an output speed sensor malfunction, which has nothing to do with the torque converter or pump.
Nope - this one's most likely an easy fix.
I have a friend who rebuilds cars and has said that most of these sensors are easy to replace. The hardest part is knowing which one is bad and where it is. Is this easy enough for me to replace? Is the dealer the only place to get this sensor?
Since my 99 durango is getting older I'm sure I'll have more questions like this. Is there a site where you guys normally hang out or is this newsgroup the best place for these type of questions?
Again thanks so much!
The sensor is very easy to replace... it's on the driver's side of the transmission, towards the back of the case. It's got an electrical wire loom going to it, with a two-pin connector at the end. Once you unplug the connector, the sensor unscrews, then you screw the new one in. Very easy.
As for obtaining the sensor, there are aftermarket parts available. SMP (Standard Motor Products) makes one, part# SC104, and will cost you a whole $14.43 from
This group works, but you may find more people with Durango-specific knowledge over at
I replaced the sensor last night. I got it from a local auto parts store for $27. It was VERY easy to replace, I was amazed. Saved me some "transmission work". Truck is running great and shifting smoother now. Thanks so much for your replies!
Tom Lawrence wrote:
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