I bought a used '99 Durango SLT V8 with roughly 174,000 miles on June 30th, 2013. I test drove it hard. Price was pretty good and I didn't want a vehicle payment. I noticed while test driving it that the speedometer didn't always work, sometimes it would "bounce" and other times it would just flatline on 0 but it seemed to perform fine... Who really NEEDS cruise control anyway... I didn't consider it to be a deal breaker at the time.

A couple months later, I was driving home at about 40 mph. It suddenly down-shifted, wouldn't shift back up (no matter how much pumping of the accelerator) and limped it home at about 20-25 miles per hour. The next day I jumped in it and it drove fine, I could get it up to 70 mph on the interstate, etc. Over the course of a few weeks (Regretfully I didn't have the cash to get it into the shop immediately), it began to have this problem more and more often. I drove it only 5 miles or so to work and back each day and kept to 40mph or less streets. The check engine light came on and went off 2-3 times, I noticed the oil pressure went very high as soon as I pressed the accelerator and it started getting hot also in those weeks. Sometimes I could turn the truck off at a light and suddenly it'd drive right again but usually not. I turned off the AC. I put it in 4WD and took it back out. Nothing seemed to consistently help. I finally took the truck in to a very reputable local transmission repair shop.

First trip in - The shop changed the speedo sensor as was apparently recommended by the code reader. (I've since learned there's 2, one in front, one in back), I paid roughly $60 parts and labor and was delighted to get my truck out of a tranny shop for that price! (They DID recommend replacing the pan and a gasket between the tranny and the transfer case, OF COURSE, but I declined) It drove me home fine, drove me to work for a night shift but then on the way home the same day I picked it up, it did the exact same thing! (Including the speedometer bouncing, if working at all)

Second trip in, after the next payday - The code reader apparently had an error code for the governor solenoid, which made sense to me. I had to put a new pan on it after all or they wouldn't do the work, so roughly $440 later, I'm driving my Durango home again, new governor solenoid, new filter, new fluid, new pan. Within the first block or two it acted like it wanted to act up again, then drove the other 5 miles or so home fine (even on the interstate) with a couple of stops in between. The next morning though, it did the exact same thing!

Third trip in - It started off by driving fine to the shop after not shifting the night before. I picked up a guy who seems to be the lead mechanic at the shop. I drove him around a bit, drove it on the interstate, drove it harder than I EVER would had I not been trying to get it to duplicate the problem and dropped him off after it wouldn't do it (with him thinking I'm crazy). Not 6 blocks away from the shop, WHAM, it slams back into 2nd gear, speedometer flatlines again, won't shift up. I limp it back to the shop, walk in and the mechanic says, "You've got to be kidding". They actually pull another vehicle out of one of their 8 to 12 bays immediately, lift mine up and proceed to change both front and back speedo sensors again and the wires that connect the front one to the computer, all to no avail. I leave it with them for a few days hoping they can ponder something out. They've test driven it a lot, replaced the speedo sensors yet again, and it still seems to not want to shift sometimes, especially in the AM. Then I get the call saying they've done all they can think to do, the third gear lip seal is bad but that's nothing to worry about really, it should be good now and basically, "good luck" and "no charge" (Thank God). I drive it home and... here I am...

Please tell me someone KNOWS what's wrong with my truck! If not knows, someone who can start with the cheapest option it MIGHT be and list up. I'm sitting here at almost 2 AM typing this up after hours of looking on the net reading similar forums and with really no more money to put into this vehicle unless I know for sure it's going to fix it. Another dime into it means a dime less for the grocery budget. Another $500-$800 means the mortgage is going to be a month late.

 

I had the same speedo issue you described but not the shifting issue and it turned out to be the 4 wheel abs module. Turns out the speedo data goes thru the abs module. Don't suspect it is the same problem you have but then you may have more than one thing going on at the same time. Used module on ebay cost me about $80. I have been told they need to be programed for the vehicle, I searched and found one with exactly the same numbers and everything worked fine after that.

 

Did they try adjusting the TV cable? or atleast make sure its not binding... That could be your shifting issues.