When I'm cruising around 65-70 mph I'm reving at about 2200. If I tap the go pedal the tach jumps up to 2900-3000. I've noticed decreased fuel mileage also. Is my torque converter not locking up? Can I fix the torque converter lock-up problem w/ aftermarket tuners or is it something else that is wrong? Any help would be great.

 

Sounds like it's not locking, and or it's slipping. It's definitely a problem. Could be a simple electrical problem/sensor.

Nick

 

I wonder if the Smarty updates the programming for the tranny as well. This would be a good excuse to buy one (not that a failing tranny needs a Smarty).

 

Try cleaning the battery connections and see if that helps.

 

Thanks, I'll try that.

 

TC is not locking, rpms at 65 should only be 1800rpm. Either the TC is bad or lockup valve is not working.

 

I think I'm going to just take it in to a tranny shop and get it diagnosed. Sounds like there are too many variables that could cause this problem.

 

RPM's will depend on what gear you have. What did the rpm's "used" to be? You may be better off having it diagnosed, as mentioned, but a lot of the things you can do yourself and save a ton of money. Are there any codes? Turn the key from off to on ( not cranking) 3 times and write down the codes listed in the odometer screen.

 

That's true. I think last time I took a truck to the tranny shop I was out a couple hundred just for the diagnostic. I'll check for codes...

 

It just says: "donE"

I'm guessing that means there are no codes being thrown. Is there any other way that I could hook something up to the ecu to find out if there's something electronic causing it not to lock up? Also do the tranny and the engine share the same ecu or do they each have their own?

 

Trans uses the Dodge PCM for its controls, but still should have had a code if there was trouble. Where is East bay? What have the temps been lately, and what type of driving are you doing? On shorter trips in cold weather, the overdrive will not engage due to low trans fluid temps, which causes the fluid to be thicker and the pressures to be higher as a result. This could all be normal. Just need to get more info. Also.....what were the rpm's before, or just never noticed until checking the mileage or?......

 

Sorry, should have given at least a little info. I bought the truck a couple months ago from a steal-ership. It had 70,000 on it and was in great condition. (Took it to a mechanic who checked out the ecu and drivetrain at the time and no problems with anything). I drive it as a dd right now and have a pretty light foot. TC locked up just fine until recently. I am in the East Bay in Pleasant Hill, CA so it doesn't get that cold (like 28 deg.). RPM's used to be at about 1800-1900 at around 65 mph. I recently noticed that the tach was reving to 2200 when cruising at 65 and figured the TC was obviously not locking up. I just found evidence of a 5th wheel hitch mount under the bedliner and holes in the frame rails so that makes me think this thing used to tow heavy . Dealer said it didn't tow heavy and I was stupid enough to listen to him. Should have taken a closer look before I bought it. The VIN indicated I have 3.73's so I KNOW the RPM's shouldn't be above 2000 when traveling around 65. Oh ya, the tranny fluid is at full when warmed up and it is red and clear. I wonder if my tranny has worn clutches or something else that is severely worn but wouldn't that still throw a code?

 

How far do yo udirve daily? The cold fluid still applies, even at 28*. Yes, the rpm's should be lower with 3.73's. Mine are near 2000 at 70. Or were before the larger tires I should say! Now......as far as worn clutches and such, you would have some sort of other noticable condition. Also.....if the TC wasn't engaging when commanded, there would be a code for "no rpm drop with tc engaged". From what you are saying, it may be worth having someone with a scanner hook up to the truck and look at several things. TC command ( on or off ) , brake input ( on or off, when the brake is on the tcc won't engage ), also look at the Governor Pressure Transducer, and solenoid duty cycles. BUT!!! First things first. What is the condition and level of the transmission fluid? Clean and red, or borwn and burned?

 

Tranny fluid is clean, full, and red. I'm a firefighter so I only drive it to work every 4 days and that is about 5 miles away. I have driven it on 4+ hour trips in warmer weather and it will still do the same thing. If someone with a Smarty or Edge tuner hooked up to the ecu would it tell me something about what the tranny is doing or do I just need a mechanic with other diagnostic stuff?

 

I believe that the Smarty and other programmers will only give you codes. You'll need to see live data from the ecm and pcm. I'd call a couple of tranny shops , explain your trouble, and ask for an estimate for a preliminary diagnostic charge. The 48 is a pretty reliable tranny. I haven't heard of too many going south , that have been maintained right. Mine has 165K on it! I don't to a whole lot, but enough.