I don't know if that's showing your age or not. I have always driven standard transmissions, except for my first car which was a 2001 Explorer SportTrac (now I'm showing my age). I know in the family's F250 Powerstroke, my explorer, and in the Outlander, overdrive is accomplished using clutches inside the torque converter to lock the transmission input shaft 1:1 with the crankshaft. Doing this not only removes any slip/loss-in-efficiency from using the fluid coupling (the torque converter without overdrive), but also keeps the engine 1:1 with the transmission input shaft when you are decelerating, which saves fuel because the engine doesn't have to burn gas to keep itself running. Also, in the Outlander decelerating in overdrive makes a very nice low note from the exhaust.

I read in the Mitsubishi service manual for this transmission that the appropriate steps to diagnose and fix this problem (torque converter not locked up) is...

1) Check and adjust the transmission range switch.
2) Replace the TCM.
3) Check the installation and position of the transaxle assembly and the engine.
4) Check fluid for burning, fouling, or foreign matter.
---Is the result normal?
----Yes: Replace the torque converter.
----No: Replace the transaxle assembly...

The fluid smells slightly burnt, but is also near the end of its service interval (less than 1000 miles, as we are less than 1000 miles from being out of warranty). I could see them going either way with that.

Seeing how this problem is intermittent and could fool the tech into thinking it's working, I imagine I will have to drive over to the dealer (120 miles away) at least once to check and make sure the problem is fixed before taking the car back.

 

The torque converter lockup clutch has nothing to with overdrive, that is all inside the transmission. 1:1 is fourth gear in the Outlander's Jatco transmission and 5 and 6 are both overdrive by increasing amounts. You'll notice in the following video there is no torque converter attached, but he shows the 6 speeds inside the transmission(toyota's 6 speed):

http://www.youtube.com/watch?v=fAZeCSZIU2g

What it does is allow the fluid pumping losses inside the torque converter to be removed by locking the input shaft to the output shaft, strictly within the torque converter, thereby removing the heat losses of the input vanes pushing the output vanes. This is accomplished with a friction band inside the torque converter(clutch) that engages in the higher gear ranges (4,5,6?) for fuel economy and heat management.

This is your Jatco transmission:

http://www.jatco.co.jp/ENGLISH/PRODUCTS/AT/JF613E.html

 

Well, I looked up the definition of overdrive, and you are technically correct. 4th is in fact 1.161 according to my papers, and technically there is no overdrive referenced in the service manual, which I now feel is smart move on mitsublishi's part because the definition of overdrive (in reference to this transmission) is stupid. Though technically the behavior my fords display which is defined as overdrive is displayed in this transmission as the torque convertor lock up. Ford's definition was whack, which is why I was using lockup interchangeably with overdrive. My assumption was incorrect.

Sort of what I said, wasn't it? Now that I understand the definition of overdrive, I will hopefully avoid upsetting folks who deal with automatics on a regular basis. Like I said I am but a lowly standard transmission guy, only able to change clutches, throwout bearings, and fluid, and I prefer it that way.

A little education goes a long ways.

 

A decent standard with a hardy clutch is worth its weight in gold these days. At least in north america. Unfortunately, we couldn't get a standard on either of the last two vehicles we bought.

With the advent of higher gear count automatic and lockup converters, ATs are getting similar mileage to a standards and taking the control out of the driver's hands.

 

I love my 5-speed in my VW, it's smooth as butter. However my clutch slips occasionally, but that's only because I have the car tuned. That transmission has taken some abuse and never given me a problem.

Well, a local dealer has the Outlander, they will try to recreate the problem, but have already pointed out to me that warranty could be denied because the adviser thinks (assumes) the rival dealer/previous owner never serviced it and since I couldn't provide records...

I didn't tell him the transmission was overfilled by a liter, a pretty clear sign someone has monkeyed with it. Figure if they are looking for an excuse to deny warranty that would be it even though the transmission was in fact "serviced".

I can tell this is going to be painful, for both myself and the dealer staff. I hate having to fight to get warranty. Is this normal?

 

So here is the final update with the dealer, 2 and a half weeks later...

After leaving it with them for 2 days, they decided nothing was wrong with it. After taking the shop foreman for a ride and replicating the problem, I learned that the adviser didn't exactly explain the problem as I had explained it, or at least not in a way that the foreman could replicate the problem himself. I provided a two page write up on the problem for the foreman to reference, and we left it with him confident that he understood what the problem and proper actions to diagnose it (even if he didn't tell me the actions he was going to take to diagnose it, I gave him a copy of the service manual pages on the topic).

As of today, I called the service adviser to learn that after the foreman ran all his tests and found nothing out of place, they decided to (appropriately, according to the book and the pages that I gave him) drive another vehicle of the same make and model and compare the behavior. The conclusion: the behavior is normal and there is nothing wrong with the transmission.

Fortunately (for them and me) I have had the experience just late last year into this year, that I had a car with a problem which everyone (including expert mechanics I very much respect) told me was "normal, they all do that, there's nothing wrong." In this situation after owning and working on the car for a year, I found the cause and not only a quick band-aid fix that buys 30k miles, but the real deal fix that will buy 100k.

The point is I think the dealership, did their job accordingly (after I explained their job to them), and while in this case they claim there is "nothing wrong with your transmission" because they have another which does the same thing, I respectfully disagree. The dealership just does not have the resources to find the problem.

So this leaves it up to me. I wonder, are there any Mitsubishi diagnostic tools available to us shade-tree mechanics? I know with VW I can get a VCDS cable to scan codes, read sensors and reprogram some features in the controllers. I don't suppose there is anything like that for Mitsubishi outside of the dealer, is there?

 

I've the exact same problem on a Montero limited. Were you able to resolve the prob?

 

TCU's sometimes needs to be reset as they can become confused by their built in logic, especially the "learning" TCU's.
I dont know if Mitsu has a set way to reset the TCU but disconnecting the battery for a few minutes should clear its memory.
I had a Kia Sorento with a Jatco tranny that had to be reset quite regularly. The way to clear that one was to pull the fuse to the TCU.
On the other side, it could also be any of the sensors on the tranny that is acting up.
Did you have it scanned for error codes?

 

My OBD is reading p0741 which is for torque converter lock up. I've scanned it on a professional scanner as well & torque converter does lock. The overdrive is making it slip. I've changed/checked fluids, sensors, solenoid, wiring is ok.

I'm not sure if Mitsubishi TCM has this resetting option but I've recently changed my battery & that I guess resets pretty much everything.

I've seen a lot of posts with this problem but nobody has an update except for one who ended up buying a used transmission.

btw thank you for your prompt response.