Problem with towing - Mit Challenger

[Bobkat]

This was originally posted on Caravanners Forum by another member (http://www.caravanersforum.com/viewt...hp?f=2&t=31068) but I had similar happen to me.

I was towing our van of approx 2500kg back from Albany a few weeks ago. As usual, I was using the auto in the manual/sports mode which tends to hold the change longer and prevents selecting 5th gear.

On one hill which I don't recall as being overly big, the box changed back into 2nd and when I tried to change up by pushing the stick forward, nothing happened. I finally pull the stick to the right into normal auto mode and then it shifted up fine.

The weather was very cold that day so I don't see this as overheating of the tranny.

Has anyone else had this happen?

[cry_babys]

i have had this happen twice each time towing but putting back in to drive did not fix but going to neutral and back to drive then every thing was fine not very good that it seems to be happening to others as well

[PeePee]

I have experienced this 3 times now, first time towing a van (1,500 kg) on a windy road, had to stop to get it out of second. The 2 other times have been on the beach when driving for longish periods in the soft sand. Stopping seemed to fix it but it happened again quickly. I am taking it in on Friday to be checked again. I am considering an oil cooler to fix it.

[Bobkat]

Hi PeePee.

Would be interested in any feedback you get from Mits people.

Your mention of a tranny cooler indicates you are thinking this is heat related so I assume that it was a warm day and/or the terrain was extreme.

Maybe when you drop it of you should ask if they have a larger tranny cooler as a stock part as this would indicate that they are aware of a overheating problem.

A few years ago I put my EL Falcon into Automasters to have a tranny cooler fitted thinking they would use an OEM unit but the only one they could find was the genuine Ford one specifically for that model.

Bob

[old Jack]

more info please

Hi Pb Auto Tow-er's,

I been trying to get an updated Genuine Manual for months as the Mits PN. AU900055 does not fully cover the 5 speed Auto in all sections of the Manual so I am working with 1/2 or at the best 2/3's of the information therefore I can only theorise/guess at how it all works.

I have a theory, that the programming of the Auto Computer (ECU) is best suited for the V6 petrol engine that is sold overseas and not the 2.5 turbo diesel which has very different torque and power curves. I suspect the same Auto ECU program is used for both engines. Can't confirm it yet it is just a suspicion!

I too have been having "strange happens" with my Auto when it is working hard and this has been checked by the Dealer, no faults indicated and all under warranty/no charge.

Question 1.
Are your Challengers fitted with bullbars and driving lights, if so what type?
There may be a common factor do do with airflow. I doubt it but it is the first thing the Dealer will suggest if it is not a Genuine Accessory!

There is a transmission cooler fitted as standard, but these along with the radiator and intercooler can become blocked if you have driven through dirty/muddy water and not cleaned throughly.

Question 2.
Did your "A/T Temp" warning come on? it is a red illuminated "A/T Temp" indicator that is on the lower right quadrant of the Tacho, when the ignition is switch to "on" it illuminates until the car is started.

Question 3.
Have you checked the transmission fluid level?
This must be done with the fluid warm and the engine RUNNING as per 8-10 of the Owners Manual! Check the level, colour and transparency of the fluid.

Question 4.
How many km on the Odometer and what year of manufacture?

Question 5.
What size tyres are you running?
tyre width?
tyre profile?
rim diameter?

From the research I have done, there are aftermarket valve change kits and torque convertor lockup over-rides available that improve the gear changes and lockup the torque convertor when towing which apparently help with the problems. I have not fitted any of these yet as I am concerned about warranty validity and I believe IF my V6 ECU theory is correct then Mitsubishi should fix the problem with a revised AT ECU program to suit the diesel!

cheers, old Jack.

[old Jack]

More info to confuse?

After some more searching through the manuals (very difficult and confusing to find info on this multi layered CD) I can now confirm that my theory is WRONG, there is a different ECU program for the 2.5 diesel 5 speed Auto.

AT ECU has 11 inputs (sensors & switches) and 10 outputs that control 7 actuators, solenoids or valves & 3 indicator outputs.
There are 25 fault codes that relate to mechanical / hydraulic functions and 6 fault codes that relate to the electrical /communication functions.

When a fault code is logged in the ECU then the "D" or "5","4","3" display FLASHES. This means a trip to the Dealer!

The AT Temp display comes on once the trans fluid is at 135C and will not go off until 115C. There must be a way of connecting an actual temp gauge to this or maybe a Scangauge II will give you this temp.

The Auto ECU has INVECS-II which is an adaptive learning program which changes the shift patterns to suit your driving style I am not sure how it functions but I am told it stores the last 200 drives and uses this info to modify the shift patterns of the Auto. This "memory" can only be deleted/reset by connection to MUT-II at the Dealer. Disconnecting the battery will not work as ECU has internal battery/EEPROM backup.

From reading the Manual there are multiple test procedures that can be carried out once connected to the MUT-II and the car is driven, this process is recommended if no fault codes are registered.

Worth knowing is that in "manual mode" when you shift up / shift down a gear this is viewed by the ECU as a "request" and not as an action therefore the ECU will only act on your "request" when all the preset conditions are met. Trouble is I don't know what these are, but guess it will be engine rpm, throttle position, input and output shaft speeds, car speed, brakes on/off, cruise control on/off, 4H/4HLc/4Llc selection and probably more that I haven't thought of.

My hope is that if Mitsubishi do not come out with a improved program for the AT ECU then someone like MRT Performance might!
Then again there is always the Wholesale Automatic's valve body and lockup override kits.

I would like to work out how to connect an indicator LED to the trans that tells me when the torque convertor lockup is on or off.

Mmm, more to contemplate ! cheers, old Jack.

[PeePee]

Bobkat and Oldjack, thanks for the thoughts, I will look into all that and respond after the Challenger is checked tomorrow. I am getting the fluids checked alright just to be sure.

Yes I have an ARB deluxe bar, IPF driving lights and stainless steel bash plate so there may be issues with cooling. I will have this checked also.

[RogerB]

Regarding Trans fluid temperature - I have that function coded on my ScanGaugeII and the highest I have seen it is 98 degrees C while towing my 17ft van up the SE Freeway, so I imagine it's quite possible for it to go higher than 135C under more extreme conditions. Whether this has any bearing on the situation I don't know - just more information.
Roger

[Denmi]

Hi Guys, first post here

I have also had the same problem with the gearbox locking in second gear on a steep incline, (only happened once). We tow a 2400 kg full caravan and have had no further problems. I am considering installing a DP Chip to help with extra torque for towing. Do other owners think this would help in regards to not having to use second gear going up a steep incline or would it put more pressure on the gearbox????

Denmi

[old Jack]

Hi Denmi,

Welcome to the forum.

I am not sure if "chipping" your Challenger will help with the auto 2nd gear issue, the AT ECU is designed to protect the auto trans from possible damage if it operates outside the nominated limits. If one of the sensor inputs is incorrect then what you are describing may occur or the driving conditions that you were under did correctly cause the AT ECU to protect the trans.

Did you get the gear indicator flashing on the dash or the AT Temp indicator come on?

As for "chipping" if I was going to do this then a MRT reprogram would be my choice over a piggy-back style chip, they are more expensive but I believe the results are better. PM "Ballfyboy" he has a MRT reprogram and does a lot of off road towing.

cheers, old Jack.

[Denmi]

Hi Old Jack,

No A/T Temp Indicator or any other flashing on the dash.

This happened approx 7 months ago and have been up and down a few hills since then and nothing like that has happened again, (very fortunate i think).

It is a challenge to be able to tow a heavy caravan and have the vehicle perform to the manufacturers stated capability.

I understand about the A/T protecting itself (a good thing IMHO).

Thanks for the advice about the chip, i will have a good think about it.

Cheers Denmi.

[PeePee]

Hi Pb Auto Tow-er's,

I been trying to get an updated Genuine Manual for months as the Mits PN. AU900055 does not fully cover the 5 speed Auto in all sections of the Manual so I am working with 1/2 or at the best 2/3's of the information therefore I can only theorise/guess at how it all works.

I have a theory, that the programming of the Auto Computer (ECU) is best suited for the V6 petrol engine that is sold overseas and not the 2.5 turbo diesel which has very different torque and power curves. I suspect the same Auto ECU program is used for both engines. Can't confirm it yet it is just a suspicion!

I too have been having "strange happens" with my Auto when it is working hard and this has been checked by the Dealer, no faults indicated and all under warranty/no charge.

Question 1.
Are your Challengers fitted with bullbars and driving lights, if so what type?
There may be a common factor do do with airflow. I doubt it but it is the first thing the Dealer will suggest if it is not a Genuine Accessory! Yes - ARB Deluxe bar and IPF drivings lights.

There is a transmission cooler fitted as standard, but these along with the radiator and intercooler can become blocked if you have driven through dirty/muddy water and not cleaned throughly. No dirt as clean as

Question 2.
Did your "A/T Temp" warning come on? it is a red illuminated "A/T Temp" indicator that is on the lower right quadrant of the Tacho, when the ignition is switch to "on" it illuminates until the car is started. Nope, no warning lights whatsoever. And no records of issues when Mitsubishi looked at it today.

Question 3.
Have you checked the transmission fluid level? Yes all good
This must be done with the fluid warm and the engine RUNNING as per 8-10 of the Owners Manual! Check the level, colour and transparency of the fluid.

Question 4.
How many km on the Odometer and what year of manufacture? 16000

Question 5.
What size tyres are you running? 265/70/17 Mickey Thompson ATZ's
tyre width?
tyre profile?
rim diameter? standard issue on the MY12 LS

From the research I have done, there are aftermarket valve change kits and torque convertor lockup over-rides available that improve the gear changes and lockup the torque convertor when towing which apparently help with the problems. I have not fitted any of these yet as I am concerned about warranty validity and I believe IF my V6 ECU theory is correct then Mitsubishi should fix the problem with a revised AT ECU program to suit the diesel!

cheers, old Jack.

In discussing with Mitsubishi today mine is the first complaint on this matter. I am aware of another on the Sunny Coast and others noted here. Clearly there is an issue but they dont know what is yet.

I will keep on it and let you know if I uncover anything.

Cheers and thanks for your interest.

[Ballfyboy]

As for "chipping" if I was going to do this then a MRT reprogram would be my choice over a piggy-back style chip, they are more expensive but I believe the results are better. PM "Ballfyboy" he has a MRT reprogram and does a lot of off road towing.

cheers, old Jack.

I have had this issue on a few occasions. Always seems to be when towing over very steep stuff for a little while. My temp is ok and no warning lights have come on, it just stays in 2nd. Sometimes it happens on the down bit as well as the up?? I have never had it happen on a flat or even on moderate slopes.

These days when it happens I just flick it into N whilst driving and back into where ever it was before it happens and it is usually right for a fair while, then I just repeat when needed No doubt some smarty will come up with the exact reason? The kids fighting in the back bother me far more than this

I don't know what causes it, however if I had to guess I think it must be the learning programme together with some load sensor thingy with another temp sensor thingy multiplied by the ambient temp less the relative humidity x pi... I often wonder if the car had a torque lock out on the 2 & 3 gear whether it would happen?????

Thanks Old Jack for the vote of confidence in my knowledge lol. I am pretty happy with how mine drives. I would love to swap cars for a small drive with a chipped car to see the difference before stating that it was the "best" option. Maybe one day when I get some fee time I will go out camping again with the forum guys, dam study. (Wayne I'm sorry but I will come out soon, honest)

[PeePee]

I was thinking it must be from the gear box getting too hot and was looking to install an oil cooler. Mitsubishi confirmed there is a decent size oil cooler standard, which I have located on the front passenger side.

I have had this issue occur in two situations one while towing a van on a slow hilly bendy road, I wasn't driving hard at all just driving to the conditions. Once I stopped it fixed itself and I moved on. The other times have been on Fraser Island in the soft sand and the car was working a little harder than normal. This was due to the tide and I had little choice but to be in the soft sand.

Now that we have established this is not an isolated issue we should collate how many have this issue and their details and I will discuss with the service manager here in Brissy for starters. He drives a Triton and has it kitted out so I know he will be keen to look into a solution. Or i could direct him to this forum. He was not there yesterday for me to talk to but I will next week.

What's your thoughts.

[Ballfyboy]

I wonder if any triton owner have this issue?? I will search newtriton when I get a chance (could be a little while tho).