Auto Gearbox Stuck in Limp Mode?

[AlfA01]

Hello.

I can't tell if my gearbox is in "limp" mode or if I have another problem. My car is a LWB 2006 Pajero Gen 3 5-door 3.2L DiD and auto gearbox.

For those that want to skip the history, the asterisks mark where I am today in my diagnostic process.

The problem I had from the beginning: I bought the car with a known issue--it wouldn't auto shift from 1st to 2nd. After manually shifting to 2nd, the car would auto shift normally until it returned to 1st. Then you would need to repeat the manual shift into 2nd. Reverse worked normally.

I drove the car and it started having problems on the road. It suddenly jolted into 3rd and would not shift manually or in automatic. The Trans Temp light was illuminated and N light was flashing. Also, the car would not move in Reverse.

I had the car towed home. I pumped out the trans fluid and dropped the pan. I removed the valve chest and cleaned and tested every valve's resistance in the valve chest. Most were 3.5 to 3.7 Ohms. I noticed a lot of metal filings in the pan and on the magnets. I cleaned it thoroughly and reassembled, filtered the fluid and reinstalled everything. The car would move in Drive, but not Reverse. No N light flashing anymore.

I decided to investigate further into the metal filings and ran the car again for the 10-20 minutes to warm the fluid after having reassembled everything. I once again drained the system and dropped the pan. The pan was full of metal particles again and a lot of brass filings were deposited on top of the valve chest. The transmission showed signs of a lot of wear, but I wasn't fully convinced that the gearbox was bad.

I found a gearbox locally at a great price and it didn't have the kilometers that mine did, so I bought it and swapped it in just the have piece of mind that the torque converter, bands or pump wouldn't just go out on me whilst in the middle of along journey.

***Where I'm at today. My worst fear was realized when the same problems persisted after replacing the gearbox and transfer case. Totally different auto gearbox and transfer case. New SPIII fluid and new filter installed along with brand new from Japan solenoid valves installed in the valve chest. I ran the car at idle for 20 minutes and checked the fluid. I do not have any movement in forward or reverse. It's as if the car is in Park or Neutral--the engine just revs and nothing happens.

Again, I have No flashing Neutral light. I grounded Pin 1 of the MUI/OBD terminal and only got codes from the transfer case, no transmission/gearbox codes were indicated.

I have asked someone to come over and read the codes, as the car is parked in a tight area that is fenced and I can't move it without reverse working.

Any help you guys can give is really appreciated. I'm sort of limited on my time that I can spend on the car right now, and the rain hasn't stopped for days...

Looking forward to sorting this problem out and doing some

Cheers,
Dan

[AlfA01]

Pic of the car...

Pic...

[Kingmarz]

Did you replace the torque converter? If not that’s the first place I’d look.

[AlfA01]

Did you replace the torque converter? If not that’s the first place I’d look.

Yes, the torque converter was also replaced. I feared the amount of filings and debris in the gearbox would have caused some damage inside the torque converter.

[old Jack]

Have you checked the electrical functioning of the inhibit switch, this is the switch thst sends the electrical signal to the AT ECU that you have moved the gear selector. If this is out of adjustment or failed the trans will either not engage the selected gear or “jump out” of the selected gear whilst driving.

OJ.

[AlfA01]

Have you checked the electrical functioning of the inhibit switch, this is the switch thst sends the electrical signal to the AT ECU that you have moved the gear selector. If this is out of adjustment or failed the trans will either not engage the selected gear or “jump out” of the selected gear whilst driving.

OJ.

Thanks for the reply. I have not checked the inhibit switch. Hopefully there will be a break in the weather these day and I can get under the car and also measure resistance on the switches and wiring.

[AlfA01]

Have you checked the electrical functioning of the inhibit switch, this is the switch thst sends the electrical signal to the AT ECU that you have moved the gear selector. If this is out of adjustment or failed the trans will either not engage the selected gear or “jump out” of the selected gear whilst driving.

OJ.

I finally got some time to work on the Pajero project today. I rigged/adjusted the inhibitor switch. Everything checks out ok with the inhibitor switch and the shift cable. Still the same results.

I decided to drop the pan and have a look at the inhibitor and shift assembly to ensure everything was 100% in order. When I went to pump out the fluid via the cooler tubes there's no fluid flow. Absolutely 0 fluid leaving the tube with engine idling and in Park.

[Scooby]

You did bolt the converter to the flex plate?

[AlfA01]

You did bolt the converter to the flex plate?

Yes, I removed the small transmission supports at either side and the access cover. All bolts were installed and torqued.

[Scooby]

Just checking because the converter drives the oil pump.
So either a relief valve is stuck open (best problem to have) or pump is not working, possibly all the oil drained out of it and hasn’t primed up. (Worst problem to have) If it has ran dry for a while it will probably be buggered.
Not sure about this but do the petrol and diesels run different converters, maybe in length? Converter is pulled to far forward and is not driving the pump now. I remember reading about different bell housings and input shafts somewhere on here.

[psproule]

I finally got some time to work on the Pajero project today. I rigged/adjusted the inhibitor switch. Everything checks out ok with the inhibitor switch and the shift cable. Still the same results.

I decided to drop the pan and have a look at the inhibitor and shift assembly to ensure everything was 100% in order. When I went to pump out the fluid via the cooler tubes there's no fluid flow. Absolutely 0 fluid leaving the tube with engine idling and in Park.

Are you sure the converter has engaged fully in the trans including the pump? Rotate when installing and two distinct engagements as it went in able to be felt - the shaft splines and then the pump drives? How much trans fluid went in?

[AlfA01]

Just checking because the converter drives the oil pump.
So either a relief valve is stuck open (best problem to have) or pump is not working, possibly all the oil drained out of it and hasn’t primed up. (Worst problem to have) If it has ran dry for a while it will probably be buggered.
Not sure about this but do the petrol and diesels run different converters, maybe in length? Converter is pulled to far forward and is not driving the pump now. I remember reading about different bell housings and input shafts somewhere on here.

From what I've understood thus far, there is a difference in stall of the torque converters, but I haven't researched if the two are physically different. Yes, the 4M engine has a different bell housing than the gasoline versions.

[Nab]

I’m sure the petrol and diesel have different bellhousings, one is about 10-15mm shorter (I think the petrol one due to the shorter motor).

[AlfA01]

I’m sure the petrol and diesel have different bellhousings, one is about 10-15mm shorter (I think the petrol one due to the shorter motor).

They are also different in shape. My curiosity is now whether the input shaft of the petrol version is different from the diesel version. I've installed a petrol version gearbox in my diesel Pajero. If the shaft is shorter, It could have moved the torque converter far enough forward that the hydro pump isn't working.

It looks like I will be be tearing it apart again if so.

[Scooby]

When you bolted the torque converter to the flex plate did it have to move forward a fair bit? From memory when I had the auto out of my NM it was about 5mm back and the standard bolts were long enough to thread in and pull it forward. Once again from memory the pump drive is 15 to 20mm long, so if the drive has pulled out you would have had to get longer bolts to pull the converter forward to bolt it up or would have had to lever it forward probably 20 to 25mm.