My TR magna 2.6 litre auto transmission will only select 3rd gear.
Reverse and neutral function as normal, however remains in 3rd gear even if lower gear selected.
Won't downshift on acceleration either.
Will not go into overdrive.
Have tried selecting power/economy mode but this makes no difference.
Even when vehicle is stopped, still remains in 3rd and engine labours until car gets up to speed.
Thanks for your time.

disconnect the battery terminals for a minuite to reset the computers
reconnect battery terminals

if the auto keeps playing up then you may need a computer unit controller

DIY

you need to by a second hand Transmission controller from the wrecker
to suit your car they often give trouble

location ask at the wrecker

unplug the wiring plugs and reconnect

the mechanical side of the box should be ok if your oil is red and not burnt
and you have forward and reverse gears


link http://www.mitsubishiclubaustralia.com/for...topic.php?t=824]

Thanks for that info and the quick response, Dirty Hands.
I had in mind that it might be the electronics. I have recently had problems with my voltage regulator and the alternator output has been running higher than normal, which has probably put some stress on the controller. That's fixed now.

I've taken out the glove box and passenger kick panel and can only find the ECU there. I've asked 3 wreckers for a price and to advise where to find the TCU ???, all of whom have quoted exactly $275 and have said something like "behind the console somewhere". Quite a coincidence about the price. I might draw some conclusions about this!

If you or anyone else can be more specific about how to get at the TCU, it would save me pulling apart more than I need to.
Another request...can anyone point me to some info on how to perform electrical tests on transmission and/or TCU, which might require only a multimeter and basic tools.
Any advice on how to confirm what the problem is would give me more confidence that I am not wasting my $275.
I've seen mention in other forums of resistance checks and continuity checks.
Thanks again.

posts in link should help


http://www.mitsubishiclubaustralia.com/for...opic.php?t=3284]

the tcu diagnostic plug is near the fuse box on the drivers side

and my best guess is the tcu for the auto is in the area of the steering columm
if you remove the lower plastic surrounds you should be able to see it

Thanks, found it. Tested the TCU and found faulty (no signal on diagnostic pin). Got a new one from eBay. Total damage $65. Plugged it in and transmission is working normally.
I'm totally wrapped. A great forum. Thanks for your help.

good to get feedback when these forums help owners

I have 92 Magna and I just had the gearbox computer go and it did the same thing.That means that your gearbox computer is had it.I found you dont have to follow the same numbers like everyone tells me so.Just get any one out off the same model or near yours.