GQ Auto no 3rd or 4th gear

[MarkGQ]

Hi Gang, well heres my very first post here. Im having trouble with my auto in my GQ 89 model, no 3rd or 4th gear, 1st and 2nd only. Ive done the diagnostics and it says (inhibitor switch, poer shift switch, kickdown switch or idle shift switch circuit is disconnected or the control unit is damaged). ive changed most of these and still nothing??? also my book dont say where the control unit is or what it looks like. any help would be appreciated.
cheers Mark.

[growler2058]

Gday mate welcome aboard someone no doubt will have an answer for ya soon

[Bigrig]

Hey mate - when you say control unit, do you mean the ECU?? If so, it's behind the panel in the drivers side footrest (beside the fuse box) - but sorta kinda think you're not referring to that, as you would have had to connect to it to do the diagnostics I'm assuming ... not sure as I'm certainly no transmission expert, but sounds like some sort of 'limp' mode being implemented by the control unit - which could mean transmission is stuffed, but could mean an electrical issue (or anything in between) ...

One for Tony and the more technically minded me thinks ... hang tight mate, someone will be along to assist/offer suggestions!!

[Yendor]

Hi Mark and welcome to the forum.

It sounds more like a mechanical problem then an electrical problem to me.

Have you remove the auto pan yet? any foreign material sitting in the bottom of the pan?

[Ade]

Hi Mark..
From what I have gone through, it might be a worn brake band (if everything else are checked and o.k)..and if it is so, you need to get it overhauled. My auto box problem was, it skips 2nd and didn't shifted into 4th at all. It will stay in 1st if I shifted it into 2nd range and so did in 1st range. Have my box stripped off apart to found out the brake band has completely worn out. Symptom..lots of metal particles sticking to the magnet inside the oil sump. In my case, about the size of my little finger sticking roundly to the magnet although my ATF color looks normally clean.

[MarkGQ]

Thanks guys, I havent removed the pan yet as everything ive read seemed to lean towards electrical untill now lol.

[Ade]

My odo clocks around 290k km when the box given up. I had it cooked once to 140c before having two ATF cooler installed, never reached 95c ever since. But like what our guy Tony-YNOTsaid, I've been on a borrowed time (maybe like 30k-40k km) ever since I had it overheated. What about yours Mark? Any temperature issues on the motor or the box before?

[MarkGQ]

Hi Ade, hmmmm ive only just bought this GQ and i bought it with the problem so I have no idea what its been thru.

[Ade]

Whats the odo read..?

[Peacemaker]

Mate I've got the same problem only mine goes away after it heats up a bit. I am leaning toward the auto temp sensor. You can trick the auto trans computer by soldering a resistor on line to make the comp think the trans is warm. I'll try find the article and post a link for you.

[MarkGQ]

Peacemaker that would be great if you could find that link, much appreciated.
Cheers Mark.

[da' maverick]

mine just lost 4th. in my case its the torque converter. check the oil for any black specs. if you find any stop driving it. around 500 for new converter