Auto transmission not shifting in D (resolved)

Gday all !

My beloved '95 Diesel has begun playing up (again).

A few weeks back, I went to accelerate as normal and noticed the revs climbing quite high without gaining much speed. It seemed the car wasn't shifting into gear 1 while in Drive. This continued through the night and the next day, then periodically over the next week (it wasn't consistently doing it every drive, sometimes it would be after 20 minutes or so, sometimes not at all). It would take off as normal at around the 30km/hr mark, leading me to believe it wasn't shifting below 3rd gear automatically. It also seemed a bit shifty changing into the higher gears (4 & 5). It would take off fine if I put in 'Low' gear and go from there. After about 10mins each time, the O/D OFF light would begin continually flashing.

I took it to an auto transmission place who were unable to diagnose a problem via the computer as my older vehicle probably didn't store errors, so they gave it a service and said I'll more than likely need a new transmission put in. I managed to take it back when the O/D OFF was flashing, and they were still unable to diagnose the problem - as if the computer wasn't talking to the scanner, however, they could scan the engine for problems.

This then lead us to believe it may be an electrical problem, not a mechanical problem with the transmission. I did some googling and have found on this, and other forums, similar problems to this have happened in the same / similar vehicles. I have also noted that, after the service, it hasn't been able to take off in 'D' gear at all.

A common problem I have found that it could be an issue with the transmission solenoids, however, the mechanics said this would more than likely show up on the computer scan. Other posts say it could be a faulty/dodgy wire &/or connection somewhere in the line.

As we were unable to diagnose a problem, I was leaning towards getting all the transmission solenoids changed and seeing how we go from there. But I thought posting here first might shed some light - so I'd love to hear from you guys on what you think I should do ?

If it's worth anything - I have already dealt with the faulty capacitors on the ECU - but is it possible that there is more or the transmission computer now has this problem ?

Cheers for any and all help,
Brock

Hi!

First you'll need to identify the model number of your gearbox (on the gearbox or vehicle plate under the passenger seat) so internet searches turn u any known problems.

Also is the fluid level correct and what is the fluid colour when the dipstick is wiped on a white cloth or paper?

There's some highly detailed youtubes on some Toyota gearboxes BTW, just find the model and have a look, As for the ECU - yes I think it's possible it could be ageing, I can't recall if I looked in mine but certainly worth a look, mine was under the centre console in a little rack, so easy to slide out and look at.

I noted you said 95 diesel so possibly the 1kz-te engine and Aislin A340 something gearbox. I have read you should be able to hear the solenoids click when activated if you unplug the plug to the gearbox and enegize them. I never managed to find the wiring diagram but with white or while/black-stripe generally being earth you could use a multimeter to see if you can find 3 or 4 plausible resistances.

Thank you for your response GPW !

This issue has now been resolved. For those interested;

After some research on this website and in particular the follwoing post;

https://www.pirate4x4.com/forum/toyota-truck-4runner/587521-a340-transmission-issues-faqs.html

I recongnised very similar symptons - not shifting from 3rd to 1st and 2nd (unless it was automatically put in L and 2) and the diagnostic computer not returning a code (due to it being a mechanical failure instead of electrical).

Put in into the local tranny shop to get the solenoids replaced sure enough, #1 was completely broken. I got all 3 changed in case the others were on the way out and she is running better than ever.

Great news!!

stuck in low gear...............only at night? WTF yes the headlights are used at night............... headlights on causing aVOLTAGE DROP from thin foil type wiring on the back of the dash board!

how would you ever pick that! all good