2003 UZJ100 A750F transmission dying?

[joshAUST]

Well.
I'm back, with another update, FWIW.
I went back to suspecting the transmission for a while... then I booked it in to get new spark plugs, oil change & filter, ATF drain and new gasket & filter, air filter, and the mechanic said number 1 coil was dodgy, and that the transmission seemed good.
Replaced the one coil and, with the ATF refill, new air filter, plugs, etc, its running heaps better.
I think I'll replace the other coils when I can afford it, given its got 230K kms on it, and probably on the original coils.
They're pricey though, for 'genuine' ones at least.
It's still not 100% but its far better, and I suspect replacing the rest of the coils should make it run better.

 

[Spike555]

Thank you for reporting back and keeping us updated.

And now when others with similar issues search the internet they will find this and it just might save them from buying a new transmission.

 

[joshAUST]

No worries Spike.
I hate it when you read through a forum and there is no finish or resolution to it...

The cruiser has heaps more power at take off, smoother shifts, etc, and the noticeable hesitation is gone.
The only real issue now is it seems to have no power at high speed.

At around 100km/h, when you want to overtake, it doesn't want to pick up or increase in acceleration.

I've bought a set of 8 coils, so I'll try to get them in asap and it may help, and keep the new replacement one as a spare.

I did some reading over the weekend, mainly on this forum, and it could be about 8 things, lol.

One bonus is the heater blower, which has never worked since I got the car earlier this year, just started working?
I tested the aircon - cold as ice, heater hotter than a ...something hot.
Nice when things fix themselves.

I'd previously tested the fuse and relay, both tested fine, so I was assuming it was the blower motor, but unlike the FSM, my blower motor is not in an easily accessible location - perhaps because its a RH drive, whereas the FSM is a LH one...and the FSM is for 2004, whereas mine is an 2003 model, which I can't seem to find the FSM for.
Most of the rest of the car matches the 2004 FSM though.

 

[joshAUST]

Back again for another update, in case anyone else is interested.

The car SEEMED to be fine after new spark plugs and replacing the dodgy coil, but I hadn't tested it on the freeway.
Then I headed interstate for a 4000KM round trip.

The car had absolutely no guts at cruising speed (100KM/h), and couldn't climb hills well, on some it slowed to 60km/h!

Cruise control was pointless - a slight rise in the road would make it drop back to fourth gear, any higher - like a slight hill, and the computer would drop first to fourth, then realise it still wasn't accelerating, then it would drop it to third gear, causing the revs to go up to 3000-4000+ revs.
The car also seemed to be hitting every single pothole on the road - it was uncomfortable, to say the least.

I could almost watch the fuel tanks emptying - I worked out later I was getting around 23litres per 100KM!

So, once I arrived at my destination, I pulled out spark plug number one and measured the spark plug gap... It was 0.75mm, when according to denso's website, the Denso ik20? plugs in a 2uz-fe engine should be 1.1mm. So the gap was only around two thirds of what it should be, 0.35mm too narrow.
Re-gapped it at 1.1mm, reinstalled, and then did the same to all the others, and replaced all the coils.
NOW it runs like a dream. It powers up hills, and found on some hills it wouldn't even drop down to fourth gear, just cruised over it in 5th.

I purchased the Denso plugs from my local Toyota dealership in Hobart, who told me they were already pre-gapped at the factory.
They obviously weren't, at least not for a 2uz-fe.

On the trip home, the car ran like a breeze, could hardly feel the road, it was smooth and calm driving.
The fuel economy on the return leg went to 16litres/100KM, which is pretty good with roof racks, luggage, bullbar and two people on board.
From reading, the rated economy is 13ltr/100 on the highway and around 16 in town, so, with the additional weights and drag above, I think 16 is reasonable.

Another interesting thing is the long term fuel trim figures have about halved their distance from zero.
There is still some minor issue, as the computer thinks bank 1 is running rich and bank 2 is slightly lean, which is as it was before the plug gapping and the new coils.
However, instead of one being -15 and the other being +15, they are both now around -5 to +5, well within normal range.

Oh, and now the aircon, which started working, is making a bearing noise, only when its turned on. Still blows cool for now, but will have to look at replacing the bearing, or the whole unit. There's always one more thing to do, lol.

I've included more details than needed, just in case its of use to someone else.

 

[Spike555]

Thank you SOOOOO much for reporting back and giving us the low down.
I am glad to hear your truck is fixed.
I always check the gap on the plugs...always. They fit more than one application and sliding around in the box during shipment they could very well have the gap made smaller.

 

[joshAUST]

Thanks Spike.
When I ordered them from the dealership, they told me they were pre-gapped for my car...
I foolishly mentioned this to the mechanic, and I guess he didn't check.
To be fair, he did do the job at mates rates, and had one of his juniors in to do the actual job, at short notice.
He also believed they'd be correctly gapped from the factory.
It did sound fine, and idled fine, just when it got to high speed it became apparent.
They were all exactly 0.75mm, so I guess they were gapped for a different car.
Lesson learnt. I'll be checking the gaps everytime in the future.
Thanks again.