Driveline bump in new 2.8 auto

[Coo-ee]

Hi All

I own a 2014 GXL Diesel Auto (15K on the clock) and have some strange gear changing habits that I am sure are not good for the car, thumps and bumps felt through the chassis (not audible). I picked out a few excerpts of the posts in this thread as they are all the same/similar things I am experiencing.

Lski - accelerating then removing foot off the accelerator (assume in 3rd to 5th gears), it almost feels like it changes gear when foot is removed from the accelerator and gives a little ‘bump’.

Lordsword - Never does it when stopped, so different from tailshaft clunk thread. When in 3rd, 4th or 5th and foot removed from accelerating, there it is, sometimes...

digys - I have a 6 week old 2.8 auto that does this sometimes. It only happens under acceleration form 1 to 2 or 2 to 3 if i suddenly let go of the accelarator just before it gets a chance to change cogs.

Ozdriver - I am noticing a larger jolt when doing a 'manual' change on the 2.8 auto box from 4 to 3 on a low throttle or zero throttle.

The continuity in the threads seems to be conditions under low to no throttle situations i.e. when the drive-train is lightly loaded. I find it most noticeable when in traffic and start/stopping or moving slowly with the traffic while accelerating and backing off the throttle. (Occurs - often).

Also does the following:

1) When under medium throttle, keeping up with traffic moving away from you, kicks down to 2nd from 3rd with a bump and sometimes a hard thump. (Occurs - often).

2) When you are on light throttle at 60 km/hr, the gearbox 'hangs' on to 4th, like it does not want to change up, and then "releases" into 5th gear. It does that with quite a thump. (Occurs - occasional).

3) When on light/medium throttle, the car has a mild lurch into 2nd and 3rd gears, like a manual gearbox where the clutch is released by dropping your foot off the clutch. Does not flare (no rev rise), just a forward lurch. (Occurs - occasional)

If you pull off from the lights and give it some throttle, no issues, smoothly up through the gears.

The concern I have is with the bumps and thumps, this can't be good for the gearbox, splined shafts, transfer case etc.

I have taken the car to Toyota who reset the gearbox learning programme, greased the tailshaft and told me everything is OK and quite normal for this vehicle.

After the tail shaft greasing things improved but 1000 k's later we are back to square one. I will be chasing them again tomorrow after leaving 2 messages for the service rep with no reply over the last week.

[OzDriver]

Thanks Lski for the feedback. I will monitor it for a few weeks and unless it goes away I will test drive a demo car and see how it compares. The up-shift seems OK but down is not so smooth.

[Lski]

I am noticing a larger jolt when doing a 'manual' change on the 2.8 auto box from 4 to 3 on a low throttle or zero throttle. This does not happen when in fully auto mode. My dealer checked it and did not think there was a major problem (they offered me a drive in a demo car to compare... but I did not have time). I will give it some more running in time and might try another Prado to compare if it does not go away. Has anyone else noticed this?

I haven't noticed this one... just went out to grab lunch and tried up/down shifting between 3/4 a few times - seemed fine.

[OzDriver]

I am noticing a larger jolt when doing a 'manual' change on the 2.8 auto box from 4 to 3 on a low throttle or zero throttle. This does not happen when in fully auto mode. My dealer checked it and did not think there was a major problem (they offered me a drive in a demo car to compare... but I did not have time). I will give it some more running in time and might try another Prado to compare if it does not go away. Has anyone else noticed this?

[grips]

Had a re read. The issue I am having is when you go to reapply accelerator. Different issue. My mistake.

[RyanIAm]

Mine is in for 10K service today and i've asked my dealer to have a look. I described it as a slight flaring on downshift. We will see what they find.

[grips]

It's not the tail shaft issue. That happens when the car is stopped. I've had the tailshaft replaced multiple times and greased more times than I can remember. Fixed the problem for about 20km before it returned.

[raydes]

Put some grease in the driveshafts, makes sure all are done, if the noise goes you know its the drive shaft. I believe when toyota build the drive shafts they put a small amount of grease on the parts for assembly only, the dealer should grease the joints before delivery , I dont think they do thats why so many have problems with the drive shafts.

Not a dry driveshaft slip yoke, is it?

[digys]

I've got a manual 2014 3L and it does what you're describing on occasion also.

Never does it when stopped, so different from tailshaft clunk thread. When in 3rd, 4th or 5th and foot removed from accelerating, there it is, sometimes...

I have a 6 week old 2.8 auto that does this sometimes. It only happens under acceleration form 1 to 2 or 2 to 3 if i suddenly let go of the accelarator just before it gets a chance to change cogs.

[cuda]

Went for 1000km service and complained of the same issue. After some investigating they came back with the tail shaft was dry and no lube. Must say it seems to be driving far better now will see if it continues. It occured when down shifting in the auto or even sometimes when the converter locked. They did apologize saying it should have come from the factory lubed. Dont know if it was just me but seems like the fuel consumption is also a little better. Managed 7.3l /100km while doing a 100km/h on the freeway after lubing.

[brundah01]

Just read this thread, IMHO may be two different issues mentioned here?


1. An older vehicle tailshaft wear issue as mentioned.

2. New vehicle maybe just the slight "thunk" when the converter lockup disengages i.e. when stationary at the lights after being above TC lockup?

Just a suggestion.

[grips]

I've got 09 Petrol Auto that has been doing it for a couple of years. Had the tailshaft changed three times. Eventually after they couldn't fix it claimed it was an adaptive learning function of the gearbox. The clunk in mine is significant.

Toyota asked me to take it to a different dealer to have assessed again. Dealer said they would contact previous dealer and get back to me. Never did. WHen I contacted Toyota directly was told the job card was blank. Ie they had no intention of doing anything.

Was told I would get a call back. Never did. Rang again asked to escalate. Told manager would call me back. Never did. Called again. Eventually got manager to call back. He promised to follow up and call me back... never did Basically Toyota are ignoring me hoping I will go away.

It's with fair trading now and if that doesn't get a result looking at what legal action I can take.

Having it recorded early in the warranty means nothing. Toyota will fob you off until warranty expires. It's a shame otherwise a great car but the customer support and warranty is worthless.

Moral of the story is don't do what I did and be reasonable and get strung along forever and a day.

From what I've been able to discern it's most likely a problem with slack in the drive train. I've asked Toyota to test tolerances on the drive train but they refuse.

[Riv39]

Nah doesn't sound like ye old tail shaft clunk to me. More like a down shift clunk of some sort. Maybe a firmware update is in order for the trani.

[lordsword]

I've got a manual 2014 3L and it does what you're describing on occasion also.

Never does it when stopped, so different from tailshaft clunk thread. When in 3rd, 4th or 5th and foot removed from accelerating, there it is, sometimes...