Car's auto transmission won't gear down well: any ideas on root causes?

T

tdh78au

Guys,
In a bit of a pickle with the missus' car. It's a 10year old RAV4 and having it's first ever issue. Basically the auto gears won't change down and this causes the car to start shaking / vibrating rigously when slowing down.
Have been to a toyota dealership and they have recommended changing the ECU at cost of 1.2k :eek:
However they cannot give me guarentee that this will fix the problem. I got them to do a transmission service (just in case burnt oil type scenario) .... car worked ok for couple of days .... and then the same problem again.

Any suggestions / thoughts from the more auto knowledgeable folks on this forum?

Take a gamble with 1.2k? *gulp*
 
ECU?

how about a good bluddy service?

have you ever had the transmission serviced since you've had it, other than an oil change?

get the thing flushed and see if the bands can be tightened. you may find that the car is changing down, but the bands on the drum (holding your friction plates) are loose and are binding, grabbing the drum causing the shuddering. if it's been happening too much then the bands might need replacing, but generally Toyo trannies are easy to get at with the bottom pan off.

it alsmost sounds like it's not changing down gear and wanting to stall. what happens when the car is stopped? does it take off okay, or on kickdown does it slip?

if it's a CVT (constant variable transmission) then all bets are off.

this is a common thing for cars left in "D" when standing at lights etc. always shift to "N" to avoid this happening.

worst case scenario? get a better second hand transmission from a wrecker / trading post and fit it up. you could rebuild it but i doubt you'd get much change out of $1200 - and steer WELL CLEAR of a dealer - THEY are the cowboys, not your average transmission place.
 
A mate's RAV4, 2001-2002 model sounds about right, had the same thing - the auto wouldn't change gears properly. He had the transmission rebuilt (over $1k) and then the ECU replaced (again, over $1k). So your quote seems about on par. He sorted it finally, but it was a painfully expensive repair. You might save a bit on labour by having them both done together.
 
Ausprop said:
trade it in, who knows what will be next.
Click to expand...

On our tribute (All wheel drive....) the transmission went just outside warrantee.

$5000.00 that cost to replace.

First it was a little rattle noise ocassionally coming from the transmission, then it was a rattle noise coming from the transmission all the time, then it started to behave like the OP's Rav4. It struggled to make gear changes.

In an all wheel drive vehicle the transmission is a pretty complex bit of kit. In future I will only ever buy 4x4 or 2 wheel drive cars and steer clear from AWD alltogether. even the all wheel drive transmission specialist seemed to think they were a stupid idea due to how busy he was. That said he did mention that Subaru were one exception where he hardly ever got any in at all.

If ever I hear a little rattle noise coming ocassionally from the gear box I am going to follow your advice and trade it in while it still drives.
 
I love our CX7 but am told the turbo has a habit of going and they are $15k to fix. they are also AWD and your story has stressed me even more!
 
Aaron Sice said:
ECU?
how about a good bluddy service?

have you ever had the transmission serviced since you've had it, other than an oil change?

get the thing flushed and see if the bands can be tightened. you may find that the car is changing down, but the bands on the drum (holding your friction plates) are loose and are binding, grabbing the drum causing the shuddering. if it's been happening too much then the bands might need replacing, but generally Toyo trannies are easy to get at with the bottom pan off.
Click to expand...

Thanks for your response Aaron. The car has been serviced regularly; and the last transmission service did include flush, etc.

Aaron Sice said:
it alsmost sounds like it's not changing down gear and wanting to stall. what happens when the car is stopped? does it take off okay, or on kickdown does it slip?
Click to expand...

Stall guess is correct. If I let it be (i.e. don't interfere with the shaking while slowing down) then hear a bang and then we apply the brakes immediately. Have never really let it go all the way to see what happens.
It takes off ok .... gear change up is not an issue yet.


Aaron Sice said:
worst case scenario? get a better second hand transmission from a wrecker / trading post and fit it up. you could rebuild it but i doubt you'd get much change out of $1200 - and steer WELL CLEAR of a dealer - THEY are the cowboys, not your average transmission place.
Click to expand...

No issues with the transmission yet .... only the ECU (well based on the diagnostics from dealership. Amazingly googling around I've found out this is actually a known issue in the 2001-2003 RAV4's ... and in the USA Toyota have extended their warranties on ECU's + Transmissions to 10years + 150k miles and re-imbursed all customers who incurred out of pocket costs. Unfortunately no such service for folks down under!!!
 
softmonkey said:
A mate's RAV4, 2001-2002 model sounds about right, had the same thing - the auto wouldn't change gears properly. He had the transmission rebuilt (over $1k) and then the ECU replaced (again, over $1k). So your quote seems about on par. He sorted it finally, but it was a painfully expensive repair. You might save a bit on labour by having them both done together.
Click to expand...

Haven't had the recommendation to get the transmission fixed/replaced yet. So far it's only the ECU. Fingers cross this fixes it enough for me to offload the car.
 
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