if this is a known problem in this A340F transmission (from the Tundras)...I have to ask why hasn't Toyota had a recall or a goodwill gesture repair on 4Runners?

My '02 has 113K and so far so good. (but it's definately not making me feel good seeing those pics!)

I thought Toyota's were supposed to be reliable?

-B

 

They are reliable. An Internet forum is not a random sample. You end up with folks who obsess over vehicles and/or have problems. You want unreliable? There's about a dozen out there I wouldn't touch with a 10 ft pole.

MadCityRich
2002 4Runner Ltd.

 

can't agree with you more MadCityRich (trust me...I would never, ever, EVER buy another volks!)

thats why I switched to Toyotas (bought my wife 2 corollas and have been the greatest little cars with no problems)

and was very impressed Toyota when they recalled my truck for the ball joints...that wasn't a cheap repair.

but...

if this is a KNOWN problem from the Tundras...it's still not making me feel too good knowing that I may be sittin' on a time bomb?

-B

 

For those who have had the failure and taken the transmission apart, Are these the "thrust washers" that you have found broken? If so, was there any sign of a bearing having been between them?

 

I did not watch the teardown but will get an answer for you.

 

Yes, there should be a thrust bearing between the two races and there was probably nothing left of it, but it's very hard to say if the planetary teeth failed and then those made their way to the bearing and destroyed it as a result of the gear failure or the other way around. All it would take is one small piece of a planetary tooth to get wedged into the thrust bearing and it would completely self destruct (as you saw in the pics from Randy?„). From all indications that I have seen, it is the planetary teeth that fail first and cause the chain of destruction we've all seen in countless pics, not the other way around.

What it would take would be someone like yourself who has not yet had a catastrophic failure but has found pieces of gear teeth in the tranny pan to do a teardown and rebuild BEFORE the tranny blew up completely. If I were in your position I would just find a used tranny to install and then tear down the old one to see what happened. Sometimes you can find tranny shops that will buy the old one as a core for rebuilding so you can make some of the money back. It's only a matter of time before driving with the OD off comes back to bite you.

 

Yeah - the OD off deal could come back to bite me in a big way, but at worst I'm out a tranny that already has issues. Anyway, the failed parts won't be any worse for wear as long as I keep the button pushed, so they can still be helpful in the diagnosis. I've got 700+ miles on it without using O/D since I dropped the pan and is hasn't missed a beat. Actually, it shifts very nicely. The only two things that annoy me are the fuel economy and that the torque converter locks up a bit earlier than I'd like it to in 3rd under light acceleration.

Anyway, back to getting smarter...
I spent some quality time at the parts counter this afternoon. There are some parts in this tranny that are exclusive to 2001 & 2002 models so swapping for an older unit isn't an option. 2003 or later trannys are out for the same reason. At some point in the 2002 model year, the bearing stack betwen the carrier and hub changed from a race - bearing - race configuration to a race - bearing with integral race set up. Also, the planetary gear assembly crosses to a new part # requiring the new bearing design and a new ring gear hub to be used with it. Although there is nothing confirming it, I'm guessing that the upgrade to the planetary and the bearing change had to be done at the same time in production.

Randy, in an attempt to get a grasp on when the change might have taken place and since your 4Runner is a 2002, could you let us know when your truck was built and if you still have the tranny, the #s on the serial plate from it? Anybody know how to read the Aisin Serial #?

 

1700 miles without overdrive since I dropped the pan and it hasn't missed a beat yet - This may become an experiment in how long can it last...

 

That is a good question and one I would also like answer to. This is definitely a known problem, but it is more obvious in tundras since they put out more power and more people use them for towing. They solved the problem in '03. I have an '01 tundra and although I haven't had any trouble yet, I am afraid that someday I will. :fingerscrossed:

 

Interesting, keep us posted.

 

Uhh... i dont have time to read the whole thread, but were you towing WHILE in overdrive? Because that right there would be the cause of your problems. NEVER tow in overdrive. (esp with an auto)

 

I guess I wouldn't have a problem with saying its the owners fault IF there was a big warning label somewhere "WARNING DO NOT TOW IN OVERDRIVE OR CATASTROPHIC TRANSMISSION DAMAGE MAY OCCUR". But really, these are automatic transmissions controlled by computer, if the OD can't handle some towing the computer should drop out of OD when the torque limit is exceeded IMHO.

But, I don't guess that warning label would go over too good on the show room floor, would it. I can just see some redneck wanting to tow his boat to the lake saying what do you mean...I'm suppost to drive for 2 hours to the lake in 3rd gear? Hey, do you guys have any trucks with a tranny strong enough to handle towing my bass boat?

 

Not only is there not a big red warning label, there is no mention not towing in O/D in the manual. I looked in the O/D instructions as well as the towing instructions and found no mention of this. Personally, I can't see the difference between going up a grade without a trailer and driving relatively flat terrain with a trailer. Either way, I can lug the motor a bit in O/D without applying enough throttle to kick it down into 3rd.

...and yes, I did tow about 1500 lbs (including trailer) on a dozen or so occasions at speeds up to 80MPH both with O/D on and off. If it wanted to stay in O/D, I left it there. If it wanted to drop to 3rd, I turned O/D off so it wouldn't be hunting.

 

Anyone have an update on this?

 

I didn't hear back from anybody regarding the transmission and vehicle build dates. The more I looked around, it seems to be most likely a thrust bearing cage failure allowing the rollers to get into the planetary & ring gears. Design changes were made to address this and maybe other issues.

I gambled on a transmission off eBay from a 2001 with 59K. I haven't had a chance to drop the pan on it yet, but the previous owner said it shifted fine and made no noises. The fluid that came out of the converter looked a tad dark, but didn't smell bad and had not shiny bits in it. I got the transmission with transfercase, front drive shaft, transfer shifter and a 16" alloy to match my other 4 for $500 + 12 hours of driving and $100 in gas to pick it up in Chicago. I figured for that price, I couldn't pass it up.

...and I'm now at 2800 miles with O/D switched off and no issues.

 

I'm not exactly clear, did you normally tow 4000lbs with overdrive selected on?

 

Where are you located? I might have a tranny or two for you!

 

Coming up on 5000 miles with the O/D turned off...

 

are the trans parts out of an A340H interchangeable with the A340F.... (i know the transfer case parts arnt... but what about the actually transmission parts?)

 

Well I made it 7000 miles wih no issues with O/D turned off. I swapped the transmission this week - what a pain! There is not much room to work with at the front of the tranny; getting to the converter bolts was a real treat!

When I have some spare time, I'll tear down the original tranny and have a look.

In the mean time, I'll be enjoying a 4 speed tranny and contemplating whether or not I wnat to tow in O/D.