All,

Here'e the vehicle:

1995 Tacoma Limited
3.4L V6
Auto trans, I believe the A340H

Sounded like a bad catalytic converter at first, but the noise came from the bell housing, directly under the torque converter. I pulled the inspection plate and to my surprise I found the flex plate to be cracked almost completely around, close to where it bolts to the crankshaft.

I have the '95 Toyota service manual for the truck, and it shows all the components that need to be replaced to remove the trasmission...including the front differential.

I do have the tools and the mechanical experience to tackle the job, but this is obviously going to take some time. Has anyone done this? If so, how did it go? Do I really need to completely drop down the trans?

Any ideas WHY the flex plate would crack in the first place?

Thanks!
Dave

Can you reach directly under the flex plate pretty easily? If so, here's what I do at work all the time...

First remove one of your bellhousing bolts, go to the hardware store, and find (2) 8-10 inch long bolts with the same threads as the bellhousing bolt.

Remove the inspection plate, and undo all of the flexplate to torque converter nuts/bolts. Put a trans jack on the t-case, with a ratchet strap holding it onto the jack. Remove the bellhousing bolts. Install the long bolts in the top 2 bellhousing holes. Remove tranny cooler lines, 4wd wires, and all other wires connected to the trans. Remove the drive shafts from the t-case and let them hang. Undo the t-case crossmember at the frame.

Now slide the trans back as far as it will go with the new longer bolts. You should now have enough room to reach up in between the trans and flex plate and remove the flex plate bolts. You will need a friend hold the crank on the front of the motor with a wrench or use a flex plate teeth holder. Or if nobody is available you might be able to jam the wrench in between the frame.


Saves some time not having to drop the trans and then put it back up. Make sure to use a torque wrench and re-torque the flywheel bolts to spec. When your done just slide the trans back together. It will go back easy since you have the longer bolts still attached.

How many miles do you have on your Tacoma?

Some T100 guys have said their flex plate has cracked. That was the first truck with this engine and transmission, so they have the most miles on them. A majority of the guys that crack the flex plate seem to have more than 200K miles when it goes. Here's a link to one of those threads on the T100 forum here. Click on the links in that thread for other threads and pics about it:
http://www.4x4wire.com/forums/showflat.php?Cat=&Board=UBB78&Number=1060357

Thanks for the replies, guys! Hopefully I can start tearing into it this week.

BTW, the truck has 143k miles on it.

<img src="/forums/images/graemlins/cheers.gif" alt="" />,
Dave

Suppose I should update this, as the truck has been back on the road for two months now... <img src="/forums/images/graemlins/smile.gif" alt="" />

The job wasn't terribly difficult, just time consuming. I followed the service manual, however I found that the fan and shroud did not need to be removed, nor did the front differential (it did need to be loosened, but the CV joints did not need to be separated.) I also bought one of those transmission jack adapters from Harbor Freight, which worked out very well. Man, that transmission is huge!

I found I had plenty of room to change the flex plate by moving the transmission back about 1 foot after separating it from the engine. The transmission adapter features a tilt adjustment, so repositioning it back against the engine went fairly smoothly.

It's still a mystery to me why this thing cracked to begin with. All six torque converter bolts were tight, and since the bell housing is aligned to the engine with dowel pins I don't think there was any misalignment there. I suppose the plate could have been defective, but I haven't seen or read about any other Tacomas with this problem... <img src="/forums/images/graemlins/confused.gif" alt="" />

Here's a photo of the converter. After removing it I discovered the crack to be worse than shown...there was actually about 1/2" left before it broke completely:


Happy Holidays!
-Dave

Thanks for posting the followup!

You got me thinking about this.... Does anyone know if there are any possible replacement parts that might be stronger than the original to reduce the likelihood of this happening again? Does anyone know if Toyota sees this as a problem so just maybe they are making replacement parts thicker or stronger now? Or just maybe a Tundra flexplate for the V8 might still fit for this engine/transmission, assuming it might be stronger? Or maybe it just doesn't matter since it's assumed the engine or vehicle might not last to see another 140K miles. <img src="/forums/images/graemlins/pfft.gif" alt="" />

I did a little more web searching on this and found one person on another forum with a 4Runner where the flexplate died after only 120K miles. The Tacoma in this thread and one other person with a Tacoma had it die at around 140K miles. And multiple T100's at around 200K miles. Ugh.

Did you ever find out what made the flex plate crack?
I also have a 1995 Tacoma 4x4 v6 with 166,500 miles. I have replaced four flex plates in the last three years.
First, one went at about 145,000 miles and since then one about every year. Toyota has never seen a problem like this
and is giving me no help. I'm in the process of changing one tomorrow.

FOUR flex plates? Holy cow. I can't believe this seems so rare. Do you so any towing or 4-wheeling? I tow a 2500lb load about once a month on average, but I do not take the truck off road.

Unfortunately I have no idea what the failure mode was with mine. I'm assuming yours cracked like mine in the above picture?

Thanks for the input.

4 flex plates? Instead of changing them, maybe you should find the route of your problems!
Bad TC? Bad harmonic dampener?

I have a 2002 Tacoma auto double cab and I too have a broken one, per the mechanic, at 112k. This is insane! I asked my mechanic about the noise and he said it was likely a cracked flaxplate. He said that I could still drive it though, and it broke on the road. The truck is not drivable, so I will have to tow it to the mechanic.

To the OP: He charges $80 an hour. How many hours did it take you to replace? I am just wondering how big my bill will be.

Also to the OP: Did you change the trans fluid during the regular service intervals (every 30k)? Did you just drain it or did you use the special equipment to flush up to 90% of it? I wonder if this might have something to do with my failure...I need to ask my mechanic how he serviced it. I do not put any kind of regular load on the car and I have never towed anything so this is weird and disappointing to me.

Let me know if you would!