Flexplate keeps cracking - 02 Tacoma

Alright yall this is my first post but I would appreciate some help on this one.

I have an '02 Tacoma SR5 w/ the TRD Off Road package. About a year and a half ago, the flexplate cracked and had to be replaced. Every 8 months since then, like clock work, it has been cracking. I'm now getting ready to replace it for the 3rd time. I'm thinking whatever issue caused this to happen the first time, has never been solved by either mechanic I took it to.

Do any of you have suggestions on what the issue might be or have you had experience with this kind of problem? Any help is much appreciated.

 

Something is shock loading the flexplate maybe? Does the tranny has a "shift kit" in it which would firm up the shift points and might transmit a shock wave into the plate every time it slams into another gear. Best solution, no matter what the cause, might be to cryo treat the flexplate.

 

Torqued in a bind during installation?

 

How's the starter? Does it hang up and the solenoid maybe doesn't retract the starter gear back in. Maybe jamming the flex plate?

 

Missing dowel pins , bellhousing run out , crankshaft end play , loose bellhousing bolts . bad universal joints , broken transmission mounts , incorrect flex plate used , missing flex plate shims . incorrect assembly as mentioned above by Bill .
Converter pilot shaft broken and stuck in crankshaft
There are all kinds of issues that come into play here . How does the transmission upshift and downshift ? Any vibrations ?

 

Good to know about this issue. Any idea of they can be treated for added strength, since it seems I can't find any aftermarket options?

 

Like Bill mentioned, there is a proper torque sequence to follow to tighten the flex plate to the crankshaft. And like gearcruncher said, the flex plate does have a spacer/shim and maybe they didn't install it. There's also a chance they didn't gradually torque the bolts that hold the flex plate to the torque converter and maybe it's not balanced. I helped my buddy Sean replace his auto trans recently and I gradually tightened the flex plate/torque converter bolts to spec in many passes as Sean turned the crankshaft bolt for me. When it's not balanced and has a ever so slight shimmy to it, it's eventually going to fatigue and break. But, like gearcruncher mentioned, that movement could be caused by other things as well.

 

10tacosr5
The first time I replaced it, didn't notice anything from the starter. Now this last time it was replaced it started making this screeching grinding sound every time you start it. Its been doing that the last eight months since then.

 

It sounds like the starter gear isn't lining up right with the drive plate gear (aka Flex plate gear). Is your starter an OEM Denso starter or is it an aftermarket replacement? I'd check to see if the starter is fastened tightly to the bell housing. If the starter is OEM and tight to the bell housing, something isn't right. You should not be hearing a grinding noise. When you got your rig back after the last drive plate replacement and noticed the grinding noise every time you started it, did you go back to the shop and ask what's up? If the mechanic didn't install the front drive plate spacer (this is the one between the drive plate and crankshaft) this would put the flex plate in the wrong position. There's also a chance he swapped the spacers. The front spacer between the crankshaft and drive plate is different from the rear spacer that goes between the bolt heads and drive plate. Whether the front spacer is missing or the wrong one could explain why the starter gear is meeting up right with the drive gear.

I looked up the parts numbers:
The front spacer for a V6 is #32116-32020
The rear spacer for a v6 is #32117-50010

Here's a link to a parts seller where I figured this out:
http://parts.lakelandtoyota.com/sho...&ukey_driveLine=6762&searchString=drive plate

VZN18# is for V6 engines and RZN18# is for 4 cylinder engines.

 

A bad torque converter turned out to be the problem. Hasn't happened again since we replaced it!

 

Good to know just what the cause was

 

Awesome to hear man!
As I was re-reading the posts above asking about that and the different replies and after seeing ZUK suggestion of something shockloading the flexplate, the torque converter popped into my head.
Glad you reported back and glad it's up and running the way a first gen taco should be

 

I saw the date and was bummed I couldn’t answer you. I had the exact same problem, my torque converter was warped. The shop used a runout gauge and it was completely messed up and uneven, like a valley.

For my second flex plate I made it a whole 200 yards from the shop before it broke again