Torque Converter replacement.... #3

[2000Silverbullet]

So after only 4 years and 8,000 kms my torque converter clutch locked up and failed throwing code PO742

This time instead of opting for a standard Canadian sourced unit, I ordered the ZZP 2500 rpm stall heavy duty unit from the US.
Of course this doubled the cost of the unit due to shipping and exchange..... $600

Now the manual says that the Bonneville for 2000 came with either a 245mm or 258mm IIRC size TC. So I assumed that the smaller unit was for the L67.
NOOOOOOOOOOOO!!!!!!!!
Tore it all apart to find out I needed a new flex plate with dual pattern bolt holes for either 245 or 258 size. Mine had the 258mm!

So had to wait another week to get the flex plate and then re/re again....... he couldn't leave the car on the lift for a week so had to move it in the interim.

Now it takes off like a scalded cat!

The labour rate here is $98/hr that came to $1200.

[95naSTA]

Since the beginning of higher stall torque converters on L67s people have re-drilled their flexplate or used the L36/245mm bolt pattern flexplate. They're weighted slightly different but it doesn't matter enough on these engines.

[2000Silverbullet]

My surprise was having the 258mm instead of the 245mm which I thought was standard for the supercharged version of the 3.8L

So that means the 245mm was standard in the NA 3.8L
I thought smaller equals higher stall. My stock stall speed was 2400 rpm.
Confused!
Are there any gurus left on this forum anymore.......??

[95naSTA]

L67 torque converters were larger from the factory, yes. But the size wasn't common and it was easier to get aftermarket 245mm torque converters.

Equating the stall speed to overall size doesn't make sense since the internals aren't the same.

[2000Silverbullet]

Yes you're right. The internals are different.
I notice it's a lot peppier now. Almost like lower gears.
Revs about 500 rpm higher stall....... 3000 rpm...... it used to be 2500 rpm stall.
Wow it really burns rubber now!!
It also seems to have more power now in the upper rpm all the way to 6000.

One downside is it's running hotter now. The engine temp stays at 170F with a 160 stat but the transmission temp has increased from 170 to 190F
Still lower than normal design temp of 200-220F. Outside temps are cool though at 70F.