8L90 Torque Converter Upgrade

[Foary]

I have a 8L90 transmission and looking to swap out the stock torque converter (which has issues) with a built TC.

 

However, there seems to be no simple answer. I have a 2018 Silverado 1500 High Country 5.3L. It's all stock, no modifications.

 

1. Which diameter do I need for mine? Is the 258mm stock size? 
2. Which stall should I go with? 
3. Do I need a billet flex plate from Circle D? My engine is 5.3L

 

I don't have a transmission shop in my area, and my local Chev says they won't install an aftermarket TC unless I buy it through them, and they want $400 extra for a Circle D. This is the converter I'm looking at: https://www.circledspecialties.com/collections/converters/products/8l90-hp-series-258mm

 

The truck is my daily, I just want to fix the torque shudder issue from factory.

[rav3]

Can we assume you have had the upgraded ATF SB done.

[SeekAndDestroy]

On 12/9/2023 at 5:45 PM, Foary said:

 

1. Which diameter do I need for mine? Is the 258mm stock size? 
2. Which stall should I go with? 
3. Do I need a billet flex plate from Circle D? My engine is 5.3L

1) Yes, that is the correct size

2) Get the stock stall. If you increase the stall speed you may not like how it drives. You will also need a transmission tune

3) No, you don’t need it with stock power