General Motors 8L90 mechanical operation and powerflow

This video is part two of a seven part series on the GM 8L90 transmission. In this video, I cover the mechanical operation and powerflow. I describe the transmission identification, gearset components, clutch assemblies and I describe powerflow in each gear.

Here are the other videos in this series:

8L90 Rebuilding Particulars:
8L90 Modifications and Tuning:

Special thanks to Precision International, TransGo, and Sonnax for providing me with product to use in these videos. Also thanks to KB Cores and AA Midwest for providing me with a few 8L90 cores at a good price!

[hyeeagle]

Thanks for teaching me and who ever want to learn. I tell you what. I think both guys in the video are very smart not only one and hard workers.

[michaeltaylors]

What is flaw in these ? Meaning what is the defect(s) that causes these to shudder, shake your guts violently, pop out of gear, and destroy their torque converters ? Is there a part that can be swapped, modded. Is there a new code ? 2019 Silverado 5.3 . I had the Mobile synthetic fluid flush and new torque inverter installed by GM. Great video !

[VanTheSheepDog]

I would lovecto see you all tear down and rebuild a GM 10L90!

[gdtruckern]

Awesome video very helpfull and educational !!! Thanks.

[ericcindycrowder]

So…this GM 8 speed doesn’t use any Simpson or “compound” style planetary gear sets? I think the ZF 8, which is such a common box for multiple different automakers and vehicle brands use compound planetary.

[kodi]

I am on my 21st of these and I am finally stumped on one that has a 3/4 delay / reverse delay i cant seem to find the problem. Other wise the trans works great. I have tried everthing. WTF? I am suspect to SS5 in the valve body but I am not sure.

[johndirksen]

I see on the shelf you got a ZF8HP .The 8L90 is based on the ZF8HP, the powerflow is exactly the same. GM only switched the position of the first and third planetary gearset. An advantage compared to the ZF8HP is you don't have that long outer shell connecting the planet of gearset 1 with the ring of gearset 4, because gearset 1and 4 or now next to each other.

[traildisc]

Why did u take down 8l90 overhaul video down

[ابوفهد-يزص]

Teachers, what is the Mercedes W5A580 transmission class?

[brandonseals]

ive build all (except 10 speed)... i still say, gimme a 4l80e any day in my truck...

[theskyisfalling_]

What will happen if said 8L is "accidentally" filled with Dexron IV instead of HP. Asking for a friend 👀