Using 4l80 in Humvee with LS?

[sail78385]

Ive exhausted my keyboard trying to figure this out. Can the factory 4l80 in my Humvee be used with a LS engine, such as a Lq9? Anyone gone this route and used a Holley setup with the gauge pack/screen from Holley? If this is even possible is the stock humvee torque converter ok or does it need to be swapped?

 

[TOBASH]

Your HMMWV torque converter will probably have the wrong stall speed.

 

[Mogman]

They make adapters to be able to use the legacy transmissions on the LS motors, the crank to rear engine flange depth is different, and as TOBASH said you should use a gasser torque converter.
The info is not hard to find.

LS Engine Swaps: Transmission and Clutch Guide

LS SWAPS: Transmission and Clutch Guide Includes in-depth instruction and photos. Covers all the criteria to consider when starting an LS swap project

www.cartechbooks.com

.

 

[Mogman]

I had to do the reverse when I installed a 6L80 behind the Detroit engine, I had to use a spacer between the bell housing and engine rather than a spacer between the torque converter and crank.

 

[TOBASH]

There is a guy doing this swap on the H1/HMMWV forum on:

The Hummer Network

Community platform by XenForo®

hummernetworkforums.com

https://hummernetworkforums.com/threads/project-hercules-lt-engine-swap-with-8-speed.247965/

 

[Mogman]

Here is a link with some visual explanations, IIRC you will need a conversion flex plate and a crank extension, the crank extension gets the 4L80 torque converter correctly spaced into the transmission.

All about Flexplates, Converters, Transmissions and Spacers - LS1TECH - Camaro and Firebird Forum Discussion

Automatic Transmission - All about Flexplates, Converters, Transmissions and Spacers - When installing a different (non-stock) transmission there is often confusion over what flexplate to use and whether a spacer is needed. When swapping an LS engine into a custom Hotrod, there is even more...

ls1tech.com

 

[Mogman]

There is a guy doing this swap on the H1/HMMWV forum on:

The Hummer Network

Community platform by XenForo®

hummernetworkforums.com

https://hummernetworkforums.com/threads/project-hercules-lt-engine-swap-with-8-speed.247965/

If he is using an 8 speed than that is not a gen I or II transmission and would have no bearing on this subject, not a member so I cannot look.
EDIT, actually I am, no this conversion has nothing in common with the OPs post.

 

[sail78385]

Thanks y’all, back and forth on fixing up the 6.5 or getting a LQ9/LQ4 6.0. I appreciate all the info, I’ll look into those other pages.

 

[TOBASH]

Perhaps I posted the incorrect thread…. Plenty of people go gasser.

 

[TOBASH]

Some of the original H1 were built with Chevy engines. They are called gassers. Many people throw in Chevy engines. Discussed here and that other forum.