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.

 

[Anvil Motorworks]

if it’s a 6.5 NA I’d pull it out and swap in a LS with the 4l80. With a standalone setup you shouldnt have any issues just need to figure out the correct flexplate and converter.

 

[TOBASH]

Welcome Anvil!

 

[Anvil Motorworks]

Welcome Anvil!

Hey there Tobash!

 

[EVANSWASTEOFMONEY]

I am doing a lq9 with a 4l80. I was going to throw away stock tranny and converter a 4l80 should bolt right up. The lines are different. I will tackle that when i get to it. I guess rear diff has a coolant line through the trans??? I was going to delete.

 

[Mogman]

I am doing a lq9 with a 4l80. I was going to throw away stock tranny and converter a 4l80 should bolt right up. The lines are different. I will tackle that when i get to it. I guess rear diff has a coolant line through the trans??? I was going to delete.

You do not need the coolers, diff or transfer case unless you plan on going under extremely heavy load in low range in something like sand for a long period of time.
Yes just about any 4WD 4l80 should bolt up, I was not aware of any cooler line differences, if your original trans is good, I would go ahead and use it as they are built heavy duty.

 

[EVANSWASTEOFMONEY]

You do not need the coolers, diff or transfer case unless you plan on going under extremely heavy load in low range in something like sand for a long period of time.
Yes just about any 4WD 4l80 should bolt up, I was not aware of any cooler line differences, if your original trans is good, I would go ahead and use it as they are built heavy duty.

I plan on deleting all of it. Just complications and leaks. I am just driving around town and light offroad.

 

[sail78385]

I am doing a lq9 with a 4l80. I was going to throw away stock tranny and converter a 4l80 should bolt right up. The lines are different. I will tackle that when i get to it. I guess rear diff has a coolant line through the trans??? I was going to delete.

Would love to see progress photos!

 

[TOBASH]

HummerH1 deleted all the xfer case cooling and he has almost 300,000 miles.

He also has M998 so no diff cooling.

 

[EVANSWASTEOFMONEY]

Would love to see progress photos!

STARTING A NEW BUILD WASTE OF TIME EFFORT AND MONEY

I WON A BID ON THIS LAST MONTH waiting for my EUC to come through. the plan is so repower it with a LSX and i have this silverado ss that has been beat to death over the last 20 years i owned it.

www.steelsoldiers.com

i started a thread. I have everything but the truck. EUC massive delays for me april till current waiting.

 

[sail78385]

STARTING A NEW BUILD WASTE OF TIME EFFORT AND MONEY

I WON A BID ON THIS LAST MONTH waiting for my EUC to come through. the plan is so repower it with a LSX and i have this silverado ss that has been beat to death over the last 20 years i owned it.

www.steelsoldiers.com

i started a thread. I have everything but the truck. EUC massive delays for me april till current waiting.

nice! I won my truck a few weeks ago, engine I’m assuming is toast so just trying to figure out the best course of action. I’ve really been considering 6.6 and 6L90, but idk. Might be easier to just put a LQ9 / LQ4 in it and move on….