6BT cummins (24 valve) swap

Has anyone done the 6BT cummins (24 valve) swap and used the same 4L80E tranny? I have an 1151 with a turbo and I am not happy with the power. I also have a free cummins motor. Any help would be appreciated.

Moved to appropriate forum.

Mogman said:

Moved to appropriate forum.

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Lol...right after I put the post in, I tried to put it in the right place and couldn't figure it out. Thanx brother!

I have cruised a few Cummins sites and it looks like an expensive adapter. the common wisdom is without allot of upgrades the 24V will tear up the 4L80 because of the massive torque.
https://www.crossmembers.com/products/1989-2002-cummins-chevy-adapter-kit

Interestingly enough there were some van or bus applications that used the 6BT and a 4L80, that adapter angled the engine for clearance, I wonder if that would be useful in a HMMWV conversion????
I have no idea what mods were done to the engine as far as oil pan/pump pickup that may have been necessary
It looks like the 47RH is the preferred trans for many swaps, no computer and it can handle the 6BT power.
What is behind the 24V now??

Funny...I just read what your taking about. I also read that you can't go over 400hp on the 4L80...we will still be under 300 I believe...even with the added turbo. Will keep you posted. Thanx for all your help brother!

It isn’t the horse power that kills the automatics. It is the relentless torque and compression stroke power surges. Even the NV4500 manual had to go through several upgrades to handle the 6BT over the years. It never did get “bullet proof.” I suggest that whatever transmission you end up going with. Get 2. Don’t build the second unit until you figure out what fails on the first unit. Maybe by your 4th or 5th generation of improvements you will have THE 6BT automatic set up.

Kind of like Jericho Transmissions:

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Thank you! This is new deal for me, so all the info we can get helps. Just finding motor mounts has been an issue. Pretty expensive.

According to specs, the ISB 5.9 24v cummins puts out varied torque numbers, I would highly recommend looking up the specifics of the engine that you have. The 4L80E is rated at 440ft-lb of input torque. The stock 6bt is about that, but the ISB 5.9 puts out considerably more torque on some of those engines. The torque varies on the ISB from 420-610 ft-lbs. Here is a link that has torque ratings for different years ISB 5.9 from Dodge donor:

If you want to use the 4L80E, here is something I found on some aftermarket modifications that may have some value if you want to use that transmission:

Barrman said:

It isn’t the horse power that kills the automatics. It is the relentless torque and compression stroke power surges. Even the NV4500 manual had to go through several upgrades to handle the 6BT over the years. It never did get “bullet proof.” I suggest that whatever transmission you end up going with. Get 2. Don’t build the second unit until you figure out what fails on the first unit. Maybe by your 4th or 5th generation of improvements you will have THE 6BT automatic set up.

Kind of like Jericho Transmissions:

https://www.jericoperformance.com/about.html#:~:text=One%20of%20the%20best%20is,time%20for%20a%20factory%20team

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G56...

Dang I did not realize the 6BT weighed 320lb more than the Dmax... it is however all cast iron which does have its advantages.
The Dmax only weighs about 80lb more than the 6.5T, adding 400lb will be noticed.

Use a 4BT if you want less weight

TOBASH said:

Use a 4BT if you want less weight

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The 4BT is what these things should have had OEM. Similar power, 10 times the life expectancy, and it'd fit better.