Will 6L80e fit in an FJ40 without major sheet metal mods

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Apr 12, 2012
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background: i have a 1972 FJ40 with 4 BT and 700R4. Planning to install a R2.8 and would like to use a 6L80e with atlas 2spd. I could use a 4L60e but prefer to change the bellhousing instaed of using an interim adapter.
I am not concerned with length since it is essentially the same as the 700R4

What I dont know is comparative diameter to the 700R4 and will it clear the tunnel without major sheetmetal mods
Anybody with experience in the tranny swap
 

matzell

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background: i have a 1972 FJ40 with 4 BT and 700R4. Planning to install a R2.8 and would like to use a 6L80e with atlas 2spd. I could use a 4L60e but prefer to change the bellhousing instaed of using an interim adapter.
I am not concerned with length since it is essentially the same as the 700R4

What I dont know is comparative diameter to the 700R4 and will it clear the tunnel without major sheetmetal mods
Anybody with experience in the tranny swap

It is huge! I have one in my race car behind a 6.2L. It is a lot taller than a 700r4. about 100lbs heavier too. If you do it, talk with Zero Gravity performance out of AZ. He can set you up with tunes and tap shift.
 

Mieser

 
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Mar 23, 2004
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The 6L80 isn't much taller from centerline to the top, but wholy cow is it a lot deeper from the centerline to the bottom. It is about like an old granny 4 speed manual transmission with a big old belly....
 
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The 6L80 isn't much taller from centerline to the top, but wholy cow is it a lot deeper from the centerline to the bottom. It is about like an old granny 4 speed manual transmission with a big old belly....
:rofl:

Thanks for that. I now have this image of my LC looking like a pot belly pig :( I will get that measurement today. My 700r4 pan is about 2” below the frame rail currently.
 
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Measurements:
6L80e centerline to botton of pan 9 1/2”
700R4 centerline to bottom of pan 7 1/2”
I can change the pan on the 6L80 and gain an inch to 8 1/2”
Might be able to push it up an gain an inch but without the R2.8 its a maybe
The 6 speed 6L80 with 5-6 being a double overdrive will allow lower gear ration and still maintain crusie rpm
Will make the final decision when the engine gets here
 
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Why not the dodge 8 speed that Axis is supporting?
No thanks
Limited transfer case adapters, Reliability issues, cost, after sale support immediately come to mind.
I would drop in a 4L65 or 4L70 before that ever happens, also current transfer case is now a split case instead of atlas.
Thanks
 

Mieser

 
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Mar 23, 2004
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702
No thanks
Limited transfer case adapters, Reliability issues, cost, after sale support immediately come to mind.
I would drop in a 4L65 or 4L70 before that ever happens, also current transfer case is now a split case instead of atlas.
Thanks
Just throwing it out there. Axis seems to have it pretty nailed down with a lot of support.
The 6L80 isn't that well supported in the market really either?
 

Gotta be Geared

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I have the 6l80 in my personal 40 and it fits well. I had to notch out the under seat gas tank area because I clocked the np205 up a bit. I really enjoy the 6l80, the low first is great and the support for tuning is continually growing.
 

Mieser

 
Joined
Mar 23, 2004
Messages
702
If you are going to go to all the trouble of a big engine and trans swap, why not just rebuild the tunnel and make the belly flat?



 
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6C1B87C9-FFA2-4D2F-8135-3048BC9730A4.jpeg

The thought of tearing up and redoing
is more the i am willing to do. I will live with
a coiple inches below frame rails and a new skid plate
 
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