What transmission setup would work best for me? I have a 2003 Denali with a Whipple running at 12psi. I use the truck to tow about a 5000lbs boat. So far I have blown up three 4L65E built transmissions, whats my next step do I need to swap to a 4L80? I want a built proof setup so I dont have to worry about it all. I also like to drive the truck fast when not towing so I need something that can take the abuse. Any recommendations?

 

A FLT 4L80e Lv 5 and don't look back.

 

^^ I'm with stupid. Or you could do a level 4 4l80e from them. It has held up to lots of abuse over the past year or so

 

What all is need to convert from my 4L65 to the 4L80? Is there anywhere that sell a conversion kit?

 

Ive never seen what the under side of a Denali looks like but the 80E swap i did in my truck was a peice of cake.

Denalis are AWD right?

 

Yeah they're AWD.

 

I guess it depends on the Transfer case then?

Theres a gear swap or output/input shaft swap you have to do.

But other than that, everything else is easy.
You will have to fab up a Crossmember which only needs to be moved 6" to the rear.

https://www.performancetrucks.net/fo...d.php?t=413157

 

Don't forget about the drive shafts. In the 4wd 4l80 apps, they are 2 inches longer then the 60's so the rear shaft need to be shortened, and the front shaft need to be remade 2 inches longer.

 

Is there any shops that sell the conversion kits or do I need to gatther all the parts myself?