Try to find an 01 or newer 4x4 4l80 for an easier swap. It'll hold the 600hp without a problem. You can contact Justin at EAD through this forum. He will sell you the gear for the transfer case and can help with other items you might need. Also, with 4.11's you are already ahead of the game. I would think that you had too much gear with the 65e and a turbo as long as you don't run crazy tall tires.

 

I actually don't have 4.11's now but I would have the gearbox changed in the 80e to reflect it in the final ratio. Switching the gearing in the front and rear of the escalade costs about as much as a fully built 80e! I would leave the top two gears standard for cruising mileage. I am probably leaning towards an STS kit, just because it will allow me to grow in HP easier as my cravings grow I will have 24" wheels, but the tires will be low profile. Is it still worth it to get the 4.11 ratios done in the tranny for low end grunt?

valsperformance....I love all the help you're giving me here (in a heterosexual kind of way of course)

 

I have aquired the STS turbo kit, and am ready to move forward with the tranny. I looked into this, and I'll have to spend about $1100 more just to get the 4.11 gearing in the tranny. For a T76 turbo on a 408, is this really necessary?

Thanks

 

I don't think it's necessary to do a gear swap. Look into a higher stalling converter instead. The 1-2 2.75/1.75 tranny gear swap might be a good idea, but I wouldn't bother with changing your diff gears.

 

Please elaborate on that gear swap you are referring to.

 

Standard 1st gear on the 4L80E is 2.48, standard 2nd gear is 1.48. The 4L80E's that came in the RV's had a 2.75 1st and a 1.75 2nd gear. You can swap those gear sets in, I think the kits were about $500. Something to consider.

You may be fine with the stock gearset though, and just get a higher stalling converter. That's probably the best overall way to go.

 

Maybe I should just jump into the RV tranny...

I'm buying one used from a junkyard anyway to shave off costs. If it blows up, then I'll build it up.

 

I got my tranny from a junkyard. It had 26k on it when I bought it. I've put another 60k on it. Its bone stock and has held up to 600 rwhp for a couple of years flawlessly. I have 3.42 rear gear and it works great with the tranny and turbo. Also have a 2800 stall if that helps.

 

which one is a stronger t-case? i wanna do this in my tahoe. i have a bw 4482 unit in it, awd but i have a 4low option i would like to keep.

 

i recently had an opportunity to buy a 2006 4l80e 4wd trans for cheap and passed. if someone wants/needs one pm me and i'll see if the guy is still selling it. shipping would be a bitch though