Vortec350ss

iTrader: (20)

I think I would too. Not to mention that a turbo loves the added load of the longer first gear available in the 80e, the 6 speeds have a very short 1st gear. Might not be the best for a turbo.

built408

iTrader: (10)

They aren't cheap to handle 1000 hp, but it can be done. 50% of the trans living is in the tuning.

brent1976

iTrader: (1)

I decided to keep the 4L80e, it's not worth the extra hassle and money. I ordered my wiring harness yesterday with the wiring for a 4L80e. Man are wiring harnesses expensive, by the way.

Boober

Speaking as someone who had a 6L80 built only to have it taken back out 3 weeks later because of solenoid issues, you made the right choice. Most builders won't touch the 6 speeds and the ones who actually will have run into many problems. FWIW, the stock trans will actually do pretty well up to about 600hp as long as you don't abuse it and most importantly keep the temps in check (my initial problem). They can be overly sensitive to aftermarket converters and if the converter doesn't like lockup, the temps will skyrocket. Time will tell if these transmissions can be built and engineered to be reliable at 1000+HP. For now, sticking with a successfully developed trans is the way to go for big power.

brent1976

iTrader: (1)

Boober, that's pretty much what my tuner told me too. I'm glad I didn't decide to say F everybody and do it anyways. I was thinking since my truck is only 3500# it wouldn't have a problem, but it seems to be torque related, not weight. That's why I like this forum the best. Thanks for the help guys.

Area47

the stock 6l80 trans can handle 800whp. if the tune is spot on. most people can't get it right and it nukes it.

Karlen

Curious to watch your build.

brent1976

iTrader: (1)

I can't wait to get started, but parts are holding me up. As soon as everything gets here I'll do a build thread. Hopefully I can remember to take pictures as I go.

bdubb

iTrader: (2)

I see you already went another route which I think is a better and cheaper option as well.

To answer the first post though for anyone checking this thread later, the 6L80 does have shifting issues once you up the power. At least in my case which was with a multi disc converter locking up in 3rd and 4th and a transmission tune back when I was running around 8-9 PSI from a whipple. The issue I experienced under WOT was that the shift points would be missed almost every time no matter what they were set to. It would always hit the rev limiter and then shift.

I have a fully built 6L80 from CircleD that will go into my truck next week but my engine is back close to stock power output these days so I won't really be testing it out much. I can say however that the stock transmission did show signs of wear and tear from the blower and me driving it hard, but to this day it still continues to work and gets me from A to B without major problems. I have learned to live with a few hiccups from it though, which should be gone with the built trans going in and having the converter ran through as well before everything is bolted back up.