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6L80E Performance build

Vindicta_Mihi

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Vindicta_Mihi Enthusiast

Vindicta_Mihi

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Just wanted to post on here, as I have seen no less than a thousand posts with questions about the 6L80E, specifically about the power threshold of a stock unit. I have a 2014 GMC Sierra SLT Crew Cab Standard Bed stock 3.42 gears stock drive shaft stock 20" rims/tires 6.2L fully forged top/bottom end "Armageddon Twin Nagasaki's" (GT3582R's) e-boost 2 gauge Z06/LT4 fuel system 365lph in-tank Armageddon fuel pump QTP exhaust cut-outs and laid down 965rwhp/850 rwtq on a mustang dyno with 18psi on 116 race fuel (cut-outs open). I say all of this because the stock transmission detonated the 4-5-6 shaft (intermediate hub) near the splines. I took it to a "race shop" that said they would upgrade as much as they could; and was told at the time, there were limited aftermarket parts available for the 6L80E. This was mid 2018 with less than 10K miles on the truck and about 500 miles on the engine/turbo build and I discovered that was not entirely true. I drove the truck after their work,  with "spirited road driving" while the roads were wet no less. Long story short; they f'd me and I detonated the 4-5-6 stock intermediate shaft again within 100 miles and no traction at all. They apparently replaced all parts that were broken with stock parts! Moving on, I took my truck to a different shop and researched my a** off and found PATC Transmissions. I had a warm and fuzzy after speaking with them and ordered the Phoenix Level 4 Master Rebuild kit among a few other minor accoutrements and re-tuning of my TCM by Mike from Century Automotive. It is now APR 2019 and I am about 1 1/2 weeks away from having the my billet planetary gear mailed to me; for the new, more reputable shop in my area to install all of this PATC bada**ery. If anyone is truly interested, I will post new info once I put the new Phoenix Master Rebuild kit through the ringer with the full weight/horsepower/torque of my particular application...I hope this helps if there are some lost souls out there that may be headed down the same long. hard. road. of a "full send" like myself! Please post if you have questions/comments/concerns; as I have "been there done that and forgot the t-shirt" with the L86/6L80E so far. 

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truckguy82 Senior Enthusiast

truckguy82

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You doing awd launches?

 

curious what you need to do to the transfer case at those power levels.

 

All I’ve learned about thr 6l80 leads meto believe you will be hard pressed to get any builder to ever have it handle a ton of power long term.

 

As I’m sure you already thought about this, shame you didn’t dump all that money into a 2015+ with the 8l90. Now you have a ridiculously awesome truck that could potentially never reach its potential without a 4l80 swap.

Mike GMC Enthusiast

Mike GMC

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I thought I read something recently about the next 3/4 ton with the 6.6 gas engine.  They talked about an upgraded 6 speed.  I think it was based on the 6L80, but I could be wrong.  Maybe the next step would be the trans from the diesel engine 3/4 or 1 ton truck.  They come stock with 900+ ft-lbs of torque.  It might be a match for your setup.

 

wforrest08 Senior Enthusiast

wforrest08

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I’m more impressed that you didn’t manage to tear the stock driveshaft in half yet and somebody ran that set up on their dyno with it! 

1SLOW1500 Senior Enthusiast

1SLOW1500

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6l90 is good in the 800rwhp. Where are parts out for both but it seems they aren't well known or main stream.

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Vindicta_Mihi Enthusiast

Vindicta_Mihi

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truckguy82- No awd launches for me, its a 2wd.

wforrest08- I cant believe the stock drive shaft and the rear diff hasn't given out yet either! I dont take it to the track, its just a cool daily driver to take to a show here and there and talk to people about car stuff.

Mike GMC- I was originally going to put a 4L80 in it, as I heard they can be built pretty solid, and at the time $6k or $7k sounded a lot better than about $12 for the 4L80. If I grenade this one with the PATC kit...thats probably where I'm headed next.

1SLOW1500- I was also going to replace it with a 6L90 core but couldnt find one and up here in Alaska shipping would have been a little pricey too.

1SLOW1500 Senior Enthusiast

1SLOW1500

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I swear some times I think these threads are a curse. Blew my trans. Oiled down the road twice.

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1SLOW1500 Senior Enthusiast

1SLOW1500

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So I will be getting a new trans for free but started to think ahead. I want the new converter installed for sure and may as well order the stage 3 trans. Retail is $4500 I will can and see what my cost is.

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Vindicta_Mihi Enthusiast

Vindicta_Mihi

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1SLOW1500- That sucks man! If you need a converter, I actually have a TCI 2800 stall that I purchased the first time I had the trans "rebuilt". It only has about 100 miles on it and it is the bolt together option, not welded. Let me know if you are interested, as you could at least look inside of it and upgrade/change some internals in it if you wanted to. 

1SLOW1500 Senior Enthusiast

1SLOW1500

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Posted
31 minutes ago, Vindicta_Mihi said:

1SLOW1500- That sucks man! If you need a converter, I actually have a TCI 2800 stall that I purchased the first time I had the trans "rebuilt". It only has about 100 miles on it and it is the bolt together option, not welded. Let me know if you are interested, as you could at least look inside of it and upgrade/change some internals in it if you wanted to. 

I may need that. What size is it and single or dual. Have part number. Just PM me.

Vindicta_Mihi Enthusiast

Vindicta_Mihi

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**Update**

Currently just waiting on the billet planet from PATC to be shipped to me, and this may not be news to some of you, but my trans builder is going to use a new factory 6L90 "hub" inside my 6L80; which is supposed to be stronger and accept 1 more superglide clutch which comes in the PATC phoenix kit. 

This is the photo of the grenaded 4-5-6 intermediate shaft. (The 6L90 "hub" pictured in the rear, left side of the photo).

20190327_100506.jpg

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