blu00rdstr

I started out by contacting Chuck at FLT asking about the trans, and his initial email asked if I was going to hammer the truck since I asked about the 4L80E swap. There are some Avalanches running 4L80E transmissions with crossmember modifications and reprogramming.

I'm thinking this is a bigger question about the drivetrain, block material, use cases, etc.

The truck is a 2005 Avalanche 1500 Z71 4x4 with 5.3L.

The 2008 LS3 engine is from my bent C5 corvette, shortblock built by Bruce of PowrMax, forged crank and rods, Diamond pistons, D1SC, cam designed by Rick @ Synergy and tuned by Synergy up to 738rwtq, detuned to 660/650 due to high rpm belt slip, and I have a larger Innovators West pulley sitting in the garage to fix that. Dual feed fuel rails with 1/2 fuel lines, and dual fuel pumps.

F&R truck differentials were rebuilt at 20K and 30K due to needle bearing flaws. Are diffs a weak point? The trans is weak from all I've read.

The use case is daily driver, occasional towing, and benchmark it once or twice at the track.

Is an aluminum block wrong for a truck? What am I getting into here? My 'vette experiment cost $35K on top of the original cost of a 2yr old corvette. Am I better off just getting a diesel truck and forgetting the mod route?

PitchblackC3

iTrader: (3)

Nothing wrong with a LS3 in a truck, but your cam may not be the one you want. Definitely wouldn't use it with a 4L60e.

Avalanche2002

After the 4L60E the weak point is the 10 bolt and specifically the G80. Another fellow FI Av member I know has had to build his tranny twice. The first time the G80 blew, taking out the rear gears and the tranny. He installed a Detroit True-Trac the second time around. The second time he believes the diff locked up possibly due to a chipped tooth on the ring gear, which locked the driveshaft and took out the tranny again.

Even a built 4L65E won't live long on 600 hp in the Av if you ever hammer it at all, and what's the sense of having the power if you can't use it? The big issue with the Av is that it is a heavy 6000 lb pig and the 4L60/65E is just not made to stand up the the combination of power and weight.

dhpro

iTrader: (3)

Oh man...all I can say is buy mine and save urself the headaches!!!
Motor will be fine, rear end will be an ongoing issue, tranny MUST be upgraded to 4L80 as there is NO 4L60 no matter how built that will sustain a thrashing for long. Daily driver will be tricky unless u have the time to tinker with it constantly. It will be a constant cash drain, but then uv already gone down that road...Good Luck!

blu00rdstr

Thanks guys, good sound advice from guys who been there done that.

In 2002 I bought my 2000 Vette stock with P1SC for $40K. Put $35K into it. Now browsing cars.com I admire the kind of cars I could've bought for $75K. Don't want to make the same mistake with the truck.

I'm going to go shopping for a new diesel with low interest rate (or lease) and a 100k warranty. I think a lease is a good idea these days since it's so hard to resell anything and prices are dropping like lead stones.

Heads up, I think the economy is about to take another deeper dip. Be conservative.

dhpro

iTrader: (3)

NEVER add up the cost of mods! Fact is the cost of all the R&D is the real reason it ends up so high, but thats the price for a one-of-a-kind ride. To buy a new built hi-po package from an aftermarket builder like Henessey, LPE or others will cost u minimum $65k, so dont feel so bad!

dhpro

iTrader: (3)

BTW...I think you're dead wrong. Stop watching so much Oprah and CNBC!