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6.2L L92 Modification and Swap into 2008 Avalanche

The problem with trying to use the 6l80 is the controller, I haven't seen one successfully installed yet,
 
Randy said:
Sounds like a good plan..

I would love a 6L80, I wish they weren't so expen$ive and I don't think there's a simple coversion for mine, yet..

Think Allison Randy the 6 speed will never happen. Sorry for the :jacked:
 
Yea, that's what I've read out there. You can use the stand alone controller but you have to go into the ECM and remove most of the trans programing but not all of it. You have the speed sensors and transfer case programing that has to stay and probably allot more.. You could probably get one of the tuners to figure it all out if you wanted to be the Guinea pig..


Allison would be even tougher and $$ having to go with a body lift, new transfer case, crossmember, wiring harness, ECM shall I go on..
 
Yeah I don't want to Jack this thread but a 6 speed behind a 8.1 will not last and you can not add the 6 speed to a 08 down AV.
 
The TBSS and Silverado guys have already done the 4l60-80 to 6l80e swap so it wouldnt be hard to transfer that over to the ava platform. Its a PIA from what ive been reading and really not worth it as the slap shift is slow and its expensive to build with not much available. A built 80e would be cheaper and just as strong..plus if you want a 6spd TCI will make the 80e into a 6spd for ya.
 
TCI was the one I was looking at but like I said way to much.. $7,000 for a trans!!
 
That is the downside..but building any transmission isn't cheap. Heck my Built 4l60e in my AVA cost close to 5 grand.
 
jpsteele25 said:
That is the downside..but building any transmission isn't cheap. Heck my Built 4l60e in my AVA cost close to 5 grand.

I am thinking about getting a built trans by transmissioncenter.com getting the extreme duty 6l80e
 
09chevyavy said:
I am thinking about getting a built trans by transmissioncenter.com getting the extreme duty 6l80e

This:
Yeah I don't want to Jack this thread but a 6 speed behind a 8.1 will not last and you can not add the 6 speed to a 08 down AV.

A lot of guys with the 6L80Es are swapping them out for the more stout built 4L80Es. It seems even the built 6Ls just don't hold up to the power.

The only thing you would gain is a slight increase in mileage when locked up in OD. But even that is slight, at best.
 
Zef_66 said:
This:
A lot of guys with the 6L80Es are swapping them out for the more stout built 4L80Es. It seems even the built 6Ls just don't hold up to the power.

The only thing you would gain is a slight increase in mileage when locked up in OD. But even that is slight, at best.

But still, I like the 6 speed. And the ones that transmission center are producing, at a cost of about 7k can hold 1,100 hp... thats pretty stout I must say.

Here is the one I want for just over 5.5k

"This Extreme Duty 6L80E transmission comes with our Full Billet torque converter, that has a very large Red clutch. Full Billet means both the converter housing and the clutch apply piston are both billet. This converter is built in-house at PATC. The Alto Red Eagle Power Packs are here and we install them in our Extreme Duty 6L80E transmissions. The 3-5-R direct clutch has 14 single sided clutches and the 4-5-6 overdrive clutch has 18 single sided clutches. These are two weak points in the 6L80E transmission. This is a 75% larger clutch apply area in the 3-5-R clutch and a 50% larger clutch apply area in the 4-5-6 clutch. We use our exclusive PATC / Alto Kryptonite clutch lining on the other clutch sets. In our extensive testing with the 6L80E transmissions we have observed repeated shaft failure at the joint between two shafts and drums. TIG welding of this area eliminates this problem. Also included is our billet intermediate shaft and hub assembly. Developed as a stronger replacement for the problematic failure of the OEM shaft when high horsepower, superchargers and turbos are used. As an added bonus this transmission has an oversize filter. You can buy this Extreme Duty 6L80E transmission and Full Billet torque converter for $5690.00 plus a core charge on the transmission and converter. Custom tuning must be performed to the TCM to accommodate the new parts. Call Blake @ 1-888-2012066 for tuning and transmission details."
 
09chevyavy said:
But still, I like the 6 speed. And the ones that transmission center are producing, at a cost of about 7k can hold 1,100 hp... thats pretty stout I must say.

Here is the one I want for just over 5.5k

But a built 4L80E will hold the same power for less than half the cost.  (y)
 
Zef_66 said:
But a built 4L80E will hold the same power for less than half the cost.  (y)

But what about my gas mileage, and also wouldnt I need to get a lower gear ratio than just my 3.08s? They would stink with a 4 speed
 
09chevyavy said:
But what about my gas mileage, and also wouldnt I need to get a lower gear ratio than just my 3.08s? They would stink with a 4 speed

Are you interested in fuel mileage or making power to the pavement/dirt? With the mods and upgrades you have planned and the towing/off-roading you do, I figured you would be interested in getting power to the wheels and having it be reliable.

I mean, you've already lifted your truck and put on larger tires, both of which lower mileage. If you are interested in fuel mileage, then spending $5500 on a transmission that is going to save you maybe 1 mpg isn't very cost effective.
 
Zef_66 said:
Are you interested in fuel mileage or making power to the pavement/dirt? With the mods and upgrades you have planned and the towing/off-roading you do, I figured you would be interested in getting power to the wheels and having it be reliable.

I mean, you've already lifted your truck and put on larger tires, both of which lower mileage. If you are interested in fuel mileage, then spending $5500 on a transmission that is going to save you maybe 1 mpg isn't very cost effective.

No, MPG is not the highest thing one my priority list and I do want performance goals to be met and such. But with those two overdrive gears I am currently able to still get 17 on the highway and 12 in the city. Thats not too great hahaha. Im just saying it seems like having those gears not there would bring me down to about 7 and 12 ya know? Especially with my 3.08 rear gears right now
 
09chevyavy said:
No, MPG is not the highest thing one my priority list and I do want performance goals to be met and such. But with those two overdrive gears I am currently able to still get 17 on the highway and 12 in the city. Thats not too great hahaha. Im just saying it seems like having those gears not there would bring me down to about 7 and 12 ya know? Especially with my 3.08 rear gears right now

4L80E final drive (4th) ratio is .75:1
6L80E 5th ratio is .85:1
6L80E 6th ratio is .67:1

So not a huge difference from the 4L80E to the 6L80E. Without doing any math, less than 10%. So again, you wouldn't lose that much. Not enough to justify spending the extra $2500, IMO.

I mean, in my truck, I have the 8.1L and the 4L80E with 3.73 gears, all stock. I'm getting 11-12 while towing, and 14-15 on the hwy. These numbers are pulling mountains in PA. If you were to run the same tranny (4L80E) behind your 5.3 with 3.08 gears and get the mileage numbers you are thinking, you have something considerably screwed up.
 
True true, but you guys dont drive the way I do, I drive her hard. Yes, most of my driving now consists of decent city driving but most speeds of around 50-65 mph but from the start I like to get it rolling. And what about going backwards like that? I mean how would I control it and all that. Would it bolt up to my stock driveshaft, ECU would work seemlessly, all the computers, gauges everything would work the same?
 
Honestly for you i would stay with the 6 speed. However, i dont see the need to have one thats good for 1100 hp, unless you plan on big power adders.
 
WHAT HAPPENED TO PIX OF NEW, GO FAST LS3 PARTS...
AND THE PRETTY ASSISTANT ??
 

12jp6.jpg
 
LOL! 

Leaving for vacation tomorrow, so there won't be any update for at least 12 days.  Sorry guys!  I'll see if I can get a picture of the garage assistant in her natural habitat. haha.
 
Dang, so have to wait another 12 days?  :D

Well, I guess in the meantime we can continue the trans debate.

The 6 speed TCI is just a built 4L80E with different transmission ratios and valve body.  So could probably do it on your own (either 5 or 6 speeds), just not sure if it can be integrated into a stock ECU cal.

More information here (be sure to read the text in the photo galleries).

http://www.carcraft.com/techarticles/1306_performance_guide_to_the_gm_4l80e_transmission/photo_02.html
 
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