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Wish List: 6L80E Swap for my 4L70E

MR.H

New Member
Joined
Jul 27, 2007
Messages
4
I recently had my Avy at the dealer for the Heated washer fluid campaign. While waiting for the tech to just pull a fuse, I test drove an 09 Avalanche with a 5.3 and the 6L80E with the tap "up" and "down" buttons on the shifter. All I can say is I like it allot!! The trans shifts very smooth and the acceleration is very impressive and when you get on it....The truck takes off not all that noise from the engine and no acceleration for 4 seconds which is well documented with the 6.0 and 4:10 gears for those of us with that setup. Off the line the 5.3 and w/6l80e would easily jump out to a 2 1/2 truck lead on my 6.0 Avy with the 4:10s. I would think the the 6.0 setup would have been even quicker even with 3:08 or 3:42 gearing.

Okay... Enough, All I want to do is put that trans in my Avy. There's a tread on the Trailblazer SS boy's web about this very swap and there's all types of issues with putting that trans in that platform. Since this setup is now available on the 09 then there shouldn't be to much needed to make this work in our 07 and 08 Avy's . I want to do this to my Avy, because I can't justify trading in my "07" for a "09" just to get cooled seats and the 6L80E.
 
Was thinking the same thing if and when my trans goes, i want to install the six speed. looked up the price and its not too much more than the 4 speed.
 
Some information to consider for the swap.  The 6L80E has its TCM (trasnsmission control module) in the transmission, 4L70E vehicles have the TCM mounted piggy back with the ECM under the hood.  This would necessitate a harness to couple the under hood connector to the new 6L80E.  I'm sure there are companies working on this harness extension already.  The next issue would be making the ECM and TCM talk to each other with the original operating system,  this swap might necessitate a custum operating system to be flashed in.  I have also driven the 6L80E in the new trucks and really think it is a superior tranny.  No big gap between first and second like the 4L70,  the 6L80 just keeps banging gears keeping the motor in it's sweet spot.
 
I would do it when taxes come.. My transmission is likely in need of changing out soon. Slips a little occasionally but I haven't done anything to it yet. Would love to put the 6 speed in its place if possible. Should expect a 2-5 mpg rise putting that sucker in there. Would likely pay for its self in less than 2 years with normal driving. Less with highway driving and/or towing.

 
You guys should really check out www.tbmsport.com - True Blue Motorsports for a 6L80e conversion kit. 
 
That would be good for the 07-08s. The price for a 6l80e may be over the top.
 
Contact Jesse at True Blue Motorsports - he has much, much more capability than what is simply listed.  As long as you are committed and not simply 'kicking tires' then he will spend the time and make it work for you.  He is an expert at adapting 6L80/90's to GM vehicles. 
 
So this transmission is significantly stronger than the 4L60E in these trucks?

I have a blown transmission in a car I have as well. I had a rebuilt transmission put in it and that lasted a whole 13,000 miles before it toasted. Luckily the warranty was for 12,000 miles...  :rolleyes:

It still needs extensive body work but this certainly would be an option to replace its currently blown transmission. Especially since the 5.3 Truck engines are more powerful than the stock Caprice LT1 5.7. (I am considering putting a blower on this 5.7 so having a strong Transmission is important and I am hoping not to have to go to the energy stealing 4L80E)

That car has an LT1 and ODB1 but I know the PCM can have the transmission contols turned off.

Is the housing on this 6 speed significantly bigger than the 4 speed? I know the 4L80E is bigger and needs some "massaging" of the transmission tunnel to work.


Rodney
 
Well since we  :jacked: AtomicVettes thread maybe post your ideas here.
 
Got it hahaha.

I just dont know, I wanna stay with the 6 speed. It seems like going down to a 4 speed would just be a step back. And again with the either ability or lack there of being able to get a 4 speed and just plug and play for computers and all that
 
The top gear seems a little too high to me, crack the window at highway speeds and it drops down the 5th gear.
 
MS03 2500 said:
The top gear seems a little too high to me, crack the window at highway speeds and it drops down the 5th gear.

Now, I haven't driven one with the 6 speed yet. But if you have more power, it would help stay locked into 6th gear instead of always shifting out.
 
My other truck has more power, still does the same thing.
 
Okay quick question for everybody, I know the 5.3 peak power numbers are over 3000 rpms, including torque. If I lowered my gears and put a higher stall converter in there would I be able to bring that peak power curve down lower in the RPMs? Is there a way I can modify my engine to bring the peak torque number lower down? It just seems like the 5.3s are more of a race car motor than a truck motor. Its one hell of a truck motor dont get me wrong, but with the peak numbers... just seems like it would be more fit in a car
 
You could probably find a cam that would bring the peak power and torque points down.  Wouldn't make much sense with a higher stall torque converter though.  Your peak hp would go down as it is a function of rpm x torque.  Trouble is that 325 cubic inches normally aspirated isn't that much for moving 6000 pounds around unless it's got some top end to lean on when you need it.
 
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