1000 whp is up there... I think id start with the 6L80 and see how it goes if it were my truck. There are shops who build race prepped versions now and its plug and play which is the most attractive part. Swapping trans with these newer ECM/TCM/BCM set ups is pain. VSS signals all different and there are tune related gremlins to get all the parts jiving properly. Doable, just a frustrating experience.

But budget and pain aside? 4L80 wins my vote

 

I was just wondering.. i have no experience with a T56
just seen a bunch of the stock ones acting up with alot of power. but i guess if you can get a built one and it will hold.. use it.

Why are the 4L80E's hard to swap in those trucks?
All ive ever swapped them in to is a older truck like mine.

 

Since the 6L80Es have there own TCM once the 4l80e goes in it'll act haywire so I would need a new wiring harness plus I would only be able to get 2nd gear and lots of BS and don't wanna spend 10K on a swap

 

I have not done a ton of research which is why I am asking but does no one offer a built 6l80/6l90 to handle what your looking to put down for power? What about Circle D I know they have 6l80 stuff. Again I have not researched it so i don't know the facts just wondering.

 

Circle D wants $15,000 for one thats limited @1200hp on a car and won't guarantee it, same with PATC stock ones are out lasting built one from my research but I wanna hold another year to see what they will offer down the road

 

Check with llavero a tellez he just did a 6l80 to 4l80 not too long ago

 

No ****? Thanks Might have to do that then

 

I don't know if you have checked century transmission but they are big with the corvette crowd. They were one of the first to start building high hp 6l80es.

 

Say waaah?

Circle D is finishing off a tune on my truck now with one of their fully built 6L80's. Only thing it doesn't have is their new planetary gears which they are still testing from what I understand. It was closer to $5,000 without the removal and install, not $15k.

For $15k I'd like to know what you get with it...well no not really. If I had that to burn on a transmission I'd just spend a little more and install an EMCO sequential along with buy a whole different vehicle to put it in and make use of a 15k plus transmission.

 

Instead of the T-56, folks should be looing to the TR6060 for a nice 6 speed in a GMT-900 truck. The MH3 variant has guts that are rated for for 650 lb/ft stock. The Camaro version M10 has the gearset which is rated for 430 lb/ft. Dp some swapping and building and you could have a very strong TR6060 in a Camaro case that could be used in the GMT900 truck.

For an auto, one could always skip the electronics and use a th400 trans and GC over/underdrive and come in under 1/2 of the huge numbers I'm hearing here. Run 4.88 gears if you wish and cruise down the highway at 2100rpm.

peace
Hog