2005 Silverado motor and trans swap

Bmheathcoat · February 23, 2020

Hey guys. So I’m very new to all this so if I ask a dumb question I’m sorry but I’m trying to learn here. Ok I’ve got an 05 Silverado that I’ve had for a few years now and I love it best truck I’ve ever owned. It’s getting up there is mileage and I’ve been setting aside money to eventually replace and upgrade the motor an tranny if I can. So I’ve researched different ideas over the last several months and have been left with more questions than answers. I think I want to upgrade from a 5.3L to a 6.0. What do I need to know about this and what is the best tranny to run with that motor? Can the differential even handle a larger tranny? Any info you can share would be much appreciated. And feel free to tell me different ideas as well.

riverbanks · February 23, 2020

4l60e will still work,the 6 is the vehicle weight,6k#,unless you want to beat it hard,then 4l80e,8k# truck

Brian715 · February 23, 2020

I would agree. Just get the 4l60 built a little stronger to handle the added torque and power. The 6.0l will bolt right in and plug in just need to get it tuned. You can use the trucks factory ECU.

Bmheathcoat · February 23, 2020

Will the 6.0 bolt up or will I need motor mount adaptors? And I’ve heard the 6.0 will eat transmissions pretty bad is that true?

CamGTP · February 23, 2020

It bolts right up. Use your 5.3 flex plate.

Put it this way, the 6.0 was installed with a 4L60e in the early escalades, the silverado SS trucks, gmc sierra VHO trucks and yukon denali's on that era. They all survived and if they had problems it would be the same problems you'd run into with a truck that had a 4.8 or 5.3.

Do a rebuild on the 4L60e and upgrade some of the internals if you wish, then you'd know for sure that it will handle the extra hp/tq of the larger engine.

Bmheathcoat · February 24, 2020

Cam gtp thank you I will look into that!

carkhz316 · February 24, 2020

On 2/22/2020 at 6:15 PM, riverbanks said:

4l60e will still work,the 6 is the vehicle weight,6k#,unless you want to beat it hard,then 4l80e,8k# truck

Just a slight pedantic correction, but the 60 and 80 are arbitrary torque capacity designations by GM, and nothing to do with vehicle weight. While the 4l60 and 4l80 are vastly different transmissions physically, this is what the numbering system is. This is the case with virtually all GM automatic transmissions.

carkhz316 · February 24, 2020

On 2/22/2020 at 9:20 PM, CamGTP said:

It bolts right up. Use your 5.3 flex plate.

Put it this way, the 6.0 was installed with a 4L60e in the early escalades, the silverado SS trucks, gmc sierra VHO trucks and yukon denali's on that era. They all survived and if they had problems it would be the same problems you'd run into with a truck that had a 4.8 or 5.3.

Do a rebuild on the 4L60e and upgrade some of the internals if you wish, then you'd know for sure that it will handle the extra hp/tq of the larger engine.

Most of those trucks (with the 6.0) got a slightly upgraded version, the 4l65 which really only added an additional 3/4 clutch friction, and 5 pinion input and reaction planetaries. The worst offender was the H2 got it, struggling to haul around 7k pounds empty. Some vehicles even got a 4l70 version, though I'm not certain of which vehicles as I've not seen one in the wild.