2011 sierra 1500 4.8 sl. Looking for the best option on transmission swap.

Stilljustsayian · November 2

Hey everyone,

looking to get a new/used/rebuilt trans for my truck.

2011 gmc sierra 4.8 sl crew cab.

ive been teetering with the idea of 10 speed. I’m not sure what year would fit (if any) or just keep the 4l60e in. Anyone have any thoughts?!

also, noticing 2007 and up will fit? If anyone has any more knowledge, I would appreciate it!

CamGTP · November 2

I will say this right off the bat. It will be impossible to put a 10 speed or even an 8 speed into that truck without basically doing everything over from scratch. Like doing a full engine and wiring swap with a GEN 5 engine and computer/wiring and then you have the fuel system and all that other jazz. So basically scrap that idea.

Going to a 6 speed is possible as that generation of truck did come with a 6L80e but it's still rather involved with wiring changes and computer tuning. Also likely that the driveshaft length would be different on the that transmission compared to a 4L60e.

Keeping the 4L60e is honestly the best approach with this. You need a 2009+ transmission for it to swap in so the wiring harness as the same number of pins.

newdude · November 3

Just do a built 4L60. One that has some stronger parts in it and maybe some 4L70 internals like the higher count planetary gear, etc.

If you want to keep it easy and gain a warranty on it, get a GM reman. 3 year/100k mile warranty that can be serviced at any GM dealer so long as its registered and you have your warranty paperwork.

Stilljustsayian · November 3

17 hours ago, CamGTP said:

I will say this right off the bat. It will be impossible to put a 10 speed or even an 8 speed into that truck without basically doing everything over from scratch. Like doing a full engine and wiring swap with a GEN 5 engine and computer/wiring and then you have the fuel system and all that other jazz. So basically scrap that idea.

Going to a 6 speed is possible as that generation of truck did come with a 6L80e but it's still rather involved with wiring changes and computer tuning. Also likely that the driveshaft length would be different on the that transmission compared to a 4L60e.

Keeping the 4L60e is honestly the best approach with this. You need a 2009+ transmission for it to swap in so the wiring harness as the same number of pins.

That’s great info, appreciate it!

Stilljustsayian · November 3

15 hours ago, newdude said:

Just do a built 4L60. One that has some stronger parts in it and maybe some 4L70 internals like the higher count planetary gear, etc.

If you want to keep it easy and gain a warranty on it, get a GM reman. 3 year/100k mile warranty that can be serviced at any GM dealer so long as its registered and you have your warranty paperwork.

I was looking at that option. I’m not confident in my transmission skills or I would rebuild. Those at the close dealerships about about $2500. So might be worth the hassle.

appreciate it!