Hello you all,

I have a 2005 GMC Sierra 2500HD SLT Crewcab shortbed 4X2 with the 6.0 Liter and 4L80 transmission and 4.1 gears. I would love to swap in a 6L90 transmission, what parts would I need to make everything work like it should?

Any help would be greatly appreciated!

PS. I had a 2003 model just like this with the 6.6 diesel and 3.73 gears, however, I prefer the gas engine (I do no towing whatsoever)...

 

The parts don't exist yet. There is no way to control the electronics of the 6l90e/80e.

 

One way would be to add a new ECM and wiring harness from a 2007.5 HD2500 as they cam with the 6.0 and 6L90e. Not sure how that would affect your gauges though.

Or you could check with Mast Motorsports I think they make a stand alone controller for the 6L80-90 series. And didn't SpearTech have a pickup running a 6L80 with there wiring harness and program a couple of years ago.

 

Speartech was working on a stand alone pcm, but I don't think they ever got all the bugs worked out.

 

I would take a 4l80e over the 6l80 series transmissions any day. Just my 2 cents. Vince B

 

I'd possibly look to MAST also (along w/. Speartech) since they seem to have already embraced some of the latest tech, i.e. VVT cams. Ya, Speartech had a project truck. I forgot what motor, but IIRC, they had to use electronics from both original truck & the CAN or BUS( whichever 1 of the 2 is the right name). Piggybacked. I wouldn't say it's easy, but w/. enuff work & the right people, I think it's doable. The 4L80E has already proven itself & has the aftermkt. support. The 6LxxE can't say that, yet.

 

I to want do this swap on my 8.1L

I gave up looking a few years ago but i noticed last month that TCI is advertising a 6L90E with computer harness for hot rods... You might be able to go that rought.

Looks like the trans and computer about $6K.... e mail and see what they say then post the info

http://www.tciauto.com/products/6x/

 

Then do it.
I don't recall TCI callin it a 6L90E, they just call it a 6X.

I remember when I saw TCI came to the market w/. the 6X. I was so excited, til I saw the price. Even the tranny alone is alot of $$$. So the hunt continues.

 

From a strength standpoint I'd agree. You guys need to get up to speed on the new tranny's though. The 4L60 series is near dead from a manufacturing standpoint.

 

Who needs to get up to speed?

4L60E has so many out there. It's weaknesses have been attempted to be rectified by the aftermkt. Problem is tho, no one has a retrofit for older stuff. At least not w/o. spending a shitload. The 80E is strong & doesn't use new style ( CAN or BUS) electronics, & therefore is more easily adapted to the weak 60e.
I wish GMPP or a whole lot of others bring a solution to poppin a 6 spd auto into older trucks. And make it reasonable too.