: 4L80E In A CTS-V...Fit's Better Than You'd Think

06-19-13, 09:50 PM
For those of you that didn't see this on the other forum-

Going back and forth about the trans in my CTS-V since the 3/4 syncro decides to come apart and engage 4th gear while cruising in 6th...best lead so far is the Rockland Standard unit with TR6060 internals for $3500 to my door.

Forgot about test fitting the 4L80 until I tripped over the damn thing. Long story short, it actually fits better than I ever imagined it would. No idea why GM didn't do this from the factory...other than they didn't put it in any passenger vehicles.

What will be needed:
- Headers must be modified/straightened since they turn into the trans. Not too bad and any fab shop should be able to take care of this.
- The passenger side lower firewall must be massaged for clearance. A heavy hammer should take care of this.
- The electrical connector must either be replaced with something different or the floor has to be cut and boxed.
- There is plenty of clearance in the bellhousing area (save for the bottom of the passenger side firewall area)
- A standalone controller is required for an LS6. The 04/05 PCM does not have enough memory to control the 4L80E from what I have seen.
- The trans cooler lines have plenty of room.
- The OE trans crossmember can be reused with an extension bracket bolted/welded to the bottom. The 4L80 mount is about 2" further back.
- The driveshaft will have to be shortened about 1 1/2"
- Will have to get creative for a dipstick...most likely the "Lokar" universal piece or something similar.
- Source an Auto shifter from a regular CTS
- Mate the CTS shifter with a universal cable.

Here are a few pics....enjoy!

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1701_zpse01e2ced.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1701_zpse01e2ced.jpg.html)

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1703_zpsfe9287e6.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1703_zpsfe9287e6.jpg.html)

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1704_zpsf0504f78.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1704_zpsf0504f78.jpg.html)

This is where the electrical connector and trans cable bracket hit the divers side of the floor/body.

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1705_zps0bac900a.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1705_zps0bac900a.jpg.html)

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1706_zpsdef47021.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1706_zpsdef47021.jpg.html)

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1707_zps87c17465.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1707_zps87c17465.jpg.html)

This is where the bellhousing hits the bottom corner of the floor/firewall.

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1708_zps9b9fc7e7.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1708_zps9b9fc7e7.jpg.html)

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1709_zpsaa6e7211.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1709_zpsaa6e7211.jpg.html)

This is the top of the bellhousing at the top of the trans tunnel/firewall. This is where I thought most of the problems would be. Plenty of room.

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1710_zpsb819f2a2.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1710_zpsb819f2a2.jpg.html)

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1711_zps6eeb5207.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1711_zps6eeb5207.jpg.html)

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1713_zps7674d2f6.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1713_zps7674d2f6.jpg.html)

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1714_zpsc5a3fd66.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1714_zpsc5a3fd66.jpg.html)

Another pic of the elect connector and cable bracket which is what kept the trans from going up higher.

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1715_zps72b388eb.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1715_zps72b388eb.jpg.html)

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1716_zps4a6f8d73.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1716_zps4a6f8d73.jpg.html)

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1717_zps94160cd0.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1717_zps94160cd0.jpg.html)

06-19-13, 10:32 PM
A few more pics...after looking at them it didn't look as if there was as much room as I was saying. Here are a few more pics I took before I pulled it back out.

Here is the lower passenger floor/firewall I was talking about. Just barely hits, but it does.

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1719_zpsf55e9f4a.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1719_zpsf55e9f4a.jpg.html)

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1718_zps4e63b1a7.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1718_zps4e63b1a7.jpg.html)

A shot of the dipstick

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1726_zps167f296f.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1726_zps167f296f.jpg.html)

A shot of the trans cooler bung...plenty of room..didn't look like it in the other pics

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1728_zpsd3f4fc34.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1728_zpsd3f4fc34.jpg.html)

Since I could not get it all the way in the tunnel due to the electrical plug and cable bracket hitting the floor/trans tunnel, I got a tape to show how much room is above and on each side since it was a little hard to tell in the other pics:

Driver side from edge of trans tunnel to trans housing:

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1722_zps3caee41e.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1722_zps3caee41e.jpg.html)

Passenger side from edge of trans tunnel to trans housing (you can see how much room the second trans cooler bung has in this pic):

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1724_zps054bba14.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1724_zps054bba14.jpg.html)

Top of trans to top of trans tunnel

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1721_zpsde55f1f8.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1721_zpsde55f1f8.jpg.html)

Proof I'm not bull-shitting everyone LOL

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1730_zps4d87a4c7.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1730_zps4d87a4c7.jpg.html)

http://i1336.photobucket.com/albums/o642/DMM416/IMG_1729_zpse9f05838.jpg (http://s1336.photobucket.com/user/DMM416/media/IMG_1729_zpse9f05838.jpg.html)

06-20-13, 07:18 AM
So, are you going to proceed with this project and actually do the mods necessary to install the trans?

GREAT pics, btw!

EDIT: Just read your other thread on ls1tech. Guess the fat lady ain't sung yet.

06-20-13, 09:34 AM
Good info. Interested to see how it turns out later.

06-20-13, 12:21 PM
Please keep a log as you move on this, I'm also interested. My T-56 is getting very close to a rebuild.... My 6.0/4L80e (Megasquirt'd and turbo'd) truck is just about rolling. I'd lean towards running the engine & trans with a Megasquirt over going with a factory ECU, but that turns in to a pretty big compromise when it comes to operator information/gages/etc... Would love to see how this goes down if you move forward.

06-21-13, 10:01 AM
Just a quick update. It appears we're using the 12589462 ECM, which was also used in several trucks/blazers/avalanches. I don't know how big of a deal it would be do tweak the ECU to deal with a 4L80e, anyone have any experience?

maggied 2005

06-21-13, 11:51 AM
Yeah...opened the tune last night and everything is in there to control the trans...with 4L80E in the drop down. Don't even know if a segment swap would be needed. I know we have a funky OS but do not know its true limitations. I'll send an email to HPTuners support and ask them about a segment swap. That would be awesome!

06-21-13, 02:10 PM
Controlling/ECU interface is really the main tricky part, the rest is mostly ordering parts and tinkering them in to place. Adding a bit to the wiring harness, making a crossmember, and ordering a driveshaft....

06-21-13, 04:56 PM
HEARD OF IT? :p :duck:


07-24-13, 08:17 PM
I would love to have a 4l80 in my V. Maybe after I finish my supercharger and 8.8 swap I will try this.

11-17-13, 11:51 PM
what ever happened with this? im in the midst of going with a t56 mag or 4l80e. id love to see some good pictures of the interferacne with the headers, (LTs if possible )

11-18-13, 09:21 AM
Sorry man, I wasn't doing the swap, I had the 4L80 on the floor in my shop and threw it on a Trans jack for all to see since this has been brought up so many times. I ended up with a Rockland T56 Magnum.

In all honesty, I think the swap will cost less than $1k as it pretty much bolts up only making contact at 2 points. The headers turn in towards the center, which is why getting the bell housing off is a PITA with them on. The collectors need to have the outboard pipes cut, then the collectors can be heated and bent straight with the outboard pipes welded back up. Not easy, but not hard for a good fab guy. I you need anymore pics, let me know.

Could not get any pics with the headers on with the 4L80 b/c the Trans occupies the same space as the collectors. You can't even bolt them up.

11-18-13, 07:49 PM
my turbo kit is built around the LTs i have always had. if i have to cut them up alittle to make them fit that would be fine. but it would be good to know if there is no hope for them sooner then later.
id be fine if i had to go back to stock manifolds if i still had mine. any info on if the exhaust system will fit around the tranny with out being cut up?


11-18-13, 09:30 PM
Straightening the collectors would change the intermediate pipe slightly. It would probably look like the GTO exhaust until about where the Trans crossmember is, then it could go back to the regular V1 exhaust. Again, not much for a competent exhaust guy, I would think. Actually, if the Pacesetter headers bolt directly to the factory exhaust, they may work. I'd have to see a pic of them installed from the rear looking to the front of the car. All I've found are side shots.

The hardest part you'll probably have is controlling it, but IIRC you're pretty good with HP Tuners so it would be more just pinning the extra wires.

11-18-13, 09:53 PM
I can hear the V guys already "it's an automatic ?", LOL as the rest of the world says "its a stick ?"

11-18-13, 11:00 PM
im working on hpt right now, i think i can get it to work bu if not ill go with a PCS-2000 standalone tcm.
this is happening...
thanks for the info.
what year was this test tranny?

11-19-13, 04:36 PM
Please keep good notes :) Shifter, converter, crossmember, driveshaft shortening, cooling, exhaust re-route, some minor body mods.... For someone handy with a welder and a checkbook, most of those aren't a big deal.

I'll be in too, once we figure out the trick to tuning it.

Maggied 2005V

11-19-13, 05:16 PM
The test unit was from 2000 Silverado 2500 2wd. It was a split bell housing like the pre-LS motors. The earlier ones will look the same but have different Trans cooler line location. The later 4L80 will have a full bell housing, but everything else should be the same save for maybe the elec connector location.