LS7 427

I'm going to replace the 6L80E to a TH400 with a transbrake this winter and would like some help with what parts will be needed. My block is an LS7. Aside from the transmission, converter and driveshaft what parts/part numbers will I need. I'm also planning to use a B&M Pro Ratchet shifter, is that a good choice?
Secondly, what issues will I have to deal with regarding the TCM and whats necessary to remedy them?
Anybody willing to take the time and make an itemized list? All help would be appreciated. Thanks guys.

Bryan

motion427

iTrader: (1)

Some upgrade the 6L80 to a 6L90.

What about a 4L80 instead?
Then with the right harness,you can still use the factory ECM to control the 4L80.

You can check with Slowhawk. He did a T400 swap not too long ago actually as far as I know.

LS7 427

Thought lots about the 4L80 and TH400. In the end the 3 speed won out.

Bryan

THMotorsports

Ill always side with a 400. Im biased though, all my street cars have run a 400!

Raoul-Duke

iTrader: (6)

Have fun driving on the highway sucker!! lol jk

SLOW SEDAN

iTrader: (13)

If its anything like the G8 which is should be since they are both Zeta chassis vehicles its a fairly straight forward swap.

I was able to swap in a TH400 and Circle-D LS/TH400 converter. I used the existing crossmember with a Energy Suspension TH400 trans mount, it bolted right up. I already had a DriveShaftShop driveshaft that I was able to reuse by swapping the transmission end out for a slip yoke.

You need to jump the GMLAN wires on the TCM connector and use HPtuners to flash in a manual file. You will have to delete a few lost connection with TCM codes.

Highway cruising is about 400RPM's higher, I was at 2600RPM with 6L80 and 3.70 diff, with the TH400 I was at 3,000. Wasn't bad at all and I still got 19-20MPG but the nicer part was it dropped over .5 on the track.

I thought about a 4L80 but after dealing with the 6L80 I no longer wanted a computer controlling the trans.