Before everyone goes crazy on this post and says "Use the search bar!" I did use it and came up with nothing but manual t56 information and a few slugs of autos but nothing useful.

I am too old and beat up to be shifting, especially in a cruise or just traffic jams. So, as much as I would love to put the manual in, it is just not feasible.

I am planning an LS3 swap and want to get information from people that have swapped in an auto trans. I currently have the stock 5.7 and 700R4 combo. The 700R4 is a total piece of garbage and have had it out 3 times in the last 2 years to be redone. I even went with a constant pressure valve body to remove the necessity of the TV cable and it is still not working properly. So, this decision is very important to me. I would like to stick with a 4 speed for highway cruising to shows that are far out. Do not want my girl to be a trailer queen. The 4L60E is the one I find the most information about outside of these forums. Whatever automatic trans you have please, just give me your thoughts on whether you like it or wish you had done something else.

 

Well if you don't like the THM700-R4, then I would pass on the 4L60E.

I would recommend the 4L80E.

 

Well, since you posted in the engine swap section and not the transmission section, I bet you just searched in the wrong place.

700 and the 4L60(s) are all basically the same. You'll probably want a 4L80E or better with an LS3, but a TH400 will work too

 

As previously stated the 4l80e is a strong trans. Ive seen several builds using the 4l75E and the even bigger 6l80e. With the later you may need to modify the trans tunnel.

 

What are your power goals? If your 700r4 failed 3 times behind a stock motor something internally is set up wrong in there. If I were to do it again I would go with an 4l80 or 6l80 just for peace of mind.

 

I would very strongly recommend NOT using a GM 6L Family Transmission.

If you want a 6-Speed, go with the original ZF design: 6HP26 Transmission and use an adapter.
Or the Ford variant of the same Transmission (6R Family) with an adapter.

GM redesigned the ZF unit in many ways, and actually made it worse (mainly cheaper/ designed to fail at aprox. 100,000 Miles).

 

No wonder it doesn't work right. It has NO FORKING CLUE what the driver is asking for or what the engine is wanting. It's BLIND to everything in the world except vehicle speed. It has absolutely no chance whatsoever of ever working right.

All that aside...

If you're putting a LS3 into a car that didn't come with one, I'd suggest looking at cars that the LS3 and its ECM and harness DID come in, and the transmission that was bolted up to the LS3 in those cars.

Can't comment on tunnel mods or that sort of thing; only, what hooks up to the wiring, what the ECM is expecting to control, and so forth. I'm kinda thinking it would make the best sense to try to adapt that transmission, whatever it is, into my car.

 

I missed who Posted about Constant-Pressure Valve-Bodies...
I am assuming it was in regard to a THM700-R4, or even possibly a THM200-4R Transmission.

I do NOT recommend using a Constant-Pressure Valve-Body; as in a TCI type of Constant-Pressure Valve-Body.
There actually are ways to properly modify the Throttle-Valve Valve-Train, so that the Throttle-Valve Cable is only used for Shift-Timing, and nothing to do with TV-Pressure and Line-Pressure.

I would modify the Valve-Body in this way... if a Trans-Brake was going to be used, or some other special scenarios.

With some of the TransGo Parts for the Throttle-Valve Valve-Train, and some of my personal modifications...
The Throttle-Valve System actually works very well.

If anyone here actually needed a Valve-Body that was properly modified, so that the TV Cable does not effect TV-Pressure and Line-Pressure...
PM me, I will build a Valve-Body, or modify one sent to me... Then I would have you guys go through Dana of Pro-Built Automatics for payment and shipping the Valve-Body out.

 

I have an LS3 with a 6L80 in my 1991 Camaro vert. The 6L80/90 is more work and money but the end result is very good. You can run a highway friendly rear gears and with the 4 to 1 first gear and LS3 torque still find yourself traction challenged.