My 700-R4 is a goner ive blown the 2-3 clutch pack twice now and the now car sometimes wont catch gears right away. I have 450ft/lbs of torque that will increase further one day. I was considering my options and was wondering if the 4L80 or 4L60 can be swapped into a 92 Z28. This is a daily driver that i occasionally beat up on the weekends. TH-400 is not an option for me and a T56 conversion is way out of my price range. Input and links to dealers of these parts is greatly appreciated. Also i heard rumors of cutting to make these trannies possibly fit, is this true?

-Randy

 

Randy, first off, the 4L60 and 4L60E are just the later versions of the 700 R4 used in the 4th gen cars. Bolt up wise they are in essence identical. The differences start coming in the computer controls required to operate them. Talk to Dana at Probuilt, or the folks at Transgo about the difference between these, strenghtening and the requirements for shift control.

The 4L80 is another animal. It is longer, heavier, and requires a specific computer (GM or there's another aftermarket brain and cable at about $900). It is pretty much all electronically controlled. It has a pressure plate with 5-6 snap-dome type pressure switches bolting to the bottom of the valve body for controlling shifting. Also, the 700R4 and 4L60's overdrive ratios are .7, where as the 4L80 is .75 OD.

While I'm sure the crossmembers and tunnel can be modified easy enough, the cost of teh separate wiring harness/ecm, and the cost of the 4L80 itself could put you well past buying a complete 700R4 built up from Probuilt that can handle the power your talking about.

Don't get me wrong, I really like the 4L80 in my 3/4 ton 4x4 Suburban. I've got a transgo shiftkit in it and it really snapped up it's performance.

 

If a T56 conversion is out of your price range then so is the 4L80E swap. A new or rebuilt 4L80E should be around $3000. That's not counting the conversion, computer or torque converter.

Building an engine for lots of power and not building the rest of the driveline will cost you more money in broken parts. If you spend the money on the engine, you need to spend the money on the rest of the parts or you won't be able to go anywhere.