Did a search, didn't find exactly what I was looking for. Read the stickies, and they recommended going with the 4L60E but didn't say it's required.

When/if I swap in a ls1 or 350, 383 to my thirdgen (haven't made up my mind yet - all i know is that right now the 305 isn't doing it for me anymore and that decision is material for a whole 'nother thread) - do i have to use a 4l, or can I use my 700R4. From what I read, it's pretty much the same damn transmission. Car only has 76,xxx miles on it. Had the tranny inspected last summer, and they said it was in great shape. I hate to go through the trouble to rip it out if it'll hold up and easily mount. I'll probably stay auto with the car..so not really interested in a t56 swap. I'm just not up to speed on auto transmissions. I'm looking for 300-375hp at the wheels, and 350-400 ft lbs out of whatever i end up throwing in at the most.

Thanks!

 

The difference is the "E" part....

Your 700-R4 aka 4L60 is controlled entirely by hydraulic pressure and the governor and the TV cable, except for the cpnverter clutch. A 4L60E is controlled entirely electronically. Those newer motors, and their attached control systems, are expecting to be able to control the trans. That's why you need one.

Mechanically, as far as moving power from the crankshaft to the drive shaft, it's pretty much the same.

Has nothing to do with "HP" or "ft-lbs" or any of that. Much simpler that anything complex along those lines.

 

thanks sofa. so based on what you said, if I go with a basic 350/383 carb'd or efi i should be able to use my 700, but if I go lsx i'm forced into a 4L?

 

You aren't "forced" to a 4L60E if you go LS, but you'd be much better off with one.

The distance from the crankshaft output flange to the front pump changed with the LS1. You can use a spacer to "fix" that, but that means you have a spacer in your powertrain.

The other issue with LS engines is one of the 6 bellhousing bolts of the traditional Chevy V8 isn't there. So, you're down to 5 if you bolt an "old school" transmission to an LS engine. What they did with the LS 4L60E's is make the bellhousing a full circle, with two bolts going to the engine oil pan. Much, much stronger set-up. There is also a way to get around that with the older trans using an LS 4L80E lower cover, but it isn't a direct fit (some modification required).

The beauty of the 4L60E with the LS is the LS PCM is able to make the engine and tranny work together.