4L60E Question

HeyBoom · June 2, 2004

I'm getting ready to build a 400ci SBC for my '92 Z71. My question is, will the trans hold up? Looking for roughly 380 - 400 hp & 385 - 450 ft lbs of tourqe. Any suggestions here would be greatly appreciated.

robsawatsky · June 2, 2004

If you really think your going to get that much torque, it is too much for a stock 4L60E. You can get stronger rebuilt versions with 3rd party parts or maybe a different tranny. Can't tell you what would work with a vehicle that vintage and what would be necessary due to the electronic tranny control.

TarheelZ · June 2, 2004

The electronic version didn't come along until after '92 though, right? Not to say that the 4L60 was any stouter, necessarily, but they can be 'built' to strengthen them, as Rob says.

snoman · June 2, 2004

I'm getting ready to build a 400ci SBC for my '92 Z71. My question is, will the trans hold up? Looking for roughly 380 - 400 hp & 385 - 450 ft lbs of tourqe. Any suggestions here would be greatly appreciated.

It should handle any torque for a non supercharger small block just fine. The 4L60E is based on the 700R4 which was based on the THM 350/375. THey are stouter than people give them credit for and those that fry them usually abuse them and do not have proper aux cooler on them as heat is the number one enemy of auto trannies. Keep it cool and it will handle a lot of reasonable abuse. Beside the 4L60/65E have a 3.1 first gear which is real great for take off and off road. The 4L80/85E is only 2.48 in first.

maroonsilverado · June 2, 2004

if it's still stock from 92 i would say it wouldn't hold up. cause if you're like me you like to use the power you have on tap . so if you dont have the cash to get it rebuilt i'd take it easy when you put the engine in until you get it rebuilt. now once you get it rebuilt and throw a shift kit in it it should hold up fine. that's alot of horsepower and torque dont get me wrong, but that's not too terrbily much either. just be sure and tell the person that builds your tranny your purposes and the power you're putting to it. like someone said, the 4L60 was based on the 700R4, and i know a guy that's running around 450-500 horses on a 700R4, but he's had it built to handle the abuse. so it wouldn't hold up for very long in it's current condition, but once you get it built it should handle without a problem

HeyBoom · June 13, 2004

Thanks for the input guys. I guess that after the engine is installed, I'll have the tranny gone through. Thanks again!

snoman · June 13, 2004

if it's still stock from 92 i would say it wouldn't hold up. cause if you're like me you like to use the power you have on tap . so if you dont have the cash to get it rebuilt i'd take it easy when you put the engine in until you get it rebuilt. now once you get it rebuilt and throw a shift kit in it it should hold up fine. that's alot of horsepower and torque dont get me wrong, but that's not too terrbily much either. just be sure and tell the person that builds your tranny your purposes and the power you're putting to it. like someone said, the 4L60 was based on the 700R4, and i know a guy that's running around 450-500 horses on a 700R4, but he's had it built to handle the abuse. so it wouldn't hold up for very long in it's current condition, but once you get it built it should handle without a problem

It will not hold up if you are running 3.42 or 3.73 and tires too or if there is no aux cooler. A "super" is no sub for poor gearing and will only strain tranny even more.