[Scarebird]

you can always throw cubic dollars at it:

6 speed





https://www.jegs.com/i/TCI/890/271701P12/10002/-1

[Sirrotica]

Originally Posted by JLMounce

From a technical standpoint the 4l60e is a better "performance" application, assuming it's built to handle the power. It's gear ratios, especially with the 6 pinion planet are better.

It's designed as a car transmission where the 4l80 is a heavy duty "truck" transmission. That was his main argument.

The 60 will go behind a BOP, you just have to go aftermarket bell, which really increases the price.

Since the 4L80E has T 400 innards with a extra OD gear added it was originally designed as a car transmission in the mid 60s. There is nothing in the internals that didn't come from the much earlier T 400. 75% of the T 400 and 4L80e internal parts are directly interchangeable. So if a 4L80E is a "truck transmission" then so is a T 400 by that standard.

In 1991 when the 4L80E made it's debut, the auto business had changed to 70-80% or passenger cars were FWD and much lighter, with small, fuel efficient engines. That is the main reason that the 4L80E was never used in a passenger car. The design originally came from the big, heavy, large cubic inch, high torque cars of the 60s. Typically the car companies would rather use an existing design, than do a fresh ground up design, so they chose the proven T 400 for the truck lines, and just grafted an OD unit to the already proven design.

It was the mid 70s when GM stopped using the T 400 in passenger cars, and made it exclusively only in trucks with high torque engines, such as BBC, and diesels. CAFE averages forced them to use an OD transmission in the light duty trucks in the early 90s. They had been using the T400 with 3,73 gears in most applications. With the advent of the 4L80E they dropped to a 4.10, and 4.56 gearing as standard gearing.

[Formulajones]

Originally Posted by JLMounce

Agreed, the factory gear ratio drop from 1st to 2nd is pretty suck. However going to the 6 pinion planet changes the ratios. You end up with 2.84, 1.55, 1:0.

I like that, that wouldn't be bad at all.