A note about the 4L60E, from our Founder, Frank Cahall...

"CPT specializes on racing and performance 4L60Es. We currently have our Ultra Pro Race builds eclipsing 1200 horsepower in C5 Corvettes.  Yes, the question is obvious. How can we do this, while many claim these transmissions won’t hold up in a typical 300 horsepower application? While the stock 4L60E has numerous design flaws and weak areas, they can all be corrected. The BIGGEST problem with the 4L60E is the huge lack of knowledge and qualified builders. There are too many “builders” out there who are promising things that are above their grade levels. This isn’t a transmission you’re going to build correctly, using an ATSG assembly manual or a YouTube video. It’s also not a transmission that you can just go in a parts catalog and order everything marked “Performance”, and expect it to work and/or last. You’re not going to be flipping burgers one day, and get a job at a big transmission conglomerate and call yourself an “expert” in 2 days because you manage to assemble the parts in the correct order.

I’ve been working with the 4L60E very closely since they came out in 1993. In sharp contrast to many “builders”, I actually have a comprehensive understanding of how they work. This requires knowledge of lube circuits, apply circuits, apply-rate, accumulation, clamping force, apply-pressure, hard parts strength, and clutch, band, and steel material. It’s very obvious when we get inside units built by others that most don’t possess these fundamentals.

Another reason the 4L60E has a bad reputation is due to unscrupulous “builders”. Many would be mortified if they saw some of the sub-standard work we see come through our shop. Those big name brands that use bad, cheap, worn, or damaged parts OR don’t include all the upgrade parts listed in their build sheets. When a customer pays good money, but doesn’t get the build knowledge or parts they’re expecting, they will often blame the transmission design.

A CPT 4L60E is much more than just a bunch of great parts thrown together. It has 25 years of experience, research and development to work with those parts. In this industry, you can be a “leader” or a “follower”. It’s easy to sit back and wait for someone else to solve all the inherent problems, and then just copy their work. Those who do so will never be able to excel. Having the understanding of the 4L60E allows me to be a LEADER. I’ve identified problems and solved them, while others still chase the same failures." - Frank Cahall