I noticed that mine had plastic pistons which I thought was kind of odd for a heavy duty transmission. They looked similar to the pistons of a 4L60E who's to say they are. I've never seen anything about aluminum pistons for the 4L80Es but it seems to be a good preventative measure on the 4L60Es. So whats the deal? Does anyone make them or do I even need them?

 

Good question. Mine has them also.

 

The reason I even ask is because I thought I might have had a cracked one a while back. I have my line pressure turned up but the tables that I thought were the shift firmness tables per gear weren't the right ones (I'm running a modded PCM code) and the 1-2 was just brutal even at light throttle. Once I found the right tables and got the shift pressure in check its all better but still I'm wondering if there is an upgrade for those stupid plastic pistons.

 

I believe GM did use them in the early days but they had issues with them. The updated ones are plastic and are still being used today. Vince

 

Well that about sums it up.