Ok, I give up on the 6l80. I can't find anyone who says it can handle what I'm doing to it now with rwhp, weight and big tires and wheels. I've decided to do what everyone else with bigger power does, go 4l80. I only want to do this once so if you guys with expirence can speak up I'd appreciate it. I'm looking at the performabuilt 4l80 for 1000 hp and the rpm level 6. There is a big difference in price and I could just go with the rpm level 5 if I go rpm but I'm over transmission problems and want to move on so I can focus on getting traction. Anyone on here run either trans and have expirence with durability and shift quality? Which way would y'all go and why?

 

Sorry, no experience with either of those units and I run stock 4L80e units in my stock trucks. I've started messing around with these units but just stock rebuilds for now. This is for your 2010 RCSB on your signature, I assume? Pretty light truck relatively speaking, but seems like a powerhouse with those mods!

However, I've done plenty of reading on the subject, along with tuning into the YT channel called Mountains Garage (he specializes in TH400 racing applications, but the rear geartrain for both units is pretty much identical and the guy talks about upgrades borrowed from OEM 4L80e parts.) I would think the input shaft needs to be upgraded to a billet aftermarket and the output shaft needs the rollerized modification at that power level. I don't see that on any one of those 2 options. Dual feeding the direct clutchpack is also a known requirement, and there's different ways of doing that: "shift kit", leaving some seals out+, etc. But the more expensive option seems to have a lot more aftermarket internal parts.

Here's good source for information: 4L80E FAQ ? Jake?s Performance

Are you doing a transbrake?