I'm looking at adding a turbo to my 2001 Chevy 1500HD and the common upgrade for the 4L80E transmission is to add an HD2 shift kit. Is there anything in the HD2 kit that I can't do tuning in HPTuners? The only thing I see is the pressure relief valve, which is weird in the HD2 kit and I was planning on using the Sonnax boost valve, which does the same thing, instead. Pressures and shift times are easy enough to change in HPTuners, so what am I missing? Since the rest of the drive train seems beefy, I would like to push between 500 to 600rwhp if possible.

Also, when should I be concerned about breaking the stock 2 piece steel driveshaft? Thanks.

 

If calibration in HP tuners is a claw hammer, think of an HD2 shift kit (or any other proper hydraulic modification) as a jackhammer. Changing settings in software can fine tune shifts, but only within the range of authority allowed by the calibrated hydraulics.

 

The HD2 makes physical modifications to the valve body that dual feeds the direct clutch.

This substantially increases holding power while in manual D3.

There is nothing you can do in HPT that will do the same thing.

The HD2 is actually a dirty way to dual feed the direct clutch. The right way is to pull the trans apart and remove the 2nd Oring out of the center support and plugging a hole.

https://www.performancetrucks.net/fo...l-feed-535430/

 

Made some notes to help explain this better.
Essientially...the hd2 kit is junk. Sloppy mechanics wiki page has a writeup on the do's and don'ts of the HD2

If you're going to do anything...use the separator plate, and that's about it.
Use the sonnax boost valve and also their line to lube PR valve.

 

Only dual feed in D3 not regular D?

 

Thanks, I will look into this. Is there another option on plates that will dual feed in Drive?

 

Not for plates. You can tear the trans apart and do it the RIGHT way.
OR, superior brand shift kit uses some pipe type feed for dual feed...i personally hate it...but it is another option if you want it

 

when i rebuilt my trans i did the HD2 kit, the kit also replaces the direct clutch springs, HD2 + HPtuners shifts are fast and firm my STOCK 4.8 brakes the tires loose on the 1-2 shift @ WOT only thing i did was remove the torque management

 

you know breaking the tires loose on a 1-2 shift hasn't been cool since 1981 right? It's not good for the trans, it's not good for anything really.
Removing torque management is pretty pointless but if you're having fun, who am I to judge.

Reffering to post#5...the hd2 doesn't do anything special do D3 vs D...the direct clutch will be dual fed any time it is engaged. plain and simple.
If you're going to tear the trans apart and replace the direct clutch springs...you'd be absolutely foolish to continue to use the HD2 kit. Because you could internally dual-feed the trans and be left with a much better way of doing things, for a LOT less money.

 

I had a car many years ago that barked every shift, that gets old fast and just bangs the crap out of the rest of the drivetrain. Sounds like I want to just use the HD2 plate ( to dual feed 3rd gear) and Sonnex boost valve to add a little pressure with releaf. Thanks.