4L80e shift kits vs valvebody on full manual set up

[urbex]

Recently put a 4L80E in my '86 K5, and modified the pump along with the wiring to run it as a full manual set up. No computer involved, no automatic shifting, full constant line pressure...though I did learn it would shift on it's own on some level if you forget to hook up the main solenoid power wire, but in VERY funky ways, lol. Thankfully I realized what I did after about an 1/8th mile of driving it.

I've been driving it like this for a few days, and while it works, it's not shifting anywhere near as hard and quick as what I expected it to do. It's a lot closer to stock shift speed and feel than the full manual valve body I was running in the 700r4 that it replaced.

Now I'm wondering if this can be improved with a shift kit, or is the bottleneck in the solenoids themselves, and I really need to go to a true full manual valvebody at this point?

 

[Greg Ducato]

I'm guessing you are running about 140-160 max psi right now ( you can verify with a gauge) and if the valve body is stock you wont experience any dramatic change in shift quality. It certainly wont hurt to operate this way but if you want firmer shifts and increased pressure you will need to modify the valve body and pump.

 

[urbex]

Yep, stock, unmodified valve body. Pump has been modified with reverse boost passage plugged, reverse boost circuit vented, reverse boost valve ground down, and converter drainback hole enlarged to 0.250". No other internal modifications done other than wiring - solenoids connected directly to pressure manifold, line pressure solenoid disconnected.

 

[Greg Ducato]

You will need to replace the pressure regulator spring to get the pressure up. CK performance in New York sells a separate spring you can use.

 

[urbex]

Ahhhhh..that's what that Sonnex valve thing I've seen mentioned a few times on forums is. I'm not pulling it back out now for that, as I'm really not concerned that my weak 350 TBI motor is going to hurt the trans, but I'll likely do that when I pull the motor to swap the 489 in later.

Thanks!