Manual/Automatic Valve Body

[Nevermore]

So, I'm looking at parts for a future restomod because it might be years before I can do anything. I don't know if you'd call it torture or being as prepared as possible for the when the time comes. I tell myself it's all about being prepared and try not to let the torture part bother me too much.

Either way, I'm looking at transmissions and realizing that there's quite a few options. I'll figure out type/brand later. What I'm curious about right now is something I've seen called an automatic/manual valve body.

Does anyone know what that means? Would it operate like the automatic in our cars? I've seen fully manual valve body. I've done some Google research and saw that the manual valve body waits for you to shift, but the clutch is automatic, so no third pedal. I wasn't able to find a difference between fully manual and automatic/manual though.

[pushrod]

http://www.nastyz28.com/forum/showthread.php?t=191319

[Nevermore]

Originally Posted by pushrod

http://www.nastyz28.com/forum/showthread.php?t=191319

Hey, thanks man I appreciate it. I saw this one and it was pretty close to what I was looking for, but it doesn't speak to the actual operation of the transmission, just that it can be shifted manually or kept in full auto. I'm just trying to figure out the difference between an auto with a manual valve body and an auto with an automatic/manual valve body. It's looking like a fine line.

[pushrod]

My understanding is:

auto valve body - works like any automatic transmission.

manual valve body - holds on to the selected gear until changed.

auto / manual valve body - holds on to the selected gear until changed, except there is still a D position, which works the same way that an ordinary auto valve body does. Presumably you lose the "manual" part of the highest gear.

[LSxJunkie]

I've driven a semi-manual valvebody 4L60 GTO. They're a lot of fun if you're into drag racing. However, they do not downshift...nicely. No revmatching, so you'll get a lurch unless you're in the throttle.

With a semi-manual valvebody, the car will hold the selected gear unless it is in D or Overdrive, where it will shift through the gears like an automatic. With a 4 speed like the 4L60, the shifter is set up P-R-N-D-3-2-1. In D, the car shifts like a normal automatic. In 1, 2, or 3, the car will hold those gears. To shift between them, you walk the shifter.