Olds64

Hello,

I had a thought today. Is there a way to retrofit or modify an old TH 400 or TH 350 to have an automatic/manual shift option? I am thinking of the newer cars that have a dual range automatic transmission that allows the driver to put the car in D and "go," or to manually shift the transmission by moving the shifter laterally (ie. VW Jetta, Dodge Charger). I know the modern transmissions are controlled electronically; however, I was wondering if there was an aftermarket valve body and shifter combo that allows a person to retrofit their older transmission. I guess this is sort of what the dual gate shifter does, but I don't understand if the dual gate does it mechanically or if there is a mechanism in the valve body that does it... Anybody?

joe_padavano

Any GM automatic can be shifted manually. The dual gate simply incorporates the ratchet stops on the RH gate so you don't miss a gear. There are aftermarket valve bodies and shift kits that will ensure that the trans stays only in the gear you select if that's what you want. The operate by changing the fluid logic that controls the shifting. Newer automatics use solenoid valves controlled by the computer to actually redirect the hydraulic pressure. These replace the vacuum modulator, kickdown cable, etc. This electronic control makes it much easier to shift manually with pushbuttons or paddles.

If you do want paddles (though personally I hate them), there are kits available to retrofit them:

http://store.summitracing.com/partde...art=tci-301441
http://www.superchevy.com/technical/...ers/index.html
http://twistmachine.com/shopping/ind...095726548e047f

Olds64

Thanks Joe. I was just curious. I have a TH 400 book that I was reading through and it does a good job of explaining the fluid logic. I just thought that might be a cool feature.