Auto supra stopped shifting on its own, and speedo isn't working?

[suprafanatic]

So this is my first auto supra, I don't know hardly anything about the auto's. One day I was cruising on the interstate at like 70mph and the speedometer just dropped to 0 and my RPM's shot up. I pulled off to the side of the road, turned the car off and back on. Put it in drive and it starting moving, but it wouldn't shift out of 1st gear, and the speedo wasn't reading anything. So I unplugged the computer for the transmission and I am able to manually shift it from L -2 - D. I guess I'm wondering if a broken speedo cable would keep the car from shifting on its own since its all electronic?

Thanks, Nate.

 

[Rollus]

Hi,

Transmission works without speedo, but it is all hydraulic then. Gear are then shifted according to rpm and throttle position.

What do you mean by rpm shot up?

 

[Poodles]

Yarp, it needs the speed signal from the speedo to function correctly.

 

[Mfendo]

I have the a134e auto trans, my speedo stopped working but it still shifts and pulls like a beast. Maybe its because the cable snapped in a different location?

 

[ATL88Supra]

speedo cable(check for a broken cable) or the plastic gear in the rear extension housing wore out

 

[suprafanatic]

I mean the RPM's shot up because the car was no longer in a higher gear. As soon as the speedo stopped working the RPM"s jumped up so the trans basically jumped to 1st or 2nd gear and wouldn't shift out of it. Both things happened at the exact same time. So i'm assuming its related to the speedo cable braking, or the gear for it going out.