Waht is worng with shifting
I have a 1994 GMC sierra 1500 with a 5.7 motor. I am having a prolem with down shifting. I get goin about 60 mph and the speedo does not go any higher. It also starts to down shift and shifts back up it just jumps from 3rd to 4th. When this starts to happen the speedo goes down about 10 mph and start to jump around. I had a trans shop test it and it said it does not have any faults. They said it seam to be elctrical. The computer show the speed jumping between 30 and 60 but the speedo said it was 60mph. Does anyone have any idea what this could be before they start palying with. I do not want to have them to start to replace parts untill they figure it out.
Thank you in advance
i have the same truck and problem but it happens when i hit 70. It was a forest service rig and i believe there is a governer on mine. are you sure yours is actually going 60 or could the gears be set at a different ratio so your actually going faster may be your going 70 when it reads 60 and you have a governer. just a thought.
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