have a trans problem, bought the car no overdrive 1-3 shifts good, had a code for neutral safety switch had it replaced still no overdrive. then 3 days later I replaced burnt out cruise control fuse immediately had overdrive for 4 days then went out again but fuse was still good. only yhing I did differently in those 4 days was put a cd in the aftermarket radio someone else put in. the other thing is if I pull it in to first gear and try to shift it manually it will shift in to second by itself without me shifting it to second, im sure it is electrical I just don't know where to start. thanks

 

Do a search on this forum. I'm not too familiar with these Trans but it likes like a pressure control solenoid issue, located in the trans

 

do you mean the shift solenoid or something deeper in the trans, because the shift solenoids are kinda of on the outside of trans and relatively easy to change. thanks

 

How Much Do You Know About The GM 4T65E Transmission?

The link above might help. It shows the Pressure Control Solenoid & the Shift Solenoid locations. It also says why u have no Overdrive: worn splines. But that still doesn't explain why your Trans shifts from 1st to 2nd on its own even when you try to shift manually. If you leave the shifter in 1st will it shift all the way up to drive on its own? Do you have a 4t60 Trans or a 4t65?

 

no if I leave in in 1st it will shift to second but no further, if the splines were bad how could I have had overdrive for 4 days unless some of the splines are bad , maybe? also it shifts fine one thru three, I wonder if when the last guy who put the cd player in went into a wrong wire also if the converter was bad or a solenoid would nt it throw a code. thanks for your help

 

sorry 4t60e

 

Now that I think about it I had a miswired radio play havok with the drivability a vehicle. Start off by pulling the radio fuse. See if that helps at all