heavyduty Posted January 3, 2016 Report Share Posted January 3, 2016 Does anyone know is there a good way to test a voltage doubler on a fredomline transmission. It throws a sm code and audible alarm every once and a while mostly after it shifts in to 12 gear. I have done all normal things like cleaning all cables and grounds. If I pull codes on the trans ecm it gives 39 and E7. If I am looking that up correctly it says loss of communication between trans and shifter. Any thoughts would be appreciated. Link to comment Share on other sites More sharing options...
GoldRush Posted January 3, 2016 Report Share Posted January 3, 2016 Have you checked the resistance of the wire harness from the transmission to shifter? You could have an intermittent open or short somewhere along the harness. Link to comment Share on other sites More sharing options...
Phil D Posted January 3, 2016 Report Share Posted January 3, 2016 I'm with GoldRush on this one. If you had voltage doubler problems you'd have no shifting at all due to the lack of 24 volt power, but it shouldn't be erratic. You have an electrical fault somewhere between the "Astronic" box and the transmission itself, not a voltage problem. Link to comment Share on other sites More sharing options...
Big5er Posted January 3, 2016 Report Share Posted January 3, 2016 Sorry Phil, but WRONG!!! I lost the doubler in Kansas 2 years ago, remember?? I spent forever trying to figure out my intermittent issues, almost a year. Sometimes it wouldn't "shift" into neutral when I turned the key and other times I would be accelerating when it would suddenly throw codes and fail to shift anymore. It would display "SM" on the dash and be stuck in whatever gear it had been in. I would stop and sit for a few minutes and as it warmed up it would stop acting up. Finally in Kansas, the day I was planning to head home it just went totally goofy. Heavyduty, when my went to hell, I called my mechanic at home and told him the codes. He "guessed" it was the doubler and told me the only wayt to know for sure was to have a Freedomline mechanic plug it into the computer and check it. I had mine towed from Hutchinson to Wichita. They confirmed that the doubler was bad. Here is the thread about it at the time, including where to find a cheaper than dealer priced voltage doubler. I bought it online for about half of what the dealers wanted. Link to comment Share on other sites More sharing options...
heavyduty Posted January 3, 2016 Author Report Share Posted January 3, 2016 Thanks all for replys. This thing is about to drive me to drinking doctor peper. It is intermittent and will always shift and the sm code only last a few seconds and always clears itself. My volvo dealer in Joplin mo said they had not a clue. Might just take a chance and through a doubler at it or wait till it gets worse ???? Link to comment Share on other sites More sharing options...
Phil D Posted January 3, 2016 Report Share Posted January 3, 2016 Thanks for clearing that up, Big5er. Yours was the one that I had in mind when I read his post, but I thought that yours was fine until it failed, not an intermittent problem. Link to comment Share on other sites More sharing options...
Brad & Jacolyn Posted January 3, 2016 Report Share Posted January 3, 2016 When mine failed the engine would not even start. They told me that since the transmission did not know where it was it might even think is was already running and would not engage the starter. Brad Link to comment Share on other sites More sharing options...
heavyduty Posted January 5, 2016 Author Report Share Posted January 5, 2016 Ha Big 5er did that aftermarket voltage doubler that you used, did it come with proper plug conections or did you have to rewire anything. Doesn't look that hard to change just 4 bolts and a wire plug or am I missing something. Link to comment Share on other sites More sharing options...
Big5er Posted January 5, 2016 Report Share Posted January 5, 2016 It looked like the one on top of the tranny. I let the dealership where it was broke down change it out, so I did not examine the plugs but they looked the same. It was the same part number just without the "ZF" . My mechanic said any good freedomline mechanic would change it from the bottom, but the access port in the floor makes it real simple to find. Link to comment Share on other sites More sharing options...
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