E40D upshifts before it should
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E40D upshifts before it should
Two days ago I noticed that shortly after I take off from a stop, my engine bogs down. figured out that the transmission is shifting into the next gear before it should. the only thing i did before this started happening was change the alternator. when I was removing said alternator, I caused an arc from the hot leg of the alternator to chassis ground. Would this cause the computer to do something weird like this shifting problem and can I reset it by unhooking the battery for a few minutes? I also noticed that the trans fluid was low after the truck was warmed up so i added fluid to the proper level. (1 full quart)
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From: NE Ga
You can try reseting the comp just to rule it out. The only way you'll ever know if the comp is bad or not, if the prob continues, is to swap comps. If you were just one qt low then you didn't hurt anything by that. Always always always pull the - before doing anything electrical. I smoked my whole harness from the alternator to the regulator when i tried doing a "quicky" regulator swap. Learned my lesson needless to say.
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is there anything else that could cause this problem? maybe a bad sensor somewhere? it has also been very wet here the last few days. maybe I got something underneath too wet. there were some pretty big puddles out there.
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I don't think so. If it were that easy to corrupt a tranny, then you'd be hearing of alot more cases of moist tranny problems. Check your vacuum line/s going down to the modulator valve on the tranny body. Could be coicidental that one broke or is now leaking. I'm more familiar with C6 trannys but have changed out many E40D's. I'm not sure if this is possible or not but if your speed sensor is going wack even though you're gettin the proper speedometer reading, it could be sending bad signals to the comp causing it to upshift sooner than it should. Unlikely and I'm not sure if possible.
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Originally Posted by 73F100*8Mile
Check your vacuum line/s going down to the modulator valve on the tranny body.
Originally Posted by 73F100*8Mile
I'm not sure if this is possible or not but if your speed sensor is going wack even though you're gettin the proper speedometer reading, it could be sending bad signals to the comp causing it to upshift sooner than it should.
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Thanks for the insight. I disconnected the battery for a couple of hours.(forgot to go back out and hook it up). Problem has not reared it's ugly head since the computer reset so I am crossing my fingers hoping that it will not return. Thanks again for the help.
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problem has returned. it goes away after the trans is warmed up. (a couple of miles) could it be the throttle position snesor or the throttle position valve? I had the tranny flushed and the filter replaced yesterday but the problem is still there. this thing is 11 years old. I can't be the first one to ever have this problem. has anyone ever heard of this happening before?
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From: Malvern, Ohio
well 1 - 2 shift generally is 12 - 16 mph under regular throttle, 2 - 3 is around 24 - 28 im pretty sure. If its shifts sooner you want to look at everything tied in to the tranmission because you don't know what happened when you caused an arch. Just check what you can man. good luck
