47re converter erratic unlock/lock in 3rd gear with OD off
As the title states, this lovely problem just started. Before I go any further I want it to be known that the brake switch is brand new, and I made sure to hold the pedal up with my foot to rule that out.
I can repeat the problem like clockwork if I turn OD off and go up a hill with medium to heavy throttle. It unlocks then locks quickly, repeatedly. I don't want to do it too often as it bangs pretty hard and I don't want to hurt the transmission. I do have a manual lockup switch and if I turn that on the issue completely goes away.
Knowing that a bad alternator can cause lockup issues, I tested my charging system. Both batteries were at 12.68 volts with the engine off, and when I start it it sits at 13.97 volts with the alternator charging. When the grid heaters cycle, the 13.97 volts drops to 12.68 then back up to 13.97. I am not sure if this is too low as some others report it is supposed to be over 14 when the grid heaters are not cycling, and shouldn't drop below 13 under load. It should also be known that I have an el cheapo Innova multimeter.
All the grounds are fine, and I checked the voltage drop with the multimeter and it was .04. All of that seems to check out, so my next course of action is to drive the truck to the hill where I can get it to do it every time, and then pull the fuse to the alternator and see if it still does it. If it does not, then I would think it is the alternator and perhaps a bad diode, but I'm not sure how unplugging the alternator (fuse) might affect other systems.
I know the TPS can affect lockup, too, but am unsure why it would only be in 3rd gear, not OD, when the throttle is in the same spot. I tried some heavy acceleration in OD and it never did it, but I can't find a steep hill where I can safely get enough speed in OD.
Suggestions appreciated. Will post more as I try to work my way through this. These are the kinds of annoyances which push me into brand new vehicles as I tire of the constant troubleshooting and tinkering. A G56 would be so nice...
As the title states, this lovely problem just started. Before I go any further I want it to be known that the brake switch is brand new, and I made sure to hold the pedal up with my foot to rule that out.
I can repeat the problem like clockwork if I turn OD off and go up a hill with medium to heavy throttle. It unlocks then locks quickly, repeatedly. I don't want to do it too often as it bangs pretty hard and I don't want to hurt the transmission. I do have a manual lockup switch and if I turn that on the issue completely goes away.
Knowing that a bad alternator can cause lockup issues, I tested my charging system. Both batteries were at 12.68 volts with the engine off, and when I start it it sits at 13.97 volts with the alternator charging. When the grid heaters cycle, the 13.97 volts drops to 12.68 then back up to 13.97. I am not sure if this is too low as some others report it is supposed to be over 14 when the grid heaters are not cycling, and shouldn't drop below 13 under load. It should also be known that I have an el cheapo Innova multimeter.
All the grounds are fine, and I checked the voltage drop with the multimeter and it was .04. All of that seems to check out, so my next course of action is to drive the truck to the hill where I can get it to do it every time, and then pull the fuse to the alternator and see if it still does it. If it does not, then I would think it is the alternator and perhaps a bad diode, but I'm not sure how unplugging the alternator (fuse) might affect other systems.
I know the TPS can affect lockup, too, but am unsure why it would only be in 3rd gear, not OD, when the throttle is in the same spot. I tried some heavy acceleration in OD and it never did it, but I can't find a steep hill where I can safely get enough speed in OD.
Suggestions appreciated. Will post more as I try to work my way through this. These are the kinds of annoyances which push me into brand new vehicles as I tire of the constant troubleshooting and tinkering. A G56 would be so nice...