Ok so here goes my list of issues. When I come to a stop or slow down significantly my truck will die. I mean like someone turned the key off. Put truck in neutral and it starts right up and drives. I have noticed you have to push rather hard at times on the accelerator to get the truck to take off, once it does it really takes off, like its parking brake was released. At times on idle the rpm needle bounces and the engine revs. On one occasion my truck would not shift without letting off the gas. I also get intermittent hard shifts.
Here is the good news: I have a brand new transmission with less than 12000 mile ford reman that has a warranty.
Here is the bad news: Ford Conveniently can't find anything wrong with the truck. Even though when I drop it off it's doing it and shortly after I pick it up it is doing it.
Here is my opinion: It sure seems like Torque Conv, but being that it can literally go a couple months between episodes I feel it has to be some dreaded electrical issue.
That doesnt sound like just the transmission, you may have multiple failures. When the truck stalls does all the gauges go dark with all the lights or does the truck just stall while all the gauges and lights still operate?? The Charging system (alternator and battery) work like this. The battery starts the engine and when the engine is spinning the alternator runs the vehicle. If your alternator is intermittently working over time the battery will inevitably lose its charge because the alternator wont charge the battery properly. When the battery is dead and that alternator cuts out the truck will die. you could also just have lose or bad wires at the battery terminals.
Hard shifts can be caused by many things. Could be the electrical problem above or could be problems in valve bodies in the transmission or even boost/ vacuum leaks. You say that the tranny was rebuilt, why was it rebuilt and what were the issues it had before the rebuild?
The gauges do not go Dark but they do dim a little. The truck just stalls dead as if the key was shut off. This is intermittent. I finally found a mechanic that is interested in helping me. He has had the truck now for a couple of weeks. It has acted up for him a few times. He said he is getting a lot of noise on the one wire that comes into the PCM that is not constant power whenever it is acting up. He will not have anything when it is acting fine. He is using an oscilloscope. He is wanting it to act up again so he can see what the constant 12v power wire is doing to further his investigation. When it acts up it also shifts hard. I believe the reason the transmission was changed was because of this problem. Its a Ford Reman and under warranty. It was taken into Ford by the original owner after the transmission was replaced for 21 days and they found everything to be fine. Then he offered it for sale online, and passed his problem to me.
The other thing I noticed when it really acts up if you put the truck in Park it will rev up and down all on its own. I have some videos I will try and post.
i had some odd problems like that with my 7.3 when i put an autozone crank position sensor in it. truck would randomly die especially after turning the wipers on and when it would shift gears.
I had an old car that would do that when I stopped. It would just die. Put in neutral and fired right back up. Torque converter was bad on it. Hope you figure it out soon.
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