Ok, I have had my truck since June. It is a 5.4 v8 2001 f150 2x4. We had an issue with the transmission so I bought a used one and it was shot so I bit the bullet and had the transmission rebuilt. I got it back 10/31/17 with a 30 day warranty. On day 28 it quit working. Brought it back and the shift solenoid was bad. They replaced it. 24 hours later and it started slipping again and wouldn't go into overdrive. Brought it back and he said something was making it stick open and it wasn't locking into gear. At this point the mechanic mentioned that he thought there was something wrong with the computer in the truck. He said the truck is not showing any transmission codes and that the transmission is not putting out enough volts. He replaced the part that was making it stick open and it ran "ok" for about 3 days. I decided to go get a second opinion but on my way my transmission quit on me again. Now it won't go over 25 mph in drive without slipping out of gear. I can put in in 2nd and it can go up to 40 but after that it really starts to scream. Closest transmission shop is 30 minutes away. My mechanic says that it is not the transmission. He swears it is the computer. Truck has 250,000 miles of the body and 160,000 on the motor. Check engine light has always been on and I know it needs a tune up. But would the computer cause that with tthe transmission? Or am I just being led in a circle so they don't have to redo my transmission?

 

No one is coming clean on this problem.
How do you know what the CEL is all about if you don't get the code?
Why has the transmission shop not read the code if they are competent?
If they have what is it?
Both of you are going round and round without any basis but a malfunctioning transmission.
Until some one does what they are supposed, to you are at an impasse.
We have no better way to help but to get you off the impasse and find out SOMETHING to go on.
Good luck.

 

The transmission is not registering any codes at this time. It was when the shift solenoid when out but after that was fixed it just showed that it is not getting enough volts. He said that the truck is not communicating with the transmission the way it should

 

Houston, we have a problem!
..Not good enough to say the computer is not commutating with the transmission.
Here is why;
The computer monitors' full time' all the electrical functions for crosses, opens, shorts, grounds and stuck solenoids.
There will be a code set for one or more of these if a faults occur as a solid fault.
Question is, is the shop looking for the codes with a proper Scanner?
Does the shifter light come on indicating a transmission fault detected?
These faults are all backed up by codes found in the code list.
If the shifter light doesn't come on, the Computer can't detect a mechanical malfunction unless it affects an electrical function indirectly.
You have to move off this position or nothing will get done.
Your lack of knowledge is being taken advantage by the shop at this point.
I offer you the above as at least a little help to get the issue resolution started.
We still can't help any further.
Good luck.