Okay, I have a 1996 f150 5.0 with the e40d automatic in it. this is the second transmission i have had to put in it and still doesnt seem rite.the first "rebuilt" one blew out n i got another one to replace it. it is a rebult e40d with tranny cooler in it and also a new torque converter. It felt great for a few weeks untill i just took it out and when you stomp on the gas pedel to the floor it shifts from 1-2 ok but hesitates and will hit rev limiter when going from 2-3 untill you let out of it, then it shifts fine, then shifts to the other gears ok. I have had a problem before with when i would take it in and out of overdrive the overdrive light would flash n would shift hard. but when i would shut the truck off and restart it would be fine again. im not sure if thes are related problems or not. Is it some kind of sensor acting up and going bad? or maybe a vacum problem when the accerator is all the way? NEED HELP! thanks, Chad

 

drain the pan and converter and change the fluid and filter...put good fluid in and 2 quarts of the Red Lucas trany additive...it will go away and be normal...

 

thats what i thought but i had just changed the fluid about a week ago... could it be a sensor??

 

VSS in the rear diff is extremely important for proper shifting. Same sensor for the speedometer.

 

would that cause it to only happen between 2nd and 3rd gears? and i also noticed that while up to speed in overdrive it seems to be fluctuating and feels kinda like it is dropping in and out but still remans in overdrive

 

The torque converter is probably locking/unlocking. The tranny will do weird things if that sensor is bad.

 

did you drain the converter too...?

that trany holds 18 quarts of fluid and only 6 in the pan...if you just drop the pan...it doesnt really help

 

If you missed that part, it's very important...

Again:

"put good fluid in and 2 quarts of the Red Lucas trany additive...it will go away and be normal"

My 2nd to 3rd shift in my 4R70W did the same thing, I put 1 Quart of the Lucas Tranny Fix in mine and it INSTANTLY fixed it, no kidding...

 

Ill try the sensor thing in the rear then. I did indeed drain the torque converter because it is a brand new torque converter also. everything is rebuilt ans has fresh good fluid in it. I added the stop slip lucas red in it but still does the same thing. I also heard that a pinched vaccum line could cause this? thanks guys

 

I agree with the VSS sensor in the rear diff. I had a thread open for a while about that sensor and it ended up that the sensor itself wasn't bad, the wires running to the sensor were broken and needed to be replaced. The mechanic at the trans shop said that this is common, especially in long bed trucks due to body flex. I would start with the wires that run from the sensor to the main harness running down the framerail. If that doesn't work, trace the wires back and run complete new ones.

Here's the link to the thread that I mentioned:
https://www.f150forum.com/f10/speedo...strange-14236/

I want to note too, that I did replace the sensor with a cheap, cheap one and it made my problem worse. My original problem was the speedo fluctuating but with that POS sensor, my trans was acting all kinds of retarded!

I also had a vacuum hose come off on my throttle body and that caused the trans to downshift weird too. I just put it back on and everything was fine!

Hope this helps,
Tony