I was having problems with my truck and finally narrowed down the problem to the trans. I will be cruising down the road generally around 35-45 MPH and the trans will downshift for no reason for about 2 seconds then it will go back to normal. This happens at random times in OD or out of OD. I dropped the trans pan, changed the fluid and filter and Im going to put an additive in and see how it runs. Does anyone know what the source of this problem could be? Truck is a 96 5.0, e4od auto. Thanks, Dave

 

That transmission is COMPLETELY computer controlled and it doesn't do anything unless commanded to do so by the computer, so step #1 is pull the codes.

 

Are you sure it's an e4od
I had an explorer do that (4r70 trans) and it was low on fluid and tps was bad.
Try to avoid additives, it's a bandaid, and some just swell the seals and clutches to make it "work" better. When in the long run hurt it even worse for when you actually figure out the issue.

 

I will get codes pulled today and see what it says. It is the e4od and the fluid level is good and I replaced the tps not to long ago

 

what your describing is most likely the torque converter unlocking/locking.it should set the converter slip code at least.
it is supposed to un/lock around those speeds.however it shouldn't be doing so if your speed is steady and remains above lockup speed.

a simple test to see if it is the torque converter unlocking when it shouldn't be;
turn on the hazard lights and drive up to 45mph.this will keep the converter from locking,while allowing the trans to enter OD.
if all seems to be fine without any of the downshifting issues when it shouldn't be,then you'll know the issue is with the converter or the electrical system that controls it (which is most often the case.)


what you want to do is inspect the main trans harness connector (also known as the bulkhead and solenoid pack plug) often this harness fails here or is simply dirty.remove the heat shield and push inward from the outside in,on the clip,while also pulling up to safety remove the clip without damage.very,very carefully inspect for and repair any corrosion.it is vital that the pins in the plug on the harness are cleaned,but don't forget the pins down inside the pack.use a small mirror to inspect their condition.electrical cleaner & dialectic grease.if you see any frayed wires,replace the connector.

Failed shift solenoid pack plug.
This is an example of what you don't want to see! This is the main harness that the ECM uses to communicate with the transmission. If yours looks like this one,google search:
E4OD solenoid wire harness repair kit

 

Does your speedometer needle ever bounce around a bit?

 

Not trying to hijack, but what causes the speedo to bounce every now and then on a 96 F350 460 w/C6?

 

It could be..

A failing speedo
A failing PSOM module
A Failing VSS sensor
A wiring problem between the VSS sensor and PSOM

 

I would not put additive I did in my old truck and it made matters worse. My e40d was searching and hard shifting and found the TRS plug had come loose.

Bouncing needle happened to me too. Changed the VSS and it fixed it immediately.