1996 f-250 5.8. rebuilt trans still doing what it was before. Now i am rebuilding the whole truck trans and engine new panels interior and paint.completed,so it at 325 thousand kms i started with the trans as it was already giving problems. the trans only manually shifts 1-2. if you have it in drive after say 40 miles per hour the engine revs high and acts like its in neutral, manual shift in 2nd and drives fine up to 50 miles an hour but then its at rev limit.trans shop said the main computer is the issue. pulled old one and it did have some corrosion signes on top of unit, order replacement from flag ship one , the unit connections looked dirty and plastic plug where harness goes into had a crack , so much for rebuilt and reprogrammed.the trans shop is ruling that out.they changed the vss. they did not know that i did that a year ago when the speedo was bouncing as soon as the truck was doing 45 miles an hour. The shop says the scan tool they have is showing the vss but is not showing speed this truck is a few months before OBD2 came out some later 96s have OBD 2, this truck is still the old body style that changed in 98 for 250 and 350. the f-150 in 96 had the new style update. i hope some one can suggest where to look. 5 grand plus spent on trans /computer and cant drive the truck, still at trany shop parked out back . they are stumped but helping.thank you.

 

Have you checked for engine codes? Both engine off and engine running. It may give you a direction to look in. Your symptoms vaguely reflect a transmission that's not getting 12v.
​​​A common problem for these trucks is the wire harness that feed the solinoid pack on the passenger side of the transmission. It needs to be carefully inspected to insure the insulation isn't damaged and shorting out.
If that doesn't lead you to any clues, you'll need to pull out your multimeter and start checking ohm on the wiring harness and solinoid pack.

 

What is the line pressure at?

You've got manual gears 1-2, but nothing when in D.
Veryify wireharness as above, solenoid pack, VSS, PSOM.

 

Hello fellas thanks for the help, i will let the trans shop know what you said and find out the line pressure.had to lookup what a psom was, now when i had the bouncing speedo i changed out the cluster with my other truck that was in a t-bone accident, twisted frame. thou lots of spares, i will look more at psom issues/repairs. Mr White thanks for your reply this is my first post here did not notice a location when i joined. same neck of the woods, i see. could you please give Alex or Don a call @ Alberni Automatic.ill send out or drop of a Philips taster pack for your trouble. thanks

 

There are several possible causes for these issues. It is possible that there is a problem with the transmission control module or with the wiring or connectors that connect the VSS to the transmission control module. It is also possible that there is an issue with the transmission itself, such as a faulty shift solenoid or a damaged gear synchronizer. I recommend having a mechanic diagnose the problem and determine the cause of the issue. They may need to use specialized diagnostic equipment to pinpoint the cause of the problem and determine the best course of action to fix it.

 

A damaged gear synchronizer? I thought I knew automatic transmissions, but I have never heard of a gear synchronizer in an automatic transmission. What does it do? How does it do it? Are you sure you didn't make that part up?

There are codes stored. Without knowing what codes are stored nobody is going to be able to fix this.

 

in the o p i made mention that the transmission is doing the same thing after a 4 grand rebuild, but have since also spent money on a replacement main computer. the trans has a new solenoid pack installed. its freezing, and trying to snow now, limited time ,but i will check the other help that has come in and hopefully will post answer for others. as well keep the ideas coming in thanks all.

 

only have first and second gears and only when in manual 1 and 2. The connectors at the transmission are in bad condition. You aren’t getting the VSS signal from the sensor to the computer. It sounds like an electrical problem to me and yet they sold you a rebuild and a PCM?

 

Here's my abridged E4 story somewhat similar to yours.

For years my 94 would go through periods of come & go varying levels of hard shifting then normal operation with a plethora of 600 trans codes that came & went as well.

Till eventually it began the slipping/no output business & recorded zero trans codes, so I had it rebuilt & it still ran like crap.

It took both computer, then a PSOM (95) out of the junkyard which also cured my bouncing needle.

I'd be hunting up another computer or two, PSOM & maybe a new/used motorcraft MLPS if aftermarket is on it now.

All wiring & connectors are in good shape? MLPS switch alignment?

Also is this a OBD II MAF 5.8 as asked before?

 

1996 5.8 is going to be Speed Density OBDI (one), I am 99% postive without seeing the truck.
Transmission connector plugged in?
Hopefully not a 1994 computer with a 1996 solenoid pack, that will fry the PCM.

 

He's in Cali which means it's better to just ask & verify.

 

Nope, CA is Canada, BC, British Columbia, and the transmission shop is in Port Alberni.

 

Sorry I missed the bc.

Still like to have a positive ID from OP.

 

If I spent 4 k on a trans job that didn't repair it, I would be talking to a lawyer. Is this shop owner a personal friend, or at least given you a 100% guarantee they will fix it ?

 

ok hang on a bit. iam restoring the truck all new door seals , fenders, etc,its been painted. i wanted to rebuild the trans ether way, and also the motor and some how reset the odometer back to 0000.so this problem made it sooner on the rebuild. what i wasn't expecting was the PCM, cost by the time with money exchange cost just under $700.Canadian dollars. the truck is still at the trans shop, i have used them for other jobs for many years and are upstanding guys, but they are still stumped on what needs to be done. they said the harness was check for broken wires not sure yet if tested foe 12v at solenoid.