I am about ready to drive my F150 off a cliff with me in it. I am so tired of trying to find the solultion to my problem.

I have a 1994 F150 extended cab. It is a 5.8 liter and a 351 with rear wheel drive only.

I bought this truck used from Ford about 6 years ago. From the first week I had it, I noticed that SOMETIMES, it would buck wildly and slam into the gears when it shifted and make a revving noise like it wants to shift but is delayed. This problem would go away after driving for a while at which point the truck would run perfect.

I took the truck back to Ford the following week after buying it since it was under warranty and Ford told me that it was the transmission and that they would replace it with a new transmission.

A week later, the new transmission was in the truck and about a week later, the truck started slamming into gear again once in a while. Since I only used the truck once in a while, I got used to it and learned to live with it. I figured since Ford looked it over, it woudn't be bad to continue to drive it.

Since then, I have just gotten fed up with this gear slamming and bucking when the gears shift. I started doing my research again because I can't continue with this problem.

I took my truck to a reputable transmission shop in the hopes that the truck would make the bucking and gear slamming issue with the transmission guy in the truck with me. Of course, the truck made the symptoms all the way the shop and as soon as the mechanic started driving, the truck ran like a dream.

One good thing is that the expert machanic stated that the transmission is working correctly. He told me that it could be one of the following:

1) Bad ground straps which could send a bad signal to the trucks computer

2) Rear speed sensor

3) Bad TPS switch

Well, I changed the speed sensor and said a prayer and took the truck for a test drive. STILL HAVE THE SAME GEAR SLAMMING ISSUE !

After this, I changed and wire brushed all of the ground straps. took the truck for a drive and I STILL HAVE THE SAME PROBLEM !

I was ready to replace the TPS sensor, but it is located in a hard spot to get to, so I had my brother-in-law who is a mechanic come over and hook his code computer up the the truck for a diagnostic.
The result was that there was NO BAD CODES. My brother-in-law told me that the TPS switch must be good or else it would of shown as a bad code.

Can anyone please tell me what the problem is that I am encountering?? I am sick to death of replacing things and still having the same issue.

I am placing all of my hope that someone on this site will be able to help me out.

Thank you in advance,
Chris

 

if you hook it up to a better diagnostic machine, it should be able to pull a code in the memory, that is if you get a check engine light when your truck has a seizure, lol

 

i dont think either the KOEO or KOER tests would help you with diagnostics. it could be linked to the computer.

 

torque converter

 

Would'nt the torque converter also have been replaced when the new transmission was replaced?

Can a TPS switch be bad on and ofeven if a diagnostic computer does not show a bad code? Can I beleive the diagnostic computer the mechanic uses?

 

They will not replace the torque converter unless they think that is the problem.

 

There is a netural safety switch on left side of trans where the shift linkage hooks up. It tells computer and trans what gear it should be in or is in. I would replace it or check it out {cheap and easy}. My 94 would do almost the same thing and that fixed it.

 

I don't know if this applies to trucks but I had something vaguely similar on a 94 T-Bird. Had it to Ford several times without resolution. Finally had it in a transmission shop and they checked the part of the computer that controls the transmission. They found it was shorting at times which Ford never caught. The final resolution was changing that out and it's been smooth as silk ever since.

Good luck in finding your problem.

Paul

 

I agree with SCOTTYD the range sensor on the driver's side of the trans where the shifter is at gives problems sometimes. They will work fine and then the resistance will intermittantly change and make the trans do some crazy stuff like drop into a lower gear at highway speeds (which would feel like neutral) delayed engagements, no engagements, on and on. So I'd try replacing that and look at the connector to be sure there's no problem with it.

 

My '94 Lincoln TC had symptoms similar to yours. A scan of the system drew a code (667 as I recall) indicating that the MLP sensor was sending signals that were out-of-range. I removed the sensor, cleaned up the connector contacts, ran a bit of oil into the seam between the case and the rotating sleeve, worked the sleeve back-and-forth to exercise the internal contacts, aligned the neutral marks and, with the shift lever in neutral, carefully reinstalled the sensor to retain the alignment settings. The tran now shifts and runs properly and has for the last four years.