Transmission help

[Lamont_24]

My truck was shifting like a dumbass for a little while so I changed the axle speed sensor and that helped but made my speedo jump around and now sometimes my truck will jump out of gear while cruising or accelerating and then a couple seconds later jump back in, is it the solenoids or transmission speed sensor? It doesn't slip at all and it shifts good it doesn't slip it but sometimes it will slam in

 

[Mark Kovalsky]

Are there any error codes in the computer's memory? The jumping speedo is a clue. The PCM uses that signal to control the trans. It has to be a good signal, no jumping allowed.

 

[Lamont_24]

Okay that's good to know, I'll have to get a scanner on it somehow, the check engine light is on so that's a good clue to that too

 

[Lamont_24]

Hooked up an edge to read codes and this is what I got
P1280 injector control pressure circuit out of range low
P0500 speed sensor malfunction
P1748 no description
P0470 exhaust back pressure sensor circuit malfunction
So I cleared them and I'll see what comes up after driving again

 

[old man dave]

The original VSS was metal. The present replacement is plastic. Sometimes the new replacements work and sometimes the speedo jumps around and cruise does't work. In these cases, you may have to go to a wrecking yard and get an old metal housing one. However, I replaced mine with a plastic VSS and it worked. Its a crap shoot. Welcome to the Wonderful World of Fix Or Repair Daily.

 

[Lamont_24]

Well the speedo stopped bouncing around, and today my truck stopped shifting into 3rd and then jump out of overdrive. I checked the codes and it's throwing the vss code again so maybe it's the sensor on the transmission? Thats at least what I'm hoping it is

 

[Mark Kovalsky]

Which sensor on the transmission do you mean? There are several.

 

[Lamont_24]

Isn't there a speed sensor on the transmission somewhere? I heard there's two vss speed sensors, one on the rear axle that I changed and I heard there's one on the trans. But I could have been informed wrong

 

[old man dave]

I think there is only the one on the axle for an OBS E4OD. The SD 4R100 has two, one on the trans also, I think. You also may have a broken wire causing your symtoms to come and go.

 

[Mark Kovalsky]

The 4R100 has two speed sensors on the transmission and one on the rear axle. The E4OD in this truck should have no speed sensors on the transmission and one on the rear axle.

 

[Lamont_24]

Okay that makes sense cause he was talking about them doing it on a super duty now that I think about it. But yeah I'll probably have to test connectors and check for broken wires, thanks for the help

 

[Lamont_24]

So I was driving home from work and its getting worse. It wont shift out of first and I have to shift into 3rd and it will then shift. I decided to check my fluid when I got home and it is overfilled. It's over the whole white check part. Would that be a good reason for my problems?

 

[Mark Kovalsky]

What year is the truck?

 

[Lamont_24]

1996

 

[Mark Kovalsky]

Unless it is grossly overfilled that won't cause this.

You could have a bad transmission range sensor, vehicle speed sensor, or a wiring issue to either of these.

 

[Lamont_24]

Where's is the transmission range sensor located? Cause that sounds like it could be it. It started out in third a couple of times today. Could the solenoid pack being going bad?

 

[Mark Kovalsky]

The transmission range sensor (also called the manual lever position sensor or neutral safety switch) is located on the driver's side of the transmission where the shift cable attaches. It's the part with the wiring harness attached.

A bad range sensor will not make the trans start in third gear.

 

[Lamont_24]

Hmm interesting. I know what sensor you are talking about though. I'll have to look at it. Do you know what would make it start in third?

 

[Mark Kovalsky]

There is nothing that will make it start in third gear. I can't think of a way that can happen.

If there is no power to the shift solenoids it will start in fourth gear, but not third gear.

 

[Lamont_24]

It could have been fourth gear. I didn't get to go over 30 mph cause it was a stop sign with a sharp turn, but it sure did bog down. So would it be a good idea to drop the pan to check the solenoids?