Hey guys need some help once again. I have a 95 f 150 automatic, 5.8L. I noticed this evening as I started to drive off the truck seemed to hesitate as it moved forward. Then as I drove down the street I noticed it would not shift into a higher gear while I was going about 20 mph. It felt like it was staying in first gear. I also noticed my speedometer is not working and no odometer reading. As I drove a little further I noticed the off light on the shift lever was blinking, depressing the button on the end did not help. It would ocassionally shift, but very hard. It did seem to run a little better in the 2 setting instead of Drive. After going around the block I pulled into the drive way to see if I had any transmission leaks and check the fluid level. No noticeable transmission leaks (but it is a 95, so it leaks a little oil from here and there). Although the engine was not fully warm I placed the truck in park, ran the truck through every gear, placxed it back in park and checked the t fluid level. It was reading very high on the stick. Engine was running during this process. I'm going to let it sit over night and check it cold tomorrow and see what I get.

I just bought this truck. Dont think it was driven much as is. After the purchase I did drive it home, about 30 miles. Otherwise I've only put an additional 10-15 miles at speeds under 35 mph until this happened. Could it being over filled be causing this problem?

 

The trans in that truck is completely computer controlled and speed input is a critical input, the computer gets that input from the PSOM mounted on back of the gauge cluster and the fact your speedo doesn't function means you either have a sensor/wiring problem at the rear axle RABS/VSS sensor or the PSOM itself is bad.

 

^^ nailed it!

 

So the RABS/VSS sensor is located on the rear axle. Is there anyway I can do a test on the sensor to see if it is operating correctly?

 

You would need an oscilloscope.

Pull the codes to see what's up, if you get a code for the VSS then first check that you have power at the rear axle and if so change the sensor.

 

Some basic VSS testing from Steve83: CHECK SPEED INPUT SIGNAL

 

I check the codes just like I do when the check engine light is on?

 

Yes

The Powertrain Control Module (PCM) controls the engine and transmission when you have a electronic controlled transmission like the E4OD.

 

i replaced the rabs/vss sensor and its still doing the same thing. When I checked the codes I pulled a 452-insufficient input from vehicle speed sensor. Is there another speed sensor somewhere else on the truck?

 

Pull the sensor back out and clean all the rust and junk out from the mounting surface. Mine did the same thing and this fixed it for me

 

No, the VSS sensor in the rear axle is used for the Rear ABS and the speedometer/odometer functions (as well as the cruise control). It's pretty rare your issue is resolved by replacing the VSS. This is another classic example of that.

The RABS module can pull-down the VSS signal before the signal continues onto the PSOM, located behind the instrument cluster. You can measure the VSS signal with a DVM at the PSOM to verify proper signal level. If it is low, try unplugging the RABS module then checking the VSS signal again. If the signal level jumps up, then you have a bad RABS module. If the signal is good up to the PSOM then you more than likely have a bad PSOM.

 

You said you have no odometer reading? Then either your speedometer module packed it in suddenly without warning, or a fuse popped. No speedometer means no speed signal to the computer.

I'd bet on a popped fuse.

 

I've checked all the fuses...they are all good.

"The RABS module can pull-down the VSS signal before the signal continues onto the PSOM, located behind the instrument cluster. You can measure the VSS signal with a DVM at the PSOM to verify proper signal level."

What is a DVM?

 

Digital volt meter..

 

Sorry for using too many acronyms. Here is some info for how to use a Digital Voltmeter (DVM): Fuel Injection Technical Library » Digital Volt Meters