[JLanzino]

Hey Guys,

I took the truck for a drive this morning and noticed the speedo wasn't working, then noticed the truck wouldn't shift out of 1st, the higher the RPM the higher the speed, but no shifting, Im not sure if its a 4LE60 or 80 on the 1994 6.5 3500 Model. Also I tried the E-Brake and noticed after I took it off and started driving the truck started jumping as im picking up speed

 

[JorgeNY]

Pretty sure all turbo 6.5s had the 4l80e behind it unless its a manual.

You might want to check the VSS and the plug/harness going to it.

 

[JLanzino]

on the 4X4 is the VSS on the Transmission or Transfer case? and after I replace it how do I get it out of limp mode?

 

[nh484000]

there are two sensors. One on the drivers side trans and another on the top of the transfer case. This is likely your problem. Check the wiring, connections, ect.

If the trans has never been dropped and worked on it might be hard pulling those sensors out.

Also your transmission is likely in second gear as its defaults to 2. If you tac it right up it should shift into 3rd

 

[JLanzino]

The Transmission was Rebuilt in 2011 as was the Transfer Case. So the best thing is to replace both VSS and take it from there correct?

If these Sensors are gone, and I replace them how do I get it back into normal shifting mode?

 

[nh484000]

you can test them before you replace them. If you have a electrical meter check the resistance. I forget the value for a working one but your can search the forum. Once you find the problem and fix it it should shift correctly.

Another thing to check is the electrical connection to the tranny. Check your grounds

 

[JLanzino]

I will check all the wiring tomorrow, I was on Rockauto & its just saying the Speed Sensor is on the tranny only for the 4LE80?

 

[nh484000]

the 2wd has two in the tranny i think and the 4x4 has one in the tranny and one in the tcase.

 

[JLanzino]

So The tranny has the Speed sensor, & the Tcase has the Relay I got ya now

So these are what Im after then?

AIRTEX / WELLS Part # 5S4666

AIRTEX / WELLS Part # 5S5404

 

[nh484000]

The bottom one is the one that comes out of the tranny. Just checked mine and it ready 1.4 ohms on the bench. I've never replaced the one in the tcase so im not sure what it looks like.


However, i know if you dont plug it in the truck wont shift

 

[JLanzino]

Is there any way to test the wires going to the sensors before I replace them?

 

[Hardrock2]

JLanzino......

You might want to try just removing and cleaning the sensors.
If the trans was recently rebuilt, there's a certain amount of "fines" that
normally accumulate during break in. Some of them are metallic.

IIRC, these sensors operate on the "Hall effect", and they're magnetic.
Sometimes they pick up metallic debris from the fluid, and either transmit an erratic signal, or none at all. Could save some bucks just by cleaning them.

 

[Tommygunner]

If the spedo is not working the problem is with the rear VSS. Located on the xfer case on 4x4, or the rear of the 4l80 trans on 2wd. The tranny will not shift if the VSS is bad.
Might try cleaning it first as said above.
The front sensor is used for the input rpm, not connected to spedo. PCM uses input from both sensors to tell it what gear it is in, wether the trans is slipping, shift points ect.

 

[streeteg]

on my box truck--- one of the fuses popped and it would stop the truck from shifting out of gear. IDK why--- to be honest--- i found a short in a wire and replaced it and it hasnt done it quite yet---- but check your fuse panel ebfore getting crazy on sensors.