My truck has started shifting way too early. I will be in 4th at like 15 mph sometimes. rpms at around 1000. It has only done it twice in the last week and other times it is just fine. I am looking to pull my camper this weekend and don't want to break down. If it does do it when I am pulling can I just run the auto like a manual. Will it hurt anything?

 

Are you sure your t case didn't get bumped into 4 low somehow? Usually when the VSS goes the speedo jumps like crazy and the shifts are erratic.

 

no its not in four low. I can manually shift fine

 

You can always just pull the VSS out of the rear diff and clean it off. Sometimes they'll get gunk on them and act up.

 

where should I look for the VSS. My chilton manual seldom has any useful info. Is there a better manual with photos for our diesels. should I just use brake/carb cleaner on the terminals? I will look for photos on here.

 

I found info on the vss location so disregard last post. my abs light also comes on occasionally. related prob?

 

Could be from the same thing. The VSS shouldn't be hard to pull out. Just wipe it down good on the part that goes into the axle, maybe put some dialectric grease on the electrical contacts to help keep water out and give a good connection.

Don't remember how much they cost. I got a spare one with my truck when I bought it...

 

ABS light is probably a related problem. A VSS is like $20 or so.

 

just pull it out and whipe it off. Take your time pulling it out, they can break.

 

I tried wiping first and that didn't help much.

It was $22 for a new one and that fixed the problem.

When the sensor wasn't working, the transmission would shift really late. MUCH better than DW's Dodge that just shifted into 2nd and stayed there.

 

You should have the codes pulled, too. The VSS will set a P0500. I've had my tranny downshift at freeway speeds, causing a P0236 to set.

Have the codes pulled and cleared. That way, if something else sets a code, you'll know you have an actual problem to resolve.

 

What brand vss did you buy and from i have tried several even one from ford dealer with no luck?

 

https://www.riffraffdiesel.com/vss-r...-sensor-94-03/

Here you go mate.
Go support RiffRaff, he's one of the reasons we are all here still.

 

Agreed. I have several of Clay’s parts on my junk. Riffraff for the win

 

Yes! Clay is a great guy. Riffraff all the way!