You do know that the oil pressure gauge is just like an idiot light.
When you get 5+ psi the gauge will jump to half scale and below 5psi the gauge will read zero psi.

You can try a VSS but I have yet to see someone fix their problem by replacing it.

I would start by tracing the twisted pair of wires from the sensor on the top of the rear end to the firewall. See if the wires are OK all the way.

As for the temp gauge I would pull the single wire of the sender with the key on and see what the gauge does. Then I would ground the wire and see what the gauge does. One way the gauge should peg and swing the other way on the other test.



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The wiring to the sensor looks okay.. I replaced the rear end speed sensor and drove it a bit. It seems to be shifting fine now, but, the mph needle is jumping all over the gauge... Does this make any sense??

 

Two things will make it do that.
1. A bad PSOM.
2. Bad bearings in the rear end.

Was there any shavings stuck to the old one?

 

Must be the PSOM.... I didnt see any shavings at all.. Fluid was black but no flake.

1.Any where I can get a new one?
2.Is it a part of the instrument cluster?
3.Does this mean the new VSS is not needed and the old is still good?

 

Out of a used cluster at a salvage yard.

No but it is inside the instrument cluster.

More than likely the old one is OK.
I have not seen one go bad yet but a lot are broken when they are taken out. They sure get replaced a lot though.



The PSOM:





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Does anyone know what goes bad on the PSOM?? Like a certain resistor or something that can be replaced?

Seems pretty ridiculous that the only way to fix this problem is with a used part that has the potential of being or ending up the same way..

Also-- This F350 doesn't have a sensor on the transmission in addition to the one that's on the rear end does it?

 

Sometimes a item comes loose from the board and you can re-solder it back on. The Cap on the board can go bad an leak and take out a trace.
Sometimes you can just replace the cap.

No it does not but even if it did it would not make the speedometer jump.

 

Some guys buy two or three clusters at a salvage yard so that maybe one of the PSOM is a good one.

Note the replacement PSOM will have the mileage on it and post it on the odometer that the truck had that you remove the PSOM from.

 

Wow.... Can't believe a vital part to this vehicles function is on the verge of extinction, especially without a replacement made by an aftermarket vendor.

I guess I will pull the cluster and remove the PSOM. If I take it to work I may be able to locate it's problem and hopefully fix it..

How does this react with a manual trans? Would (eventually) changing over to a stick delete the re-occurrence of this issue?

 

In an Auto transmission the computer does the gear changing and regulates the oil pressure with information from the PSOM and the TPS plus a few other inputs.

I am not sure that a stick even has a computer. Both type of truck transmission do have a glow plug relay.

 

Well thanks for all the help this far. One more question. I know guys build these trucks for offroading and piece together interiors, is there a possibility that someone knows how to build an "aftermarket" gauge cluster made up of stand alone gauges that would work in place of this horrible design??

I'm seeing a large supply/demand issue with this and find it hard to believe that someone hasn't found a remedy.

 

I have two Fords with that cluster and I kinda like it.
I think it was a great design. I wish they would have stayed with it.

 

My '97 F250 460 E40D occasionally shifts hard from 1st to 2nd... Seems to do it more often under light throttle, and occasionally under moderate throttle. Other times it shifts silky smooth... I find when driving around the city that turning the OD "OFF" seems to make the shifting better... Other wise it will wander through the gears sometimes...

Figurd it was normal, but now reading makes me wonder if something is up with mine too?

 

I agree it looks nice, but by "horrible design" I meant that when it fails it renders the vehicle undrivable and now that part is obsolete unless you want to search far and wide for a good one and still end up with someone else's odometer reading. Not bashing the design quality, just realizing the fact that if I want to fix this there's no "new" part available to do so.

So my question is, do you think that there is a way to rig up an aftermarket speedo so that the trans will still get the info from the VSS without the need of this circuit board that seems to be a lot of peoples problems?

I may be thinking too old school here, but if you can take a block and a trans and build a mud buggy or something of the like with everything functional how is it there is absolutely no way to bypass this circuit board?

I'm thinking on the fabrication side. The glow plug harness for my truck was discontinued also, so we had one built. Is there nothing like that for this?

 

The PSOM is a computer to convert the pulse from a pulse train to a different pulse train that the PCM computer can understand.
Note that the older transmission mounted generator produced the same output that the PSOM does.
But with the tone ring the PCM Computer and the Speed Control module can not understand it, so it needs a translator.
The PSOM also keeps track of the tire size, mileage and trip mileage.

There is a company in Florida I think it is that can repair your PSOM and send it back to you. This company has been talked about on several post on this site and they have also posted on this site.