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· Registered
237 Posts
Discussion Starter · #1 ·
I have a 1995 powerstroke 7.3.
One morning I noticed my speedo on dash was bouncing all over the place and then my OD lite came on and then I lost everything, no speedo and tranny wouldnt shift right.
So I stopped for a minute and started to go slowly to just try and get it home when my odometer came back and speedo started to work again but it still bounced.
I read about the VSS ontop of the rear diff and I replaced it.
My speedo would work but when it got over 45-50 mph and higher, it would bounce again, but my abs light and OD light do not come on.
I looked at the wire harness going to and away from the VSS to make sure wiring was ok and didnt see anything wrong, so I looked at the ground wires up front near the battery and radiator and all is good.
So I let it sit for awhile until I had more time to look at it, it is my wifes truck by the way.
Now that Iam driving it for now, I noticed the speedo will bounce all the time again.
Removed the VSS and made sure it was clean and it is, I stuck my finget in the hole to feel the ring gear and feel nothing wrong, like a broken tooth or something.
When I turn the ign. key on the abs light comes on for a second and goes off like it should and when Im driving it, the abs light doesnt come on nor my OD light, but the tranny shifts irractically at times.
I went back to the auto parts store to see if there is another sensor I may be over looking and they sold me a sensor that is thier book,

but I cannot find it anywheres on the tranny or transfer case, so I think it is a wrong part.
Any ideas ??
Could it still be a VSS even tho I replaced ??

· Registered
713 Posts
not sure what the thing in the pic is.......but another thing that goes bad is the PSOM, the speedometer module in the dash cluster, causes erratic and hard shifts and the speedo wobble, if that is it you need to fix it before it takes out the tranny.....mine went.....went thru all the VSS stuff etc (had a vss issue prior)... it would down shift at 70mph..absolutly brutal!! Sorry if that is the culprit they are not cheap.

· Registered
237 Posts
Discussion Starter · #3 · (Edited)
I took it into a shop I have been too before,
I told them what it is doing and and what I had changed and checked myself.
I even told them that I had gone to ford dealership and they said it most likely was the module on the cluster assembly.
At first they thought they could order me a whole new cluster assembly with the module, they just needed my vin#.
It would cost me $600.00 parts and labor so I told them to order it and let me know when it would be in, but of course, they found out, you cant get it anymore, ford says it is obsolete.
The shop was going to take mine apart and send it in and get one rebuilt for $500.00, so I gave them the go ahead.
3 days latere it was done, so my wife went to get it right when they were closing.
She was told that the owner drove it and all was fine, the speedo was not bouncing at all anymore, but when she went to drive it away, it was shifting so hard in and out of gear so hard, she thought the tranny was bad, and the owners son , who worked on it, said that something was wrong so he hooked up his meter to it and pulled a vss code.
He told her to go ahead and limp it home and have me change out the vss again and remove the battery cables for 20 min. to reset everything.
I got home , it was dark, and I took it for a drive,
no turn signals,
half the dash lights wouldnt work,
OD light flashing,
banging in and out of gears,
speedo would bounce after going 30mph,
This was on Friday night, so Monday I took it back and told the owner, he didnt care, almost like, too bad, and I started to get very mad until his son came in and took care of it.
He spent 2 days cheking over wiring and pcm and all
To make it short now, they spent a week on it checking everything only to find that module was still bad, changed it out again and now it is ok.
What a pain..

· Registered
33 Posts
I'm not sure if my problem is related but here's what my speedo is doing, and it seems like I really ever noticed it until I had the smf conversion. Whenever I shift and accelerate from like 1000 till 1600 the clutch makes a loud noise and my speedo jumps around a couple miles per hour. It's not really that big of a deal to me and my speedo is pretty dead on according to street meters on the freeway at steady speeds, but I was just wondering if this is at all normal? Keep in mind that I did have the 3.55s swapped in from the 4.10s somewhere in the equation here. Any input would be nice!

· Premium Member
381 Posts
i had that problem on a 93 f350 duel rear wheel and the sensor in the rear end was destroyed because the left Carrier bearing for the ring gear was bad don't know if that is your problem, but pop the sensor out and take a look only take 10 min.
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