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Discussion Starter #1
Well I have a 94 Bronco XLT 351W with a E4OD tranny stock height with 32" tires.(I searched and pulled codes) Here's my problem, my truck every once in a while shifts real hard, I pulled codes and I got a 452 : Insufficient input from Vehicle Speed Sensor to PCM so I cleaned the plug for the vss and bought a new one, replaced the diff. oil (no visible metal shavings), and even inspected the tone ring gear and still had the same problem. So I read that the MLPS could cause the problem without throwing a code, I replaced it with the newer design along with the plug and aligned it properly. Same problem persisted along with the same code after being cleared. My next thought was that the wires may be broken or damaged so i followed the wires and inspected them and could find no fault in them, once again I cleaned the connector for the vss and coated it in dielectric grease, and cleared the codes. It didn't act up for a while, but my hopes were shattered this weekend when i took a trip to Nashville. I was merrily driving along when my cruise control ceased to function, I pulled over to the rest stop and it was shifting hard and sporadically like it didn't know what gear it was supposed to be in. I let it sit for about 15 minutes or so and hit the highway again, it shifted perfectly and cruise once again was operational. I almost forgot to mention that even though I'm getting a 452 code my speedometer is still functioning, no jumping, quivering, or any indication that the psom isn't getting feedback from the vss. It did the same thing on the way home so I pulled codes and once again got a 452. I'm also getting a 32 code from counting the airbag light but i doubt this would effect the transmission. I rechecked everything that I checked before found no fault. :banghead I need some help to know where to look next, right now I feel like :whiteflag but I wont give up cause I love my truck too much.
 

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well, have you checked fluid and all. i live in north alabama also, i think your best bet is a transmission shop, what part of north alabama do you live u could tell you a couple good places, if your interested.

Taylor
 

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What does your seedometer doing when this happing? Does it bounce around or quit working all together? You could have a PSOM issue (Programble speedometer odemeter module) and need to replace the insturment cluster. The VSS signal goes from the rear speed senser through the PSOM to the PCM. You really need to follow a pinpoint test to be accurate because you don't want to make a 500$ mistake. as far as the 32 airbag code you may need a new clock spring. hope this helps.
 

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well, have you checked fluid and all. i live in north alabama also, i think your best bet is a transmission shop, what part of north alabama do you live u could tell you a couple good places, if your interested.

Taylor
Okay, in his post, he clearly stated that he's got an electronics problem... fluid level, or lack of it, doesn't cause at all what he's describing. Read the post before throwing random suggestions out. His best bet is some diagnosis and help from here, because a transmission shop is going to tell him that he needs to rebuild his transmission. They all do that.

What does your seedometer doing when this happing? Does it bounce around or quit working all together? You could have a PSOM issue (Programble speedometer odemeter module) and need to replace the insturment cluster. The VSS signal goes from the rear speed senser through the PSOM to the PCM.
He said that his PSOM was fine display wise, but you're right, the output from the PSOM goes to the VSS, and that's where the problem may lie.

Though not quite right, the VSS information starts at the ABS sensor in the rear axle on a 92+, goes to the ABS module first, and then to the PSOM.

There is a test in Steve83's PSOM thread, so search for that, it may reveal something... otherwise, the PSOM can be replaced alone, and you can even get a lower mileage one and run the miles up to your current mileage with an easy trick that Steve83 can also help you out on... he's usually got a few for sale if you need one.
 

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Discussion Starter #6
thanks

Well I'll do some reading on steve83's post and see if it shed some light on my problem, yes my fluid is at the correct level and has been changed recently just to clear that question, and I live in the Decatur area but i wont go to any of the tranny shops around here because they'll only do what Bronco4Life said. Maybe I can do some more testing and prodding around somewhere between school and the fire department, it just had to pick a busy time to act up like everything else does :doh0715:
 
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