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Discussion Starter #1
hey guys( 1992 FORD BRONCO 351W ) i have searched and found much info but still a bit confused. my transmission has gone crazy!

first it began to shift extemly hard.
i changed the rear abs sensor and the abs light went off

second the spedometer began to jump about 5mph like from 45 TO 50 or if your going like 60 mph it will jump to 55? i cant find the speed sensor anywhere on the transmission. the one they showed me on the adv computer looks like a oil pressure sensor. where is it located on the transmission?

third the transmission is confused? sometimes at 30mph it shifts into overdrive then other times it wont shift into od at 65! also when it shifts to od at 30mph it wont shift out until almost full throttle? the only time the check engine light comes on is when the transmission shifts back and forth trying to decide what gear to go into!

i tried to find a picture of the speed module in the dash and where this dang speed sensor in the transmission is? ANY HELP WILL BE GREATLY APPRECIATED!!!!

thx in advance
travis
 

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the speed sensor (VSS) is on the differential not in the transmission.

By the way if the VSS is bad the shifts are very violent or crazy as you put it.
 

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Satyr of the Midwest
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You might want to pop your differential cover and see if the exciter ring mounted to the carrier has damaged teeth, or if there are metal bits in the oil. If the VSS is all right, and you can test the lines going all the way up to the PSOM and those are all right, I'd say you might be left with a bad PSOM, but I'd have to read up a little more in my Ford Service CD to be sure.
 

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Discussion Starter #4
hey guys thanks so much for your help! i took off the rear cover and there is no metal in there and i just replaced the sensor. where is this module you speak of? thx in advance travis
 

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hey guys thanks so much for your help! i took off the rear cover and there is no metal in there and i just replaced the sensor. where is this module you speak of? thx in advance travis
did you take a GOOD look at the whole tone ring and inspect all the teeth on it?
 

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Discussion Starter #7
i am gonna tear the rear cover off again tomorrow and check the ring again. i sure hope thats all thats wrong with it..... thx again guys!!
 

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Discussion Starter #9
ok guys im still trying to find a rear abs tone ring. as soon as i get it if thats not it could have my mlps sensor gone bad and be causing this? i do drive through water often with the truck...
 

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Discussion Starter #10
thanks i will do!
 

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ok guys im still trying to find a rear abs tone ring. as soon as i get it if thats not it could have my mlps sensor gone bad and be causing this? i do drive through water often with the truck...
MLPS wouldn't cause the speedo problem...


Your tone ring is INSIDE the rear differential. You have to take the cover off the differential to see it.
 

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Hate to hi jack the thread, but I just put an 85 rearend in my truck. And it doesn't have a VSS/ABS sensor on it. What kinda issues can I expect fron mot having it. My truck is an 89 with a 4.9.
 

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Discussion Starter #13
well i took all the plugs off and checked them. the only code that came up was 654. thats the transmission not in park code right? i am assuming this it why i have to pull the shifter way up to start sometimes..... is that the mlps sensor bad? only code was 654 thanks in advance. yes i have am still looking for a tone ring if anyone knows of someone who has one to get rid of please let me know!
 

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Discussion Starter #14
well when i replaced the abs sensor the light went off and the speedo does not seem to jump at all. the tone ting has some very small imperfections on a couple teeth but none missing not even close.
 

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Hate to hi jack the thread, but I just put an 85 rearend in my truck. And it doesn't have a VSS/ABS sensor on it. What kinda issues can I expect fron mot having it. My truck is an 89 with a 4.9.
Don't hi-jack the thread then. :twak

Your RABS won't work. That's all.

well i took all the plugs off and checked them. the only code that came up was 654. thats the transmission not in park code right? i am assuming this it why i have to pull the shifter way up to start sometimes..... is that the mlps sensor bad? only code was 654 thanks in advance. yes i have am still looking for a tone ring if anyone knows of someone who has one to get rid of please let me know!
well when i replaced the abs sensor the light went off and the speedo does not seem to jump at all. the tone ting has some very small imperfections on a couple teeth but none missing not even close.
So wait... does your speedo still jump around?

Your MLPS might just need to be adjusted.
 

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Discussion Starter #16
no my speedo does not jump. i replaced the rear abs sensor and now its fine. but there were some teeth nicked so i was going to replace it. so how is the mlps adjusted? i never moved it?
 

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Discussion Starter #17
it being the rear tone ring
 

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Sounds like the MLPS could just need adjusting since you need to shove the lever up into drive to start it. From what i have read on here, to adjust the MLPS you have to put the truck in park and then align the lines on the trans and the MLPS. Hope it works!
 

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You might want to pop your differential cover and see if the exciter ring mounted to the carrier has damaged teeth, or if there are metal bits in the oil. If the VSS is all right, and you can test the lines going all the way up to the PSOM and those are all right, I'd say you might be left with a bad PSOM, but I'd have to read up a little more in my Ford Service CD to be sure.
Is the PSOM the actual speed-o assy? Also how exactly would you test the lines from the VSS to the PSOM? is it a visual inspection or checking for voltage or continuity? I have the same problem as slydogge but the VSS/ABS didnt fix mine. I am going to check the exciter ring tomorrow. Only difference is mine is a '95.
 

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Discussion Starter #20
i am going to check mine tomorrow and report back. i just dont see how it could get out of adjustment?
 
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