Speedo and shifting issues
Thread Starter
Junior Member
Joined: Jul 2016
Posts: 5
Likes: 0
Speedo and shifting issues
Hey Yall been lurking for a while found a lot of great info on this site and Im pretty sure I narrowed down the issue but wanted to confirm before throwing any more parts at it. 92 F150 5.0 A/T 2wd I got it free it was sitting out on a farm forever they said it had transmission issues. Drove it around and found that it was shifting hard wouldn't downshift properly when accelerating and wouldn't go back to 1st gear at a stop without manually shifting then the rear ABS light came on. Add in the speedo issues of not registering speed from a stop and jumping around once you started moving pointed to a VSS. I replaced it today and sure enough now im getting accurate speed from about 0-20mph the transmission goes back into 1st gear on its own now but still shifts kinda harsh and has a situational delay in downshifting but rear ABS light is off so a great start/improvement for a $30 part.
Now the issue is over about 20mph the needle just swings by about 10-15mph back and forth so i cant tell what my actual speed is. Based on everything ive been reading im thinking its a PSOM issue. Any way to test for sure before I try ordering one? Is it possible the diff fluid just needs to be changed would it even make a difference? Just asking cause it looked a little grey to me didnt know if contamination could throw off these sensors but no metal shavings or anything on the stock 160k VSS so im guessing rear is in ok shape.
EDIT*****
Anyone know if this could also be bad grounds? I have a random starting issue as well that im thinking is possibly bad grounds but havent had a chance to work my way around the truck checking them all. Is there a main cab ground I should look at anywhere?
Now the issue is over about 20mph the needle just swings by about 10-15mph back and forth so i cant tell what my actual speed is. Based on everything ive been reading im thinking its a PSOM issue. Any way to test for sure before I try ordering one? Is it possible the diff fluid just needs to be changed would it even make a difference? Just asking cause it looked a little grey to me didnt know if contamination could throw off these sensors but no metal shavings or anything on the stock 160k VSS so im guessing rear is in ok shape.
EDIT*****
Anyone know if this could also be bad grounds? I have a random starting issue as well that im thinking is possibly bad grounds but havent had a chance to work my way around the truck checking them all. Is there a main cab ground I should look at anywhere?
Last edited by FbodyLT1; Apr 10, 2020 at 04:30 PM.
Member
Joined: Jan 2018
Posts: 11,256
Likes: 1,770
From: Memphis, TN, Earth, Milky Way
Put ALL the truck's details into your signature, as this caption explains:
(phone app link)
I hope you kept the original ABS sensor because the new one probably isn't working right. Most don't - generally, you'd need to find an original in a JY to get a good signal to the PSOM. But the sensor isn't usually the problem. Read these captions:
(phone app link)
(phone app link)
(phone app link)
(phone app link)
"Bad grounds" is an overused catchphrase. What exactly are these starting problems? There are several grounding points on the truck, and they're equally-important.
(phone app link)
(phone app link)
(phone app link)
(phone app link)
Follow the links in this caption:
(phone app link)
(phone app link)
I hope you kept the original ABS sensor because the new one probably isn't working right. Most don't - generally, you'd need to find an original in a JY to get a good signal to the PSOM. But the sensor isn't usually the problem. Read these captions:
(phone app link)
(phone app link)
(phone app link)
(phone app link)
"Bad grounds" is an overused catchphrase. What exactly are these starting problems? There are several grounding points on the truck, and they're equally-important.
(phone app link)
(phone app link)
(phone app link)
(phone app link)
Follow the links in this caption:
(phone app link)