Trans problems I think?

[xpldingtaco]

So after about 2 weeks of scouring the web for an answer I feel as though I’m ultimately left with asking you guys outright. I have a 96 xlt, 4.0 auto with 4wd. I’ve seen where it is a very hated transmission and I’m beginning to understand that.

Let me preface this with; this car was given to me free. It was my high school first car, and my mom just gave it back to me. It for a while had an issue with the speedometer intermittently working. Sometimes it would just come to life while driving but almost always just read 0. I, via the information in this forum, figured it was the VSS that has the plastic white gear on it that bolts into the transmission directly. I bought a replacement from amazon (link: https://www.amazon.com/dp/B009AA9IN6?tag=seriouexplor-20) and while it didn’t fix my problem completely, it did make the Speedo work for like the first 20ish minutes of driving and then it would drop right back to 0. I said to hell with it I’ll buy an aftermarket gps speedometer to put on the dash and be good. Now a new problem arises and my fear is it’s either related to the sensor I changed, or it’s coincidental and I’m going to be rebuilding a transmission. It was driving fine, I went up a hill, (25mph posted) came back down doing about 30, there is a speed increase at the bottom of the hill as the road levels back out, I tried to accelerate to 35 as the new posted was 30, and my rpm’s went up while my speed rapidly went down. I let off the gas, as the car slowed down it rather angrily slammed back into a lower gear, I assume first or second, and would allow me to drive up to 20mph before doing the same rpm increase while speed decreased with the transmission either not engaged or not transferring any power to the wheels. My O/D light works, didn’t and hasn’t flashed yet, neither has the transmission light on the dash. Checked fluid, I was low, replaced it with mercon V, tried to take it out again in hopes maybe it was just temperamental, and same thing is happening. No acceleration past 20mph, no lights on in the dash except for a check engine light now. I haven’t limped it to the closest auto parts store to check the code as I live on a pretty busy main road with a 35mph speed limit and not very close to an auto part store. Am I in for a rebuild, or did I get a bad VSS? Anyone have any further at home testing recommendations? Thank you in advance and sorry for the book of a post.

 

[Mbrooks420]

What happens if you put it in manual 2? Does it move?

 

[xpldingtaco]

What happens if you put it in manual 2? Does it move?

I will attempt that next. I put it in 1 and it went when I was testing it after adding trans fluid. Didn’t attempt 2 though

 

[410Fortune]

Your speedometer drive gear is probably worn out
There is plastic gear that drives the little vss gear. It would work for a few minute and then stop again because the drive gear gets worn out down the middle and cannot make contact

That will help with the speedometer issue and hopefully some of your transmission issues are related to the pcm/ truck not knowing you are moving

 

[xpldingtaco]

Your speedometer drive gear is probably worn out
There is plastic gear that drives the little white vss gear you installed. It would work for a few minute and then stop again because the drive gear gets worn out down the middle and cannot make contact

That will help with the speedometer issue and hopefully some of your transmission issues are related to the pcm/ truck not knowing you are moving

You’re talking about the actual white toothed gear behind the speedometer in the cluster correct? Not the worm gear notorious for being brittle and failing to track miles?

 

[xpldingtaco]

So after about 2 weeks of scouring the web for an answer I feel as though I’m ultimately left with asking you guys outright. I have a 96 xlt, 4.0 auto with 4wd. I’ve seen where it is a very hated transmission and I’m beginning to understand that.

Let me preface this with; this car was given to me free. It was my high school first car, and my mom just gave it back to me. It for a while had an issue with the speedometer intermittently working. Sometimes it would just come to life while driving but almost always just read 0. I, via the information in this forum, figured it was the VSS that has the plastic white gear on it that bolts into the transmission directly. I bought a replacement from amazon (link: Amazon product ASIN B009AA9IN6) and while it didn’t fix my problem completely, it did make the Speedo work for like the first 20ish minutes of driving and then it would drop right back to 0. I said to hell with it I’ll buy an aftermarket gps speedometer to put on the dash and be good. Now a new problem arises and my fear is it’s either related to the sensor I changed, or it’s coincidental and I’m going to be rebuilding a transmission. It was driving fine, I went up a hill, (25mph posted) came back down doing about 30, there is a speed increase at the bottom of the hill as the road levels back out, I tried to accelerate to 35 as the new posted was 30, and my rpm’s went up while my speed rapidly went down. I let off the gas, as the car slowed down it rather angrily slammed back into a lower gear, I assume first or second, and would allow me to drive up to 20mph before doing the same rpm increase while speed decreased with the transmission either not engaged or not transferring any power to the wheels. My O/D light works, didn’t and hasn’t flashed yet, neither has the transmission light on the dash. Checked fluid, I was low, replaced it with mercon V, tried to take it out again in hopes maybe it was just temperamental, and same thing is happening. No acceleration past 20mph, no lights on in the dash except for a check engine light now. I haven’t limped it to the closest auto parts store to check the code as I live on a pretty busy main road with a 35mph speed limit and not very close to an auto part store. Am I in for a rebuild, or did I get a bad VSS? Anyone have any further at home testing recommendations? Thank you in advance and sorry for the book of a post.

A coworker said that his late 90’s mustang did similar things and it was his pcm, is this also something I should be investigating?

 

[410Fortune]

No I am talking about the drive gear in your transfer case
That drives the vss sensor
They wear down and quit making contact. So a new vss may work for a few
Minutes until the work gear quits turning it again

 

[xpldingtaco]

What happens if you put it in manual 2? Does it move?

It does move. However now that I've shifted it through the gears with the door open, I can hear that it is shifting SUPER rough. What I can only describe as a crunching sound is heard, loudest when going R->N->D or vice versa. Trans fluid, while it does slightly leak, is still good. Pulled the check engine light and came back with P0401 'Exhaust gas recirculation flow insufficient' and while that raises a new question, I don't think it relates to my transmission/acceleration issue. Sorry for the delay in getting back to you, this is just my backup car and I wasn't able to do much diagnosing last weekend.

 

[xpldingtaco]

No I am talking about the drive gear in your transfer case
That drives the vss sensor
They wear down and quit making contact. So a new vss may work for a few
Minutes until the work gear quits turning it again

Is there somewhere online that you can find that shows specifically how to check/replace this? The only thing I could find was a guy saying he spent a few hours pulling everything apart to change it, but then finding out he actually didn't need to disassemble everything.

 

[410Fortune]

Pull the 10 or 11mm nut that holds your vss sensor into the transfer case
Remove vss
Put finger in the hole and feel the drive gear, it is likely worn down in the middle. You can use your phone camera to take a pic as well

Access to the drive gear is not terrible but first let’s confirm it’s worn out first