The Diesel Stop banner

Transmission popping out of gear/being indecisive

1K views 11 replies 2 participants last post by  Ball 
#1 ·
Hi. I just bought a 1995 E350 Ambulance (7.3 Powerstroke) and the transmission is acting very odd. The previous owner thought this issue was fixed by replacing the speed sensor on the rear diff, but apparently that was a false positive.

I discovered the problem after climbing a steep hill. Before even climbing (on flat ground) the transmission seemed a little indecisive about which gear it wanted but I didn't think much of it since I'm not familiar with Fords and it only happened for a half second. After the hill climb and back on flat road it shifted into a low gear (2?) as the engine revs were very high and I wasn't going anywhere. I turned around and went back to town (since I didn't want to get stuck in the middle of nowhere) and it stayed in 4th gear going downhill. I hit the OD off switch and it switched to 3rd just fine, then near the bottom of the hill it started being indecisive again.

I'm sorry if that's as clear as mud, but that's the sum total of my experience with the vehicle. The transmission seems strong when it decides which gear to use, but popping out of gear makes the van unusable. It's currently parked until I can get some guidance from one of you Ford gurus or the local mechanic get some free time to check it out (earliest Monday...and I was hoping to be out of here by now).

Any ideas? :)
 
See less See more
#2 ·
Oh, and I drove it the night before and in the morning without issue. It only came back in the afternoon. Temps were only around 95°

Tranny fluid appears to be the right level (the dipstick is that weird plastic white pill thing so I don't know the exact level but it got wet after drying it).
 
#3 ·
One of the most common causes of this problem is a failing Transmission Range Sensor (TRS.) It's also called a Manual Lever Position Sensor (MLPS) or Neutral Safety Switch (NSS.) It is on the driver's side of the transmission. It is the part with the wiring harness. Replace it.
 
#5 ·
They work by adding a resistor each time you move a position away from park. As they age internal resistance builds and it will sometimes get high enough to read one or two positions further down than you really are. That causes a downshift.
 
#10 ·
Yes there is. I don't have it, and you don't need it. Unless you can read the values going down the road, and have the sensor disconnected from the computer, you're not going to learn anything. It will test out perfectly fine sitting still. Replace the sensor.
 
#11 ·
Welp, I changed the neutral safety switch and the camshaft position sensor to no avail. Despite 106° temps I'm confident I changed them correctly.

Nothing changed for the better or worse (other than thinning the wallet and cooking my brain).

Looks like it's about time to abandon the vehicle in the hands of a specialist who will likely have possession for weeks before his schedule frees up.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top