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1996 F-250, 205K miles. The transmission has worked fine most of the time but lately there is an intermittent problem of not shifting out of 1st or sometimes 2nd gear. After moving the lever from 1st through to D it might clear up, or maybe after restarting. In the past I have had a P0500 code for the VSS and have replaced the sensor twice and also the pigtail wiring.
The problem is still occurring but not setting any codes now. I don’t know what else it could be without a trouble code.
Are there any other sensors that could cause this, or any other troubleshooting ideas y’all may have?
Also, is there any way to test a VSS to see if it is good?
On her rig the fluid level is full. And it is bright red. No engine lights. Trans temp is usially 160° at the highest. And the absolute highest I’ve ever seen was 195° last summer. Not really sure what is up.
If the VSS signal isn't getting to the PCM it won't upshift. Find out why it's setting the P0500 code and you'll find the problem.
It could be a bad VSS (vehicle speed sensor,) or the wiring to the VSS, or a bad PSOM (Programmable Speedometer/Odometer Module.) The PSOM is located behind the instrument cluster.
What’s up with these intermittent shift problems? Replace parts and check wiring, truck runs fine for a couple of months and then won’t shift and throws a VSS code. It’s difficult to fix a problem that only happens when it wants to.
Are any of you guys still on an original trans? Seals wear internally causing shifting issues as do soiled valve bodies.
I have a 328k never opened trans in a car (aside from fluid changes), it acts weird at times and even more when cold...trans was built late 1989 for 1990. That is 30 years back. Nothing rubber will last that long and be dependable.
Mark told you guys what to inspect. If you have done that and confirmed all of that, sounds like a worn out unit to me due to simply worn out seals.
I’ve attempted to fix by replacing the sensor twice and the pigtail plug also. Wire appears to be undamaged.
Still fails to shift and throws a code randomly and intermittently. I not sure where to go next with it.