Transmission / speed sensor

Tiny
OLSSTABBY
  • MEMBER
  • 2001 LINCOLN LS
  • 150,000 MILES
Dear Sirs,

I have a 2001 LS with a 3.9l and a 5R55N trans. I have no R or 5th. (Slipping) There is no shifting in D, just slipping. I get all gears but R and 5 in manual operation, although there is a flair between 2 and 3. The computer speed sensor reads 0 MPH no matter the speed although the speedo is correct. I use an AutoEnginuity Proline Scanner. I have checked all of the transmission speed sensors for ohms and they all passed. I checked the output from each sensor while the trans was running. They all provided feedback consistent with rotational speed as measured by the O-scope. All waveforms were sinusoidal and variable depending on speed. The computer read and displayed the rotational speed of the TSS. It displayed 0 MPH for all RPMs on the VSS. There was no way of reading the ISS. How would I verify a malfunctioning Computer input? Did I already verify it with the O-scope? I don't even get an error for the loss of signal with it. Research tell me there is a problem from day one from the factory settings for the vehicle regarding a warm-engine hard starting condition. This is the most problematic car I've ever owned. The car has everything but reliability. Don't ever buy one! Unless you too want to be in the poor-house.
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have the same problem?
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No
Monday, May 13th, 2013 AT 12:06 AM

3 Replies

Tiny
ASEMASTER6371
  • EXPERT
Reverse and 5th share a clutch internally. It sounds like you have an internal failure.

Roy
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Monday, May 13th, 2013 AT 2:41 AM
Tiny
OLSSTABBY
  • MEMBER
Thanks Roy ASEMaster6371. I do think the same. I rebuilt the trans with similar thoughts. I found out fast that quick decisions are usually a poor choice. I had similar problems with my Chevy truck. (No 3 or 4th). Rebuilt it, problem solved. This time I found clutches in good condition. So I do have to look into broken springs in the valve body or worse a worn out valve body. I do have that problem with the speed sensor though that will cause no shifts in D. Does the fact that the computer doesn't register vehicle speed indicate a bad input since I know there is a signal? (Measured with an O-scope)

Thanks,
Mike
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Monday, May 13th, 2013 AT 1:19 PM
Tiny
ASEMASTER6371
  • EXPERT
Check all piston seals and the pistons for cracking.

Roy
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Monday, May 13th, 2013 AT 6:26 PM

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