Ford Auto Transmission Problem

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Hey guys..................

I Got a wired transmission problem going on with a 1994 Fored Escort. When you start the car, every transmission position wants to makes the car drive forward - there is no reverse or neutral. But when you turn the engine off, you can find neutral and the car can be pushed that way.

So I'm thinking this is an electronic issue and not a mechanical one. My code reader gave me a code of 639 - which refers to an issue with the Transmission Speed Sensor.

Has anyone ever dealt with this problem or know much about this code and whether or not it can cause this situation???

Thanks for any help.

posted by  Mark whiz

wondering if you found anything? That is a really bizarre problem. I talked to a dealership and they mentioned an MLP (manual lever position) sensor that may be almost seems as if it tries to move forward even in park until the parking pawl catches. I feel a slight lurch forward when I put it in park until it hits the stop. I just picked this car up at auction and I am hoping it will not be a complete loss. Oh, if anyone is able to help, details on the car are 92 1.9 4 door auto trans with approx 130Kmi. I tried removing the linkage and clicking the gears in by hand with the same result (thought possibly linkage adjustment, but no luck). Thanks.


posted by  paxgaea

well, so far there's been no joy on a fix. I went ahead and replaced the TSS sensor ($200 at Ford) and it didn't do a dang thing.

Upon doing some research on that system - I'm almost convinced that the trouble lies in the solenoids located in the shifting body inside the transmission. I'm gonna do a good check thru the dash for any possible bad connections or broken/frayed/cut wiring - and if nothing turns up there, the whole beast goes to Ford to figure it out. :ohcrap:

posted by  Mark whiz

I had to move this car the other day, so I got in, started it up and pulled around the block and went to pull up into my driveway (which is a slight incline) and the tranny immediately started slipping and would not move the car at all. So, just for kicks, I threw it in reverse and it actually drove backwards for a 100 feet or so. I was in awe, so I thought I would throw it back in drive and maybe that would work also. It didn't. All it would do is slip. So I threw it back into reverse and then the same thing started happening in reverse, it wouldn't go anywhere. So, now I was stuck in the middle of the road, so a friend of mine helped me push it up into the driveway. Then I checked the fluid on the tranny (the first time I have done this on this car) and it was blacker than the motor oil. I had never seen anything that looked that bad. So, I am doing to drain out the fluid and throw some new stuff in there and find out what the tranny does then. Have you by any chance tried replacing your fluid to see if it changes anything? I really didn't think by the way the car was acting that it could be a fluid problem, but after seeing the way that fluid looked I wouldn't be surprised now. I will follow up after I change out the fluid to let you know what happened.


posted by  paxgaea

Fluid issues can definitely cause shifting problems - no doubt of that. Unfortunately the fluid in mine is fine. It was the first thing I checked when the trouble started and it is the right color and at the right level - and I had changed it out about a year ago and it was normal then too.

I REALLY have to wonder why yours got so dark. Has the crankcase oil level been dropping any??? I would hate to think that a rear engine seal let go and filled the tranny with oil.

What you describe, about how sometimes Reverse works and drive doesn't and then reverse quits and drive starts working is exactly what mine is doing. When pulling up into your driveway, did you try dropping the gearshift into Low? When Reverse works on mine, you have to start out in low or it just slips horribly - like the thing is stuck in 3rd gear, which is exactly what I think it is doing. And that is what is making me think it's one of the 2 shift solenoids in the shifting body.

posted by  Mark whiz

Check the connector to the sensor. High engine temps can cause it to fail. The sensor tells the ECU what the transaxle input speed is for selecting the electronic shift.

posted by  Wally

have noticed on escorts, approx 85-110k miles, the trans will start to act up. depending on how often the fluid is replaced. also fords trans did not have proper lube on one of the shafts so this will cause a problem in the future. taurus,aerostar 80-130k trans go bad. i have had 5 escorts 87-94. most trans have gone out by 160k. and the rear seal of the crank will leak onto the ground and not go into the the trans. there is a torque converter in between. trans is not hard to change on the escort. about 3-4 hrs r & r with a floor jack. caution on taking the half shaft out, don't crack the housing!

posted by  doug wong

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