1998 Ford Windstar 1998 Ford Windstar P1780; Erratic Trans

Tiny
SCHRIMPIEMAN
  • MEMBER
  • 1998 FORD WINDSTAR
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 140,000 MILES
Thx in advance for any help! Symptom: Lets say we just started the vehicle for the day ("cold" start ~70 Deg F. Weather), drove a few residential streets, then merged onto an expressway for continuous 55+MPH driving for ~10 miles. Then exit and continue on residential streets. Come to a complete stop for a red-light intersection. Light turns green and accellerate in normal fashion. The vehicle will start off in 1st gear like everything is normal, but at random times it will not shift up to 2nd nor 3rd gear. The tranny does not slip (eg. The engine has plenty power and accelleration is brisk, but back off on the throttle and you're coasting it's as if in neutral). Now that the symptom is active, slow down to ~3 MPH, place the gearshift in 1st gear, and accellerate again. Feels normal, back off the throttle, and the tranny drags the vehicle to a slower speed (which is normal because gearshift is in 1st gear). Anyway, put gearshift in "D" again, accellerate. Back off the throttle after reaching 20-25MPH, coast for ~500 feet, then you can feel the clutches "engage". It shifts into the higher gears and you drive like nothing ever happened. Come to a stop again and it's 50-50 chance the symptom will re-occur while at operating temp. The car runs flawless during warm-up period.
A few months previous to this, when coming to a complete stop with gearshift in "D", press on the accellerator and the engine revs with plenty of power, but it feels like you're in Neutral. The only way to get power to the wheels is to shut the engine off, then restart in P or N, and then shift to D. Then drive away as if all is normal. This happened only about 5 times, but may be related to the non-shift-up problem.
I've added an aux trans fluid cooler (in front of the radiator) thinking cooler fluid would benefit. No better. Fluid is still clear-pink, at proper level. Tranny was rebuilt about a year ago; gave 15,000 trouble-free miles. I don't see the correlation between the Ford-Specific P1780 Trans Control Switch being out of Self-Test Range (presumably the OD button at tip of gearshift) and the shifting problem. Other P1780's refer to a Park/Neutral switch, but more so for the Asian market.
Finally, I'm aware that Ford changed the tranny fluid spec during mid-year-production in 1998 from Mercon to Mercon-V. I'm to the understanding that the two are not compatable and cannot determine if the trans shop (a year ago) installed the appropriate rebuild kit due to the mid-year 1998 production change, nor if they even added the correct fluid. Who knows if they mismatched the early-production-year rebuild kit with Mercon-V or vise-versa? The invoice does not say and I didn't ask the questions when the tranny was rebuilt. .I trusted them. Hah.
So, I guess my overall question is: Any advice on how I should proceed? I'm to the understanding that there's a solenoid pack/assembly near the top of the tranny which, if replaced, might resolve the problem.
Sorry for the lengthy text, but I wanted to include all relevant info in hopes for an accurate response. Thx.
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Wednesday, December 17th, 2008 AT 7:43 PM

5 Replies

Tiny
JAMES W.
  • MEMBER
First of all, I'm going to "scold" you. Don't ever, ever, appologize for giving too much information. If more people did, it would make our job a lot easier. We are hundreds or thousands of miles apart, so we can't hear the vehicle run or test drive it, so the only thing we have to go on is what you tell us. Your description of the symtoms really helps narrow the problem down. Ironically, I drive a '98 Windstar with 100K and luckily, I've had no tranny problems though they are noted for weak transmissions. I have to believe the possible difference in trans fluids is not an issue or you would have had problems before 15K miles. And being it's intermitent, it has to be electrical not a "hard" failure. I don't find a code #1780 in my code list. Are you sure this is correct?
ALL OF A SUDDEN, my research access has failed. I'm going to have to try a different access route which requires me to logoff and reboot. I'll try to get back to you yet tonight, if not, in the morning. In the interum, would you verify the P code for me. I'll be back.
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Wednesday, December 17th, 2008 AT 10:32 PM
Tiny
SCHRIMPIEMAN
  • MEMBER
It's on various places on the Web. You can do a google search, or:
http://www.2carpros.com/trouble_codes/obd2
and scroll down near the bottom. Various other sites will define P1780 the same way.

Unfortunately, the P1780 tends to focus attention to the OD control switch, which isn't even an operational factor until the transmission reaches 4th gear. There shouldn't be any affect to 1st gear.
Also, there is no difference with the OD selector button being either "on" or "off", the little LED light at the end of the gearshift lever. Either way, the tranny acts up as described.

My next step will be to clear the DTC's (Diagnostic Trouble Codes) and get the vehicle through its OBD Drive cycle in efforts to replicate the symptom and get the PCM to set the code again.

OK: Detailed explanation(s) accepted and encouraged. Gotch-Ya. Thumbs Up.
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Wednesday, December 17th, 2008 AT 11:42 PM
Tiny
JAMES W.
  • MEMBER
Well, I'm back. My internet has been down all day. It sounds like your 2nd gear solenoid is hanging up. Have toy tried running the van up past where it would normally shift into 3rd and see if it bypasses 2nd, but goes into 3rd? If you were to plug in a scan unit and observe it while driving, the pcm would narrow it down for you. BUT, being an intermitent problem, it could take days to show up.
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Thursday, December 18th, 2008 AT 10:10 PM
Tiny
SCHRIMPIEMAN
  • MEMBER
Yes, I've accellerated the vehicle to about 4000 RPM in 1st gear (gearshift selector in "D" position), let off the throttle and see what would happen. As mentioned before, it seems to then clunk into gear after about 500 feet and continues driving normally. Until the 50-50 chance it'll happen again at the next stoplight.

Your hunch that it is bypassing 2nd gear may be accurate. I honestly didn't even think about this until you mentioned it.

My expertise rests in engine rebuilding / chassis, and now I'm focusing my attention more to diagnostics & drivability concerns. Luckily, I own a PC-based OBDII diagnostic scanner. I'll need to see how many PID's I can access on the transaxle side of things.
Most of the time, I monitor engine performance; the transmission tab (on the menu) has been one of those "Well, I'll get to it later some day" options. Now is the time I start exploring the PID's under the Transmission Diagnostics Menu, eh?

I have PID event recording options, so I'll select the appropriate PID's and monitor them as you suggested.
Thank you very much for your input thus far. I'll keep monitoring the situation and provide feedback and possible repair details when I get the symptom sorted out.
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Thursday, December 18th, 2008 AT 11:53 PM
Tiny
SCHRIMPIEMAN
  • MEMBER
It's been nearly 2 months since opening this topic; just wanted to follow up w/ some results.

I installed an aftermarket transmission oil cooler instead of going with more expensive repair means such as new solenoids, etc; seems like symptoms have gone away for now. I'm not sure if it's coincident with the cooler weather we're having here in South Florida, or if the original problem was just intermittent, or whatever.

Fact remains that I installed the trans fluid cooler in line with the factory installation. Clarification: Hot trans fluid enters the factory radiator inlet, out the radiator. And then it runs through a few feet of flexible transmission hose into the aftermarket oil cooler installed in front of the A/C condenser. Finally, the fluid runs back into the tranny through another flexible hose.

We haven't had any really hot days here in S. Florida so I guess we need to wait for springtime to arrive before I can determine if temperature has any relevance to issue.

We'll see.
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Tuesday, February 10th, 2009 AT 7:32 PM

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