96 Strange transmission behaviour

shankster · #1 12-17-2006, 08:30 PM

I have a 96 Windstar with the 3.8, 160,000 miles. I had a rebuilt tranny installed at 140,000 miles exactly 2 years ago. I got the tranny from Phoenix Hard Parts off an ebay auction. It's not exactly the same as my original tranny - it fit and it works but not sure what it came off.

Anyway, I just changed the filter. After the filter change (and 5Q new fluid) the pan was leaking badly (mainly because I got a 96 Windstar gasket from Ford that wasn't a good fit). After 20 miles I pulled the pan again, sealed everything up, another new 5Q Mercon and I thought I was good to go.

Everything was working fine till I was climbing a steep hill and kicked down to pass. The tranny shifted down, engine raced up to 5k+ and power was not being transmitted to the wheels - I eased off, it shifted up and worked normally till I tried the kickdown again - same thing. After that the tranny wouldn't go into overdrive and the OD light started flashing on the shift lever. I stopped, shut everything off and started up again - no change, still wouldn't go into OD. I endured this for 100 more miles till I got where I was going. After the car sat overnight and I drove back home it was shifting into OD just fine - relaxing drive till I (almost home) started climbing the other side of that steep hill and tried the kickdown again. Exactly the same thing happened and it wouldn't go into OD again. When I got home I disconnected and reconnected the battery and went for a drive (the van maybe sat 10 minutes). Everything worked perfectly. I tried kickdown on a flat stretch, then a slight grade - no problems.

So what's going on? I'm driving the family from CO to CA in 5 days - should I be worried? Is this a sensor issue or an internal valve blockage issue or something else? Should I have the tranny flushed? Add some tranny conditioning stuff? I'm thinking it had something to do with the new fluid I added loosening up some internal junk. I recon if it happens on the long trip I'll at least be able to stop and disconnect the battery to get OD back but it's still something that's got me worried - don't want to be stuck on some mountain pass in a blizzard with a fried tranny. Also the idea of being on the interstate for 1000 miles on the old tired motor at 75 mph and 4000rpm makes me real nervous. Any suggestions would be much appreciated.

wiswind · #2 12-17-2006, 10:01 PM

A tranny shop or dealership will be able to read the transmission codes and tell you what the electronics see as the problem.
The flashing O/D light is indicating that the electronics sees a problem, and has stored a code.

Transmission fluid should be changed at least every 30K miles.
The pan drop is getting only roughtly 1/2 of the fluid.
Total capacity on the '96 windstar transmission is 12.25 quarts.
Having nice fresh and clean fluid in there is super important.

As this tranny is "not exactly", I do not know what the total capacity is.
However, there is a TSB that states that the cooler line should be flushed, and that the flow through it should be verified.
Reason, when the old transmission fails, it often puts a bunch of junk into the fluid.....which has been known to clog the cooler (which is inside the radiator).
The clogged cooler causes the replacement transmission to over heat and fail.

Another TSB was just released this past July, that supersedes former TSBs on transmission fluid.
FORD now says that the transmissions that call for Mercon rated fluid can now use Mercon or Mercon V.
That TSB also stated, as in the past TSB's, not to put any additives into the fluid.

A super common failure with the transmission is the Transmission Range Sensor (TRS), also called "Neutral Safety Switch".
The TRS sits on top of the transmission, and is what the gear select lever connects to.

shankster · #3 12-17-2006, 11:32 PM

Quote:

Originally Posted by wiswind

A tranny shop or dealership will be able to read the transmission codes and tell you what the electronics see as the problem.
The flashing O/D light is indicating that the electronics sees a problem, and has stored a code.

Thanks Wiswind. Can I just take it to Autozone for code reading like I usually do or is there something special about getting tranny codes? There is no tranny shop in my small town and the Ford dealer is the most worthless, untrustworthy business in town.

Quote:

Originally Posted by wiswind

Transmission fluid should be changed at least every 30K miles.
The pan drop is getting only roughtly 1/2 of the fluid.
Total capacity on the '96 windstar transmission is 12.25 quarts.
Having nice fresh and clean fluid in there is super important.

This will be 20K and as I dropped the pan twice I recon I maybe got a 2/3 fluid change. Hopefully that will be good enough till next time. Before I did this service the tranny was working perfectly - only after the filter/fluid change did it start acting up.

Quote:

Originally Posted by wiswind

As this tranny is "not exactly", I do not know what the total capacity is.
However, there is a TSB that states that the cooler line should be flushed, and that the flow through it should be verified.
Reason, when the old transmission fails, it often puts a bunch of junk into the fluid.....which has been known to clog the cooler (which is inside the radiator).
The clogged cooler causes the replacement transmission to over heat and fail..

Hmmm! hopefully I don't have that problem - the rebuilt unit has done fine for 20K of pretty hard use and I wouldn't think it would have survived without cooling.

Quote:

Originally Posted by wiswind

A super common failure with the transmission is the Transmission Range Sensor (TRS), also called "Neutral Safety Switch".
The TRS sits on top of the transmission, and is what the gear select lever connects to.

I replaced that early in the life of the first tranny - behaviour is similar but not quite the same. It occurred to me that might be an issue but could there be any relationship between that and my filter change? Whatever the problem is hopefully the code read will pick it up.

LeSabre97mint · #4 12-18-2006, 07:51 PM

Hello

I had a flashing OD light (the "check tranny light") on my 95. I don't remember the code off hand, but a new Vehical Speed Sensor (VSS) fixed it up just nice. I posted the fix on this forum. Do a search for VSS or flashing OD light.

Regards

Dan

wiswind · #5 12-19-2006, 08:57 PM

Someone correct me if I am wrong....but my understanding is that the transmission codes cannot be read with a generic OBDII code reader.....it will require a more advanced code reader......which costs much more money.
A good automotive repair shop should have one.

LeSabre97mint · #6 12-20-2006, 06:40 PM

Wiswind

I was able to read a speed sensor errors with my PC based code reader. I believe that is a trannie code.???

Regards

Dan

LeSabre97mint · #7 12-20-2006, 06:40 PM

Wiswind

I was able to read a speed sensor errors with my PC based code reader. I believe that is a trannie code.???

Regards

Dan

wiswind · #8 12-21-2006, 02:35 PM

It makes sense.....many of the transmission items are used by the PCM to determine engine controls.
It sounds like it is always worth getting the codes read for free.
However, the reader that they use at Autozone and other auto part stores are generic code readers, such as many of us use.
They can do a much more involved reading with the code readers that they use at the dealership and major repair facilities.....which can read manufacturer specific codes, and can also run test routines.

From reading the forums, it seams that we get a LOT of coverage with the "P" codes with the generic OBDII code readers, but there are more codes and test routines that can be of help in specific situations.......but I would add.....in the hands of someone who knows how to use them....

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