What might cause rough 1st-2nd tranny shift other than low&intermediate servo gaskets

This is the second transmission. It only has about 29,000 miles on it. The first one just needed new low-intermediate servo gaskets, but after 4 mechanics told us the tranny would need to be replaced, we just drove it till the gears in the tranny broke. I didn't find out the real problem till it was too late. I wish I had checked this board then.

This "new" transmission started to slip between first and second gears very badly after about 8 months. It was so bad I couldn't even use first gear. When I came to a stop, I'd put it in second, then shift to drive when it was appropriate. I changed the low and intermediate servo gaskets and the problem got about 80% better, but did not go away. I can now take off from a stop in drive, and if I'm very easy on the gas, it usually shifts okay. I can also usually take off fast with no problem as long as I let up on the pedal just as it's about to make it's 1-2 shift. I checked for the 2 C shaped clips on the piston and they were in tact. I have also tried replacing the o-rings and gaskets a second time this week since Ford would only sell me them in packs of 3 and I had the extra's. Does anyone know if there's anything else that might cause this other than a bad transmission?

When they replaced your trans did they use Mercon V fluid?? Did Ford put it in or did a trans shop do it??? Also did they give you a warranty?? If a trans shop did it they may have put a universal fluid in it. On the Ford Windstars that use mercon V this can cause a problem so I hear...Other things to check is the Trans range sensor AKA neutral safety switch. But would not think that would cause a slip issue.

The work was done buy a transmission shop. When I got the gaskets at the dealer I asked them what kind of fluid it took and they said Dexron-III Mercon, so thats what I put in. :banghead: I did the work on a hill so most of the old fluid came out. It took 4 quarts of fluid. I actually bought a filter cause I was gonna try changing that, so I'll try the mercon V. Would it be better to go with a synthetic fluid or just a good brand conventional type oil?

Let me back up a minute.. I assumed you had a later year model. your profile showed a 96. So if thats the case you do use Mercon not Mercon V. sorry for the error. Although I do hear Mercon will no longer be sold in a year or so. They say you can use Mercon V.. Mercon V is a synthetic. But for now you could change your fluid and with Mercon to see if that works..Since it is slipping. When mine was slipping a few years back I had the dealer to changed it and it worked fine after that.. I change mine every year now at the dealer.. Right now my trans pump is starting fail so a rebuild or replacement is soon in the works..I could opt for the pump replacement but with 101,000 + miles on it I sure it will be just a matter of time before it will go. Plus with the labor it would be more cost effective for me to wait for it to fail. Do you have the AXOD trans??
Also if you do the mercon change not sure if the dextron III mercon is the best way to go. Might just try to fine Mercon only if you can. I have to go to the dealer to get Mercon V...

Well I finally changed the fluid and filter. There was what looked to me like alot of very very fine metal powder around the magnet. There was a film of it on the tranny itself. I cleaned it as best as I could and flushed it with 16 quarts of mercon V as described on this forum. I have to say the problem definitley improved, but it certainly isn't fixed. For the first few minutes of driving, the car shifted perfectly. Then It started to act up. I can't really control it anymore by letting up on the gas, but it doesn't do it anywhere near as hard as it did. Also, now if I accelerate real hard from a stop so it shifts later, it shifts into second just fine.

I'm also experiencing a few new symptoms since the new filter. I live at the bottom of a hill and if I climb this hill before the van gets hot, when I get to the top and let off the gas for the traffic light, the tranny disengages, usually till I give it some gas again. This problem goes away after about 10 minutes of driving. This also occasionally happens if I make a turn fast or stop hard although not very often. Occasionally, when I slow down enough for it to shift back into first, I can actually feel it downshift. I do have an extra quart of fluid in there to keep the tranny from sucking up air.

Now I'm assuming that I've already done all I can do to fix this tranny and the damage is done, although I welcome any other ideas anyone might have. Is there an additive of some sort some of you might recommend? I've read in other posts about something I think was called lube guard red, or something to that effect, but I have only seen it recommended for shutter at cruising speed and I don't have that problem at all. Thanks for taking the time to read this and I'm sorry it ended up being so long.

Take a look at the pictures that the link in my signature takes you to.
I have step by step pictures that show the transmission fluid and filter change process.
The gasket on the neck of the transmission filter has a tendancy to be very stubborn about staying stuck in the transmission.
I posted detailed pictures that show this.
If the gasket from the old filter is stuck up in there....the new filter will NOT be correctly seated, and it is very likely that air will be sucked up at that point.

Mobil 1 is a quality fluid that is now Mercon V rated.
As I mention in the General Windstar Information post, FORD issued a TSB last year that supercedes all former TSB's about NOT using Mercon V in our older windstars.
Mercon V is NOW a qualified fluid for our Mercon transmissions.
Mobil 1 is a easy to find, synthetic ATF.

Take a look at the pictures that the link in my signature takes you to.
I have step by step pictures that show the transmission fluid and filter change process.
The gasket on the neck of the transmission filter has a tendancy to be very stubborn about staying stuck in the transmission.
I posted detailed pictures that show this.
If the gasket from the old filter is stuck up in there....the new filter will NOT be correctly seated, and it is very likely that air will be sucked up at that point.Thanks for the reply wiswind. I did look through your photos before I did the work. They have actually been a big help to me several times while repairing this van.

When I changed the filter the gasket was stuck as you said. I carefully pulled it out with a needle nose pliers. It came out pretty easily. I also took extra care to make sure the new filter was seated correctly and all the way in.

Mobil 1 is a quality fluid that is now Mercon V rated.
As I mention in the General Windstar Information post, FORD issued a TSB last year that supercedes all former TSB's about NOT using Mercon V in our older windstars.
Mercon V is NOW a qualified fluid for our Mercon transmissions.
Mobil 1 is a easy to find, synthetic ATF.The fluid I used was Mercon V, but it wasn't Mobil 1. It was Pennzoil, but it said Mercon V on the bottle. It wasn't the one that said "Rated for vehicle previously serviced by mercon and mercon V". I shopped around till I found the actual Mercon V. It was about $5 a quart, as opposed to the $7 Mobil one. I figured if it fixed the transmission, I'd change the fluid and filter again when I did my next oil change with the Mobil 1 since there was all that metal powder in there. Unfortunately for me, it didn't fix it.

You expect some metal "powder" on the magnets. What you don't want to see is silvery (aluminum or stainless steel) bits lying around in the pan.

I would change the 1st - 2nd servo gaskets/seals again, but I would do the work myself. Make sure all the parts are there ... such as the retaining circlips. Sorry, I just don't trust anyone else to do it right. It's not a difficult job.

There are also some shift solenoids under the end cover that play a role. Again not that difficult ... a bit messy. Be sure to do as much external cleaning as you can before any disassembly.

BTW, I have always used Mobil 1 in my '99 Winnie ... just wish I had started earlier with the changes/flushes.

You expect some metal "powder" on the magnets. What you don't want to see is silvery (aluminum or stainless steel) bits lying around in the pan.

I would change the 1st - 2nd servo gaskets/seals again, but I would do the work myself. Make sure all the parts are there ... such as the retaining circlips. Sorry, I just don't trust anyone else to do it right. It's not a difficult job.There were no metal bits of any sort that I could find in the tranny. Just that powder everywhere. I actually did change the servo gaskets myself. The seals and gasket only came in packs of three so when the problem didn't go away, I replaced them a second time. The second time I went to Ford and got a print out with an exploded veiw of the parts and how they go together. All the circlips and parts were there. I suppose I can do it one more time since I have one more set of gaskets left. It was easy enough to do.
There are also some shift solenoids under the end cover that play a role. Again not that difficult ... a bit messy. Be sure to do as much external cleaning as you can before any disassembly.
That I didn't know. Where about is this cover located and what does it look like?


I know what you mean about not trusting mechanics. I was burned pretty badly quite a few times by them. Where I live, I've only ever been able to find one honest mechanic, and he wasn't a very good one, just honest. I actually haven't taken any of my cars to a mechanic in almost 10 years just for this reason. The van belonged to my father when the transmission went and it was him who had it changed, although in this van, there's no way I would have been able to do it.

There was powerdery film in mine...which is shown in the pictures.
This was after 1 year and is normal.

By disconnecting the line that comes back from the cooler when you change the fluid, you are checking the fluid flow through the cooler.
When a transmission fails, it can put a lot of junk into the cooler line, and clog the cooler.
This will cause the replacement transmission to overheat and fail.
So it is ALWAYS required that the cooler flow be verified when a transmission is replaced.
If a transmission fails in 29K miles, there is something wrong, and it should be covered under the waranty for the replacement job.
If the failure was caused by the cooler being clogged....and they did not verify the flow when the unit was replaced, then it is their fault.
FORD issued a TSB on this, which I mention in the "General Windstar Information" post.

Another thing to do is to verify the radiator cooling fan low speed operation.
With the vehicle at idle, turn the A/C ON, and check to see if the radiator fans are ON, and staying ON.
The A/C being ON and the vehicle not moving at a minimum speed WILL cause the fans to be commanded to be on at low speed and stay ON.
If they are not on, then there is a problem.
A common cause of this would be the low speed dropping resistor, which is mounted on the metal bumper, behind the passenger side headlight.
I have a picture or so that shows this posted.
This will have a impact on cooling the transmission.

I'm not sure exactly how fast the fluid should be flowing. When I was flushing it out it took about 20 seconds to fill each quart. I already checked for low speed fan operation and it seemed to be functioning fine. The fans do come on with the air conditioner and they stay on.

As far as the transmission being under warranty, there's no chance of that. I went back to the shop that replaced it when I got the van and it was gone. For all I know, they could've repaired my old transaxle, put it back in, and said they changed it.:disappoin

I'm gonna do as 12Ounce suggested and change those 1st-2nd servo gaskets one more time. I doubt that will help anything since I've already changed them twice, but I still have a set of seals left so I've got nothing to loose doing that. If anybody can tell me anything else I can check for while I'm under there, that would be great.

Lastly I just wanna thank you guys again for all the great idea's you've all given me. If it wasn't for all the great info I've been able to get from you good people, I wouldn't even have a vehicle to get around in. Your help is GREATLY appreciated! :)

A quart in 20 seconds at with the engine at idle is within the 30 seconds MAX time for 1/2 quart at IDLE with transaxle in Neutral.

It is sad that the shop that you had the work done at is gone, and unfortunately you most likely don't have a receipt that will give enough detail to enable you to trace the unit back to the rebuilder.

FORD TSB 98-22-1 is for harsh 1st to 2nd gear upshift.
They have you go through a diagnostic process, and mention that if it is only on the first shift of the day, that is is most likely due to air in the hydraulic system....and to not do a repair.

They mention a build date range of 9/96 to 11/5/97, good luck figuring that out on your rebuilt tranny though.....an issue with the intermediate clutch piston.......

They mention the Electronic Pressure Control, and to check this pressure using a "NGS" tester to compare the actual pressure at the test port to the pressure commanded by the PCM.....at idle with the transmission in O/D.
They say that it should be about 10 to 20 psi at idle, with the transmission in Over Drive.
This sounds like the instructions are beyond the driveway mechanic.

FOR too high of EPC
They say that it could be a stuck EPC solenoid or pressure fail safe valve being stuck in the valve body.

Also, for too high of EPC pressure, with NO DTC (fault code or CEL), the following could cause this.
Vehicle Speed Sensor (VSS)
Throttle Position Sensor (TPS)
Transmission Range Sensor (TRS, aka Neutral Safety Switch)
Turbine Shaft Speed sensor (TSS, side of transmission case)
Mass AirFlow sensor (MAF).

That would put our friend, TRS on the short list. for high EPC pressure.

If the EPC pressure is correct, then they say that any of these valves could be sticking.....
1-2 shift valve
Intermidiate clutch shuttle valve
Capacity modulator valve
Accumulator regulator valve
Pressure failsafe valve.

Don't ask me about these valves......just reading from the TSB.
One thing (cheap and easy) that you might try, as they mention that sticking valves can have to do with dirt, etc......is a product called "AutoRX"
I used this on my tranny this past late winter, before I changed the fluid....and I did seem to notice the shifting get better....and it was not bad at all to start with.
This is only available online....and is the only thing that I know of that is safe to use to clean the tranny.
http://www.auto-rx.com/

The Auto-RX for the engine oil is the SAME product, same bottle as the one used for the transmission.....they list them separately to give you the instructions for each application.
I would put a full bottle into the transmission, and drive for the specified time period.....then change the fluid and filter........all the fluid, not just a pan drop.
I would do that before replacing valves inside the transmission.

Now......for the intermediate clutch piston needing replaced.
Do not repair if the harsh shift is ONLY on the first shift of the day.
With LIGHT throttle, verify harsh 1-2 upshift ONLY....with normal 2-3 and 3-4 upshifts.
If ALL shifts are harsh......they say to look at what I list above and NOT the intermediate clutch piston.

Next.....try with a "heavier throttle".....aka harder accelleration.....If the 1-2 shift is now normal when it is harsh with very light accelleration, then they say to look into the intermediate clutch piston.
If the 1-2 upshift is still harsh under harder accelleration, they say that the problem will NOT be solved with a intermediate clucth piston.

So intermediate clutch piston is suspect ONLY if there is harsh 1-2 upshift.....with all other (2-3 and 3-4) upshifts normal.......and it ONLY happens under light accelleration......but NOT under hard accelleration.

WOW! Lots of great info. Actually all the other shifts are normal. Once your out of first the transmission shifts very well. If I hit the gas hard it shifts into 2nd perfectly. Lately I find myself taking off very fast just for that reason. Now the Intermediate Clutch Piston is the thing with the spring I removed to change the o-ring on right? Is it the spring that I would need to replace or the piston itself? I assume this is something I can only get at the stealership?

They mention replacing the intermediate clutch piston....which, I think, is pretty far into the unit.....like WAY deep into the transaxle.
This is well out of my knowledge area...and is best left to someone more experienced than I to offer advice.

[quote=BlueCaprice]WOW! Lots of great info. Actually all the other shifts are normal. Once your out of first the transmission shifts very well. If I hit the gas hard it shifts into 2nd perfectly. Lately I find myself taking off very fast just for that reason. Now the Intermediate Clutch Piston is the thing with the spring I removed to change the o-ring on right? Is it the spring that I would need to replace or the piston itself? I assume this is something I can only get at the stealership?[/quoteHas anything helped?Having exactly the same trouble except mine only shifts to 2nd well if you accelerate hard and let off before the first shift.All other times first shift is hard,lite or heavy acceleration.Works fine starting in 2nd also.

The "end cover" I wrote off is a vertical cover on the LH side of the engine compartment("rear" of tranny?). Aluminum (in my case) and about a foot-square ... several small bolts. Reusable gasket as I remember. The cover "covers" the main valve body. A number of small solenoids, thermal sensor, etc inside on top of valve body.

I'm no tranny expert either ... just been kinda lucky so far.

If you've already changed the seals on the 1st-2nd servo, I'll bet they're still good and don't need replacing.