03 Windstar transmission - slip/shudder

Hello everyone,
I have a 2003 Windstar, 105,000 miles. Recently I noticed a slight "jumpiness" at highway speeds. It seems to slip from high gear and then back in, resulting in a noticeable lag/pull feel with a bit of a shudder. It seems to do it more on hills. It's hard to describe other than that. It seems to shift fine from starting. I have tried turning the OD off and it still happens. I have not noticed the OD light flashing on/off.
Transmission fluid is reddish, does not smell burnt. I plan to do a flush (by the way, which hose do I remove/cut? Top or bottom??) and change the filter. To my knowledge it has not been done to date (yes I know, should have been every 40K). I got the van at 69,000.
I have done the TSB for the isolator bolts on this van thanks to all of you folks, so I really want to keep it going, however, a big bucks tranny overhaul or replacement is not what I really want to do at this point (like anyone does)
PLEASE HELP - THANK YOU!!

I just had the same problem with my 96 while I was 800 miles from home. I was sure something electronic was causing it to slip while in OD for a second or 2 then reingage. A fluid change by the cooler line flush method (in the motel parking lot) cured it. I have since driven it about 1200 miles with no problems.

Remove the lower cooler hose at the trans, leave the other end connected to the cooler. Place the hose from the cooler in a can and fire it up. I filled the trans 3 times and let it pump out till it started to pump alot of air each time. Then hooked the hose back up, filled and ran it then toped it off.

I did read someware that the cooler flow was reversed in the middle of a model year (do not know what year) so it may not be a bad idea to put a hose in the trans line also and put both hoses in the can. I got mine wrong the first time and it can make a mess.

Good luck

Thanks, I think definitely the first thing to try is that flush. I will drop the pan and clean it out and change the filter also.
I will post back with the results...
thanks again for your reply.

I have pictures posted in the pictures that the link in my signature takes you to that cover transmission fluid and filter change.
Keeping the fluid changed is a very important thing with modern automatic transmissions.
When my A/C is on, I will notice the engine RPMs bump up momentarily whenever the A/C compressor engages.
Way to find out if this is what is happening is to set the air controls to VENT, which will have the A/C OFF.
If the problem goes away, then it is just the normal compensation for the compressor load.

Hello everyone,

Well I dropped the transmission pan and replaced the filter, cleaned the magnet and replaced about 7 quarts of Mercon V fluid.
The filter was black, the magnet had a fair accumulation of fine particles, but there were no major metallic pieces. It drives noticeably better! I installed a drain plug and plan to drain the fluid out of the pan this week and top it up again, which should give me about 9 quarts of new fluid in there..
Still noticed the occasional shifting slip or “bump” especially when going up OR down hills, twice the engine actually geared down while going down a hill with the cruise control on, as evidenced by the tach jumping up.
I have confirmed that this does not have to do with the AC kicking on.
Based on what I read here, I am considering replacing the Speed Sensor. At $30 from Rock Auto it’s not an expensive shot in the dark.
But, I have not seen the OD light flashing and I don’t want to change it if there is no chance that it’s at fault.
Can anyone confirm any particular behavior associated with the speed sensor? Light flashing?
Again, 2003 winny with 3.8, 106K miles

Thanks to you all for your help.

i had the same problem with my 95 i just changed the fluid and filter and added a bottle of lubegard red. that did the trick also make sure you use mercon v fluid. there is a lot of useful info on their website www.lubegard.com

Thanks all for your responses. I drained the fluid and topped it up with 7 quts of new Mercon V. Just took in on a 7 hour drive and noticed no problems at all. Think I dodged a bullet on this one, I plan to change the filter and fluid the same way every 30K from now on. 200K here we come!
As an aside, while I was at it I suctioned about 8 ounces from the power steering reservoir and added new Merc V, did that twice and it's MUCH quieter. Think I will do that each oil change and over 3 or 4 times that should give it a complete change.

thanks again for the responses. this forum is a lifesaver.

As for your your power steering read owners manual. I have 2001 and it calls for Mercon ATF in power steering not Mercon V.. IN POWER STEERING.. Just don't think Mercon V will hurt but it could eat up the seals.. I use Dextron/Mercon in my power steering the dealer said thats fine...In fact they sale Dextron /Mercon Motorcraft brand.. LOL I thought Dextron was GM owned... But they got it on the bottle I have right now..

With FORD discontinuing the Mercon License, I would expect that the Mercon V is what you would now use.
My AlldataDIY subscription only covers my '96, which lists "Type F" ATF for the power steering, so a TSB about Mercon to Mercon V for power steering is likely to not show up in my list.

Dexron is a GM Specification, Mercon / Mercon V are FORD specifications.
Most ATF manufactures meet several OEM specifications.
As the end user, we only care about the 1 specification that covers our vehicle.

I am thinking that Mobil 1 ATF, which now is Mercon V (and states that it is also for where Mercon is specified...which matches the FORD TSB), would be great for both the Tranny and the Power steering.
That will give you another brand, in addition to the Motorcraft, in case you cannot find 1, you should be able to find the other.

I checked the owners manual and it says MERCON ATF. From all my web searching it seems that Merc V satisfies all requirements in applications where Mercon is specified. I think I will leave it as it is.

I have pictures posted in the pictures that the link in my signature takes you to that cover transmission fluid and filter change.
Keeping the fluid changed is a very important thing with modern automatic transmissions.
When my A/C is on, I will notice the engine RPMs bump up momentarily whenever the A/C compressor engages.
Way to find out if this is what is happening is to set the air controls to VENT, which will have the A/C OFF.
If the problem goes away, then it is just the normal compensation for the compressor load.

I came across this today regarding transmission failure:
Ford AX4S Transmission Problems 1995-2000 Windstars

"An early symptom is often a noticeable change in engine rpm of 200 to 300 rpm while driving at highways speeds in overdrive. This is often due to the transmission losing lockup pressure."

http://www.aa1car.com/library/transmission_ford_ax4s.htm

I saw that in the first long drive after we bought our 96WS. Could have been the AC since it was on for this drive. But I think I have seen it once or twice when the AC was not on, driving the WS home after getting the transmission flushed. I don't drive it often and then generally not at cruising speeds. But I think I need to take a test drive and watch for this.

My 2000WS manual also states the use of mercon ATF for the power steering but I went ahead and flush the system out with Mobil1 ATF and everything is running great, So you should be fine with what you've installed in you P/S system. Windstars are notorious for scorching the fluids and I suspect that's what's happening with the tranny as well, that's why I'm going to flush mine with Mobil1 and install a cooler.