Need advice - tanny shudder not fixed by fluid change

I have a 2000 SEL 3.8 with 80,000 miles... Recently we've noticed a shudder at around 40MPH, usually when I'm in the gas, going up hill for instance. It doesn't seem to be happening with a gear shift, but between shifts. The TAC also seems to blip up 100-200 RPM when it happens. From everything I've read on this board that looks and sounds like a Torque Converter slip?

After reading that some people saw the problem go away after a tranny fluid change, I had the transmission flushed (Mecron V) on Thursday and it actually seems to be worse after the flush.

I need your advice - Where do I go from here? I saw someone had success with an additive - should I try that? Should I take it back to the shop and have them drop the pan, clean it out and change the filter (another $200)?

Any ideas what my prognosis is if I can't get this corrected? is it only a matter of time before I'm into a $2000+ tranny replace?

try adding a bottle of lubegard red to the tranny this may help your problem. good luck!!!

if I take it to a tranny shop will they be able to get a look at the insides and tell me anything meaningful, or will they just be guessing based on what it's doing? should I even bother or should I try an additive first?

Sometimes the TPS, or MLP can cause strange tranny problems.

i would try the lubegard first, this may fix the problem, the windstar as with a lot of other ford vehicles are prone to torque converter shudder when trying to lockup in overdrive. you can go to their website and it will explain how it works. www.lubegard.com

Just scheduled a free tranny diagnostic at a local shop for Thursday... also picked up some lubeguard red, but I'm holding off on putting it in until after the appointment so that the tranny guys can get a good look at it without the problem being masked by the lubeguard.

Another note that I found interesting - the problem seems to go away competely (or get far less noticable) when the A/C is turned off. I drove around for 2 hours yesterday looking for the lubeguard, and purposefully left the A/C off and couldn't get the shudder to occur, even when I TRIED to re-create the circumstances that are causing it.

does that suggest it's not the tranny at all? or could an electrical problem be CAUSING a tranny slip, somehow, maybe by sapping power from the hydraulics or something?

Just scheduled a free tranny diagnostic at a local shop for Thursday... also picked up some lubeguard red, but I'm holding off on putting it in until after the appointment so that the tranny guys can get a good look at it without the problem being masked by the lubeguard.

Another note that I found interesting - the problem seems to go away competely (or get far less noticable) when the A/C is turned off. I drove around for 2 hours yesterday looking for the lubeguard, and purposefully left the A/C off and couldn't get the shudder to occur, even when I TRIED to re-create the circumstances that are causing it.

does that suggest it's not the tranny at all? or could an electrical problem be CAUSING a tranny slip, somehow, maybe by sapping power from the hydraulics or something?


Have you checked your Battery or Alt out. Seems like you may be on your way to a bad batt.. Worth looking at first.. Also a bad coil will do this as well but you should get a flashing CEL after it gets worse.. That could make a bump or shutter issue not slipping trans..

You will feel a bit of a "bump" through the powertrain when the A/C compressor kicks in.
It is also normal....particularly on hills for the engine to rev up just a bit when the A/C compressor kicks in......I don't know if it is shifting down a gear momentarily or just unlocking the torque converter momentarily.
The point of this "rev up" the PCM commands this to handle the sudden increase in engine load and prevent the engine from "bogging" down.
The A/C compressor is still engaged when the engine drops down in speed, but the engine is giving the extra power needed to handle the load.

I Have A 98, Which Has A Lot Of Miles On It, So That Could Be Most Of The Problem, But It Will Switch On The Overdrive Light On The Shift Knob, And It Will Start Flashing, Then It Seems To Shift Out Of Overdrive, And The Tach Jumps About 1 Grand Or So, Like Its Dropping Into 3rd Gear. If You Pull Over And Shut It Off Then Restart, It Resets It I Believe And Then It Runs Fine, Until You Start Up A Hill And Put Any Considerable Pressure Back On It Again, It Will Also Shift Real Hard If You Come To A Stop While The Light Is Flashing.

Thanks for the ideas / comments, guys. I did replace the battery about a year ago - so I'm guessing that's not the problem. But I will take a closer look (or ask the AAMCO guys to) at the ignition coil and the alternator.

To be more precise about what's occuring - it's like a series of bumps in rapid succession, similar to what it feels like going over some really nasty ruble strips.Maybe 5 or 10 of them. When it occurs engine revs a bit (100-200 RPM). It seems to happen most frequently at low RPM (around 1500) going up hill, with the A/C on. The bumps actually seem more harsh after changing the fluid, but I guess that could be my imagination or a coincidence.

We'll see what the AAMCO guys say tomorrow... if they don't seem to have a clear fix for it, I'll dump the LubeGuard Red in there as suggested and see if that helps. Winter is nearly here, so the lack of A/C and the LubeGuard might buy me some time.

Went to the tranny shop this morning. There are no codes showing in the tranny computer, a quick visual instection of the ignition coil didn't reveal anything, and after a 45 minute drive the shop indicated that they DID notice the problem, but it was so slight that they couldn't guess at it's origin (engine, electrical or tranny).

They recommended I just drive it until it gets worse or the CEL comes on.

So I just dumped a bottle of LubGuard Red in there - cause I don't know what else to do at this point. We'll see if that helps.

I'm between a rock and a hard place - I'm trying to decide if it's time to get rid of this vehicle (before the tranny fails). But to make that decision I'd like to know what's causing the problem, obviously. The problem isn't bad enough to diagnose at this point, but if I wait until it is, it might be so bad I kill my re-sale value and have no choice but to do a tranny replace and keep it for another couple years. So, I guess we'll see if the LubeGuard helps, and buys me some time. If it doesn't help, I'll have to decide to either a) get out of this vehicle (potentially prematurely), or b)let it ride and hope it's not a serious tranny problem that's only going to get worse.

Yea the bump thing sound like my problem and only happen on and off. Although mine leaks after about ten miles but has not leaked anymore even though I went over ten miles the other day with no problem. They told me my trans pump is going. So I am going to wait until it go's.. Good luck...

well - the lubeguard doesn't seem to have made any difference at all, unfortunately. I'm gonna try a bottle of injector cleaner next (just cause it's cheap and it couldn't hurt).

From reading all the threads that talk about a shudder - my problem could be anything from the tranny slipping to the fuel injectors being clogged to the ignition coil having cracks to the transmission pump failing - only to name a few. At this point the problem isn't significant enough to chase with hundreds of dollars of repairs / parts replacements that may or may not fix it. So I'm going to try the less expensive remedy's unless or until it gets worse. Now I have to decide if I want to risk it getting worse and costing lots to fix or if it's time to start shopping for a new minivan!

If its your primary car then by all means look for a new one. I have 2 minivans my 2001 Windstar is my just drive it to work van. I am really a sports car fan but for some reason I just like this van. So when my trans does go out I just may replace it and keep it. IF the day comes and the deal is right I may get my RX 8 I have been wanting..And say so long to my Windstar..

it is my wife's primary vehicle to taxi our 3 little ones around in, and we're going to replace it at some point in the next 12 months anyway. it's served us well for almost 8 years now. I was hoping to get another winter out of it, but at the moment I'm leaning toward selling it / trading it in before the problem gets any worse.

having said that, tho, my wife reports today that she hasn't felt the sudder in a couple days now. I had put a bottle of injector cleaner in the tank this weekend just because it was worth a shot. I obviously don't know at this point if the injector cleaner made a difference, if it's running better because of the cooler weather, or if maybe the oil companies have dialed back the ethenol content for the fall / winter??

Anyone know if the fuel mixes would have changed this early in the year?

If the cooler weather has made a difference, does that suggest a possible cause to anyone?

i had to drive mine a couple of days after adding the lubegard approximately 100 miles before i felt the difference, it's been a couple of months now and have not had anymore problems out of it, hope you have the same results as i did from the lubegard

You will feel a bit of a "bump" through the powertrain when the A/C compressor kicks in.
It is also normal....particularly on hills for the engine to rev up just a bit when the A/C compressor kicks in......I don't know if it is shifting down a gear momentarily or just unlocking the torque converter momentarily.
The point of this "rev up" the PCM commands this to handle the sudden increase in engine load and prevent the engine from "bogging" down.
The A/C compressor is still engaged when the engine drops down in speed, but the engine is giving the extra power needed to handle the load.

After getting the tranny fluid replaced, and then going back again to get the filter replaced I went out for a 20 mile drive. Did not feel the shudder at cruising in that time, did not see the 200 rpm blip I had seen with the AC on.
But, when I put the air control to Vent, when the AC should not be running I began to see the 200 rpm blip again. Turned off the vent and the blip disappeared. What's up with that? Is the AC running when it should not be or something?

New to the board ... this thread sounds like I wrote it!! I have an 02' Windstar and am experiencing the exact same issues mentioned here. Shutters between 40-60mph, seems to be around the shift point, is worse when a/c is running. I would add that I experience the same issue when cruising between 70-80mph as well.

I've done the plugs, wires, fuel filter, fuel pump relay, DPFE, checked EGR, checked PCM for water leakage (TSB) etc. Can't seem to get close to a fix. Scheduled an appointment at the dealer for Tuesday, but am thinking of cancelling after reading this post and hearing that the tranny shop couldn't find any issue big enough to diagnose. I have feared that all along, that I would pay $100 service fee to have them say they can't duplicate the problem enough to start diagnosing.

I noticed you post on the lubeguard was a few days ago ... any updates on how that worked out?

New to the board ... this thread sounds like I wrote it!! I have an 02' Windstar and am experiencing the exact same issues mentioned here. Shutters between 40-60mph, seems to be around the shift point, is worse when a/c is running. I would add that I experience the same issue when cruising between 70-80mph as well.

I've done the plugs, wires, fuel filter, fuel pump relay, DPFE, checked EGR, checked PCM for water leakage (TSB) etc. Can't seem to get close to a fix. Scheduled an appointment at the dealer for Tuesday, but am thinking of cancelling after reading this post and hearing that the tranny shop couldn't find any issue big enough to diagnose. I have feared that all along, that I would pay $100 service fee to have them say they can't duplicate the problem enough to start diagnosing.

I noticed you post on the lubeguard was a few days ago ... any updates on how that worked out?

it's worked out just fine for me, changed the fluid and filter, used mercon v fluid and the lubegard red. took a couple of days but since then no more shudder.

I must say the fluid replacement (Mercon V) and filter replacement seems to have taken care of the tranny shudder while cruising. Drove 300 miles this weekend and did not notice it at all. I'm feeling a little better about the transmission is this recently acquried WS now.