Transmission shudders, clunks on 3 - 4 upshift.

[riverguy]

Just started on a road trip: 1999 Town Car, 130K miles, always serviced transmission on schedule. At light throttle, the 3-4 upshift is smooth. Pulling up a bit of a hill, the shift happens with a short shudder that sounds and feels like driving over a rumble strip in the pavement. Then when slowing down and it shifts back down to 3rd,(by itself), there's a bit of a "clunk." Happened only occasionally, then after the last 300 miles on the road, it's doing it all the time now.

Is this something that an adjustment is likely to fix? Maybe a bad vacuum actuator? ANYTHING but a a transmission o'haul?

First major issue ever with this car!

 

[Town]

I don't think you have a vacuum problem since your trans is all electronic, no real adjustments from the outside. I would find a good trans shop (difficult while on a trip) and get a professional diagnosis. Sounds like the valve body is playing up and can be tested and fixed or replaced. The valve body is not always replaced in a transmission overhaul because it can be easily fixed later through the transmission pan.

Has the transmission been serviced in 133k miles, how long ago? My 2007 model scheduled trans oil change is 250,000 kilometers (155,000 miles) but I had the trans flushed with a new filter at 60,000 kilometers (37,000 miles).

Good luck.

 

[riverguy]

Transmission clunks, shudders on 3-4 upshift

I don't think you have a vacuum problem since your trans is all electronic, no real adjustments from the outside. I would find a good trans shop (difficult while on a trip) and get a professional diagnosis. Sounds like the valve body is playing up and can be tested and fixed or replaced. The valve body is not always replaced in a transmission overhaul because it can be easily fixed later through the transmission pan.

Has the transmission been serviced in 133k miles, how long ago? My 2007 model scheduled trans oil change is 250,000 kilometers (155,000 miles) but I had the trans flushed with a new filter at 60,000 kilometers (37,000 miles).

Good luck.

I bought the car two years ago from the original owner with 98K miles on it. It's now at 130K. I have all the service records since new. The last transmission service was at 77K miles and there was one more at 42K miles. All the service was done at the S.F. dealer that sold the car new.

I can minimize the shudder/clunk thing by doing my best to anticipate upshifts on the highway and using a very light throttle at the time, resulting in a smooth shift. The downshift when slowing down from highway speed is a bit more difficult. And in any driving below 50 mph on curvy-hilly terrain, I just lock out the OD.

I think we'll make it back home alright, and I'll schedule a trip to a local transmission shop there that has a good reputation. Thanks for the suggestions!

Add-on: I've been doing some more research on this and found several complaints of identical symptoms, particularly the "like driving on pavement rumble strips) and the diagnoses were a torque converter clutch malfunction. What are your thoughts on this as a possibility?

 

[Town]

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Add-on: I've been doing some more research on this and found several complaints of identical symptoms, particularly the "like driving on pavement rumble strips) and the diagnoses were a torque converter clutch malfunction. What are your thoughts on this as a possibility?

Yes I think a malfunctioning torque converter clutch may cause a vibration but limiting the effects to the 3 to 4 shift would be unusual. The clutch must be released in order to shift so I would expect the problem to occur more often and at lower speed when the torque multiplication is greater.

I will check the 1999 service manual and see if there is some diagnostic help for you.

Good luck.

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[riverguy]

Yes I think a malfunctioning torque converter clutch may cause a vibration but limiting the effects to the 3 to 4 shift would be unusual. The clutch must be released in order to shift so I would expect the problem to occur more often and at lower speed when the torque multiplication is greater.

I will check the 1999 service manual and see if there is some diagnostic help for you.

Good luck.

I see what you mean about a clutch malfunction would show up on all shifts. Not happening. The rest of the shifts, even on heavy throttle (which I do rarely), are smooth. I just started also noticing a shudder (again like the rumble-strips thing) when pulling up a gentle slope at like 50 mph just when the transmission would normally try to shift down from OD. At that point, there's just the shudder and the transmission stays in OD, but if I don't arrest the situation, it will continue to try shifting down. When that happens now I just lock it out until back on level ground.

 

[Town]

The 1999 service manual is all about tests that a Ford mechanic can carry out using the test equipment and the taps on the trans to get pressures. The only DIY info related to torque converter clutch vibration is to replace the trans fluid if brown and burnt or otherwise dirty fluid i.e. not a clear red colour. It should be Mercon V now that Mercon is discontinued. I think you have 53,000 miles on your current trans oil so it is time for a change. How does it look? Since you have a torque converter drain plug you can replace most of the oil yourself. The procedure is fairly easy and I can get it for you.

There are a lot of valves and solenoids in the valve body that need to be checked for shifting issues. I would let an expert diagnose your problem using the proper equipment.

Good luck.

 

[boatme99]

I think Town is correct. The fluid and filter might need to be changed again.
My first 94 Town Car did the same thing on the test drive! Luckily, I had experience with the 93 Town Car and an honest trans shop before. Simple fluid and filter change on both vehicles straightened it right up. It also got me a heck of a deal on the car.
BTW, although not necessarily recommended, I always change a filter whenever any fluid is changed. A lot of shops will just pump the fluid out through the dipstick tube and not drop the pan and call it a "service". Maybe that's what the last service was.

Oh yes, when the trans pan is dropped the the first time, you'll see a little ball of plastic with a spru on it, mine were yellow, it's a plug that was used in manfucaturing, I believe to plug the bottom of the dipstick tube, it just floats around in the pan until you remove it. If you see this at your next service, you'll know that the pan has never been dropped so filter has never been changed.

If the fluid is disclored or burned after a short period, then yes, you probably have other problems.

 

[boatme99]

Found a pic of the dingus...

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[riverguy]

OK, thanks for all the help! I have an appointment at a good transmission shop near home and I'll have them do a complete fluid drain (torque converter, too), and give me an assessment at that time. I'm hoping the fluid and filter change will fix the problem, or at least kick it on down the road for a while.

Anybody had any experience with a product called "Dr. Tranny Instant Shudder Fix?" I've always thought of additives as snake-oil, but this one gets tons of rave (and verified) reviews on Amazon for addressing this specific symptom.

 

[Town]

I think you are going in the right direction to fix your problem which is primarily a 3 to 4 upshift and downshift. Adding an additive to fix shuddering may screw up the diagnostics. Additives are not generally thought to improve a broken transmission but may cover it up for a while.

 

[riverguy]

I think you are going in the right direction to fix your problem which is primarily a 3 to 4 upshift and downshift. Adding an additive to fix shuddering may screw up the diagnostics. Additives are not generally thought to improve a broken transmission but may cover it up for a while.

I have an appointment for the complete flush set for Monday, 1/8. The tech tells me they pump the old fluid out and flush with fresh. I asked him about draining the Town Car and he said Town Car's haven't had drain plugs since the '80s. Is that correct?

OK, so here's the other part: On our drive back from Oregon, the shuddering 3-4 shifts stopped. Smooth like the old days again. Possibly a spec of something temporarily messing with the valve body?

What's your take on this pump/flush process? I've heard (unlikely) stories about this damaging seals . . .

And after this, I'll leave you alone. I do really appreciate the support!

 

[Town]

Do you recommend Mercon V for the transmission flush/refill?

Yes, it is the fluid recommended for your car. I checked the owner's manual.

Good luck.

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[Slick Fan]

What's your take on this pump/flush process? I've heard (unlikely) stories about this damaging seals . . .

I have heard positive feedback from a couple coworkers who had their transmissions flushed at a reputable shop. Neither one said that any seals were damaged in the process.

Hope that helps one way or another, with your decision.

 

[Town]

The flushing of transmission fluid using the external machine cannot hurt any of the seals and components of the transmission. The external machine drains the old fluid through the cooler lines and pumps new fluid back into the transmission sump pan through the return cooler fitting. The engine is running and so the transmission pump is doing all the suction from the sump and pressuring it through the transmission and out the cooler line to the external machine suction pump. The flushing machine does the best job of removing all the old trans fluid safely, it does not apply any pressure to the internal transmission components.

My dealer goes the extra step of removing the trans pan and cleaning the magnet and replacing the filter.

 

[Town]

I have an appointment for the complete flush set for Monday, 1/8. The tech tells me they pump the old fluid out and flush with fresh. I asked him about draining the Town Car and he said Town Car's haven't had drain plugs since the '80s. Is that correct?

OK, so here's the other part: On our drive back from Oregon, the shuddering 3-4 shifts stopped. Smooth like the old days again. Possibly a spec of something temporarily messing with the valve body?

What's your take on this pump/flush process? I've heard (unlikely) stories about this damaging seals . . .

And after this, I'll leave you alone. I do really appreciate the support!

Glad to hear that shifting is good now. The tech is wrong about the torque converter drain plug, it was in use through the 2002 model year Town Car, but was deleted for the 2003 models and above. I also don't think the tech is describing the flush process accurately, it is a one step process of removing the old fluid and replacing the new fluid using the engine running the transmission as the means of moving the fluid through the engine. The flush process cannot damage seals since the flush machine removes old fluid through the outlet fluid line and provides new fluid through the input cooling fitting to the trans sump. The engine driven transmission pump moves the fluid from sump to cooling line to flush machine old fluid tank.

Have no fear the system works very well and replaces more old fluid with new fluid than any other procedure.

You don't need to leave us alone, your company is very pleasant. Good talking to you. Perhaps we can help again.

Good luck.

 

[riverguy]

Glad to hear that shifting is good now. The tech is wrong about the torque converter drain plug, it was in use through the 2002 model year Town Car, but was deleted for the 2003 models and above. I also don't think the tech is describing the flush process accurately, it is a one step process of removing the old fluid and replacing the new fluid using the engine running the transmission as the means of moving the fluid through the engine. The flush process cannot damage seals since the flush machine removes old fluid through the outlet fluid line and provides new fluid through the input cooling fitting to the trans sump. The engine driven transmission pump moves the fluid from sump to cooling line to flush machine old fluid tank.

Have no fear the system works very well and replaces more old fluid with new fluid than any other procedure.

You don't need to leave us alone, your company is very pleasant. Good talking to you. Perhaps we can help again.

Good luck.

I had the flush done today. $305! The tech said the old fluid was brownish and there was some sludge in the pan, but no metal. It shifts like new now!

Thanks again for all the support! It's so good to have folks around who actually know what they're talking about!

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[bigsid99]

OK, thanks for all the help! I have an appointment at a good transmission shop near home and I'll have them do a complete fluid drain (torque converter, too), and give me an assessment at that time. I'm hoping the fluid and filter change will fix the problem, or at least kick it on down the road for a while.

Anybody had any experience with a product called "Dr. Tranny Instant Shudder Fix?" I've always thought of additives as snake-oil, but this one gets tons of rave (and verified) reviews on Amazon for addressing this specific symptom.

I used that Shudder stop in red plastic bottle which I got at oreilly’s. It worked for my transmission, so far.
Bigsid

 

[Allerch12@]

I had the flush done today. $305! The tech said the old fluid was brownish and there was some sludge in the pan, but no metal. It shifts like new now!

Thanks again for all the support! It's so good to have folks around who actually know what they're talking about!

I have a 2017 MKC...80k mostly FWY miles...gone to crap....