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Discussion Starter #1
Had transmission serviced again at over 200,000, has always been maintained. Ford said not to do this again at this mileage, that it would cause more damage than good. Trans has worked fine, until a few weeks later - trans seemed to not shift, as I stepped on gas the tach would seem to rise in unison, as if a direct connection, instead of shifting. RPM went to 4 to 5 or so - coasted to a shoulder, think I put the car in neutral - when i then put car in drive, transmission was normal. I had looked at trans indicator several times when it was acting up, it was in drive. Car drove fine west of the way home, though burning smell - and has driven normal the past few days.
What happened? Did the trans flush loosen some clutch material or something, and it hung up - then burned off? Is it really bad to flush a transmission this high mileage?
 

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You are probably right in assuming that the flush caused you problems. Hopefully, it is temporary and not serious. Why didn't you follow Ford's advice? It was probably based on their experience.
 

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What happened? Did the trans flush loosen some clutch material or something, and it hung up - then burned off? Is it really bad to flush a transmission this high mileage?
Well, I service my trannys at 30K miles and have for 30+ years. Given the duration that I'm sure the service to this vehicle was at, there can be a buildup of material on the clutches (normal) that happens over the years, this actually makes/enhances the clutch packs lockup..... the bad news is that if you change the ATF at the recommended 100k miles, chances are the oil is tired and you got anywhere from a little to alot of extra wear on the clutch packs..... a little wear no big deal, a lot, well that is what was making things connect firmly and when you R&R the fluid (whether you flushed it or did a conventional DC the hose and let the pump push out the fluid and refill, those particulates got released and either 1) reduced the bite of the clutch packs or 2) went into the valve body and is making something "stick".
 

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The flush process involves reverse flow of the fluid. And yes, it will dislodge debris and affect the valve body. I used to, but no longer recommend transmission flushing.

Last year in an attempt to extend a transmission in the daughters 2006 Jetta, I had the transmission flushed. The service department indicated the unit was at the end of its life and needed replacement at a cost of $5000. Took a chance and spent $240 to have it flushed and it worked great for 2 more months then out of the blue it started bucking the car and slamming in drive and reverse. Dumped the car and she now drives a 2013 Cruze Eco that cost as much as the transmission would cost to replace in the VW.

The Dodge scat pack has no service interval listed by Dodge. Dodge uses a ZF (german) design transmission and made a few changes for interface purposes and calls it a torqueflite transmission. But it's still a ZF 8HP70 8-speed trans and ZF recommends the filter and fluid change every 60,000 miles even though Dodge says none is required. The fluid is super expensive and the filter is integral with the pan and requires bringing the fluid to a sepecific operating temp after initial fill to check fluid level at the fill hole. Dealership cost to service the trans (cough) is $750. I buy a kit from BND for $250 and do it myself and save hundreds.

On a modern car I would just confine transmission servicing to filter changes and refilling fluid according to manufacturers procedures. The big question is when to service the transmission because many makers like Ma MOPAR do not list any recommended service but the people that designed the damn thing do recommend regular service intervals. I don't have confidence Ford is any better.

Do your due diligence and cover the bases and do what your wisdom guides you to do.
 
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Discussion Starter #5
You are probably right in assuming that the flush caused you problems. Hopefully, it is temporary and not serious. Why didn't you follow Ford's advice? It was probably based on their experience.
My regular service advisor told me he would not have flushed it at that mileage - so it was after the fact. I was wondering if that was really good advice -
 

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This subject had been brought up a few years ago in an article that I read. Like others have mentioned the worn material from the clutches is floating in the old fluid and once that is gone then you have nothing to give any friction to the clutch plates to engage each other if they are worn out. That gritty particulate is pretty much all that will make the trans work.
This is why if a transmission is really high mileage it's best to just add some Lucas transmission fix to it and call it a day. It'll rejuvenate the hydraulic characteristics of your old fluid somewhat, make a slipping trans not slip, and also stop seal leaks. You may have to drain some fluid out from a trans line or the pan if it has a plug. I've put that Lucas in a few transmissions over the years and it is is a miracle worker. Transmissions that were slipping bad, shifting sloppy, and in definite need of a rebuild went many, many thousands of miles afterward. Lucas is really thick stuff and needs to be warmed if it's cold in order to flow out of the bottle.
 

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Discussion Starter #7
As the transmission is shifting perfectly again now, and just had a fresh fluid change and flush, should I wait until symptoms reappear before I add the lucas transmission fix?
 
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