By on February 3, 2010

TTAC Commentator NN writes:

My wife’s 04 Mercury Mountaineer (V6, AWD) recently hit 65k miles. The transmission had been clunking around noticeably lately, and I realized that:

a) These trannies are prone to fail

b) We hadn’t yet changed the ATF on the vehicle.

I am aware of the argument that some people make that when tranny fluid is old not to change it because the varnish build up, etc. helps to hold things together. But I thought 65k was still pretty young so I told my wife to take it in and get the fluid changed. She took it to a local non-franchise, non-dealer mechanic–just a fluid change and flush, no filter change as the mechanic said it wasn’t needed. The very next day the “O/D Off” light starts flashing constantly, which suggests that the transmission needs service. This is the first time we have seen this light.

My first thought is to make sure the mechanic did everything right on their end…i.e. didn’t leave the fluid level too low, etc. But in the end, I think this transmission is shot…as noted prior, it clunks in and out of reverse (with a delay usually), runs the RPM’s up during shifts like a slipping manual would, and clunks hard into neutral when coasting to a stop, also. My guess is that we are a textbook case of the last bits of the tranny holding out with the old fluid, and the flush was the end of it. The car, otherwise, is well liked…and paid off.

My question for you is what to do if the tranmission is indeed in need of service. I have read on other forums about how some fixes (solenoids, etc.) can run up to $1,000 and only solve the problem for a few months. Should I just pony up the $2k for a rebuild and hope that will last for another 5 years, or should we consider dumping the car? These Mountaineers/Explorers have a history of this transmission failing so I don’t want to play around and want to get to the bottom of solving the problem quick…this is my wife’s car, after all.

Sajeev Replies:

NN, if nothing changed since you emailed me, your nightmare scenario is not very likely. Most importantly, make no judgments until you find the error code that created the warning light! This is just as true for transmissions, especially with electronic 4WD systems with far more electronic stuff than yesteryear’s trucks and SUVs.

The only fly in the ointment is access to a transmission code scanner: sometimes you need to get a more sophisticated computer scanner than what’s normally offered. Luckily, with a $100-ish deposit, you can rent the correct scanner from many parts stores. So do just that, or get the codes from the mechanic.

Again the codes are crucial: don’t listen to the mechanics diagnosis, ask him for the code and the diagnostic tree followed to come to their conclusion. Like the Grand Marquis recently discussed (https://www.thetruthaboutcars.com/piston-slap-friction-modification-for-the-mighty-mighty-marquis/) a bottle of LubeGuard Red might be the only thing needed. I’d throw a bottle in right now, and see if anything changes.

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28 Comments on “Piston Slap: Not Exactly a Rugged Mountaineer Edition...”


  • avatar
    educatordan

    Sigh. FLUSHES ARE STUPID FOR OLD TRANSMISSIONS! Why put stress and strain on something old? There’s a reason we didn’t throw my 94 year old great-grandmother a surprise birthday party. If you can’t find a place that will just drain and fill it, don’t do it.

    • 0 avatar
      Geeky1

      I agree with you to a point, but… Is 65k really “old”? I worked as a service advisor doing German car repair for a few years, and I recommended that customers do fluid & filter changes on all of the MB/BMW/Audi/VWs we serviced that had “lifetime fluid” in their transmissions at least every 60,000 miles-or every 30k if they wanted to follow the same schedule that most manufacturers used to recommend for non-“lifetime fill” transmissions. I never had anyone experience transmission problems after a service @ <100k miles; I had one Mercedes that had issues after a service @ 150,000, but that's it. Maybe 65k qualifies as old on American cars or something. *shrug*

    • 0 avatar
      educatordan

      The biggest problem is that I’ve never seen a transmission flush done “right” something always gets messed up somewhere, machine operator error generally.

    • 0 avatar

      Agreed Geeky1. My (German) daily driver is two years older than the subject car, but has over 2X the mileage. It has a manual transmission but even with 8 years of commuting in stop & go traffic the shifts are smooth as silk.

  • avatar
    John Holt

    Here’s a link explianing the unfortunately “infamous” 2-3 shift flare issue in the 5R55E transmissions.

    http://www.explorerforum.com/forums/showthread.php?t=174202

    It can be remedied without a complete rebuild. There is a plethora of good transmission information in the ExplorerForums site that is stickied, just takes a while to sift through.

    Start buddying up with a good trans shop who’s done a lot of Exploder trannies – they are well familiar with the issues, and a good one will lead you through it hopefully without a complete rebuild.

    Oh yeah, and for the record on these – flushes are bad news if they’re not done regularly for the very reasons you state. However, oil needs to get changed to work correctly, so drain and fill every 1000 miles or so until you feel you have mostly new ATF. Chances are if the trans fails, it’s not the oil’s fault (unless the oil was completely cooked) – something was ready to go anyways.

  • avatar
    tedward

    My (family’s…I was young) experience with 4 automatic Ford trucks leads me to believe that you will be chasing this (O/D flashing specifically) down forever. Granted, they were older than an 04, and I’m citing the worst kind of anecdotal evidence right now, but run away (after fixing it as per Mr. Mehta’s advice). My prediction is that any fix is going to be short term, even a swap.

    On the other hand I still see my old ’96 Bronco on the road…being used (most aggresively) as a plow truck by a guy I know. The O/D light flashing away on the column shift. Maybe don’t fix and keep should be considered, although I wouldn’t.

  • avatar
    rtt108

    I’m not a mechanic, so perhaps someone with more knowlege will correct this.

    This may not be helpful to you, but for other readers … check your owners manual. Under service, what is the change interval on the ATF? I would expect something like 30,000mi (I always follow the severe service schedule). So my first guess is that by not serviceing your tranny you may have caused the problems you now are experiencing. (not trying to rub it in, but this may be helpful to others)

    Next, as the previous reply partly pointed out, it’s my understanding that “power flushing” a transmission is bad. It can dislodge debris in the tranny and cause it to circulate and clog stuff up. HOWEVER, dropping the pan and changing the fluid and filter (if applicable) is not only good, but necessary if you don’t want to rebuild your transmission.

    Lastly … “O/D Off” … unless I’m completely confused, means you have the automatic overdrive turned off ? Again, check your owners manual. There should be a push button somewhere near the shift lever to enable or disable the automatic overdrive. They probably hit the button during service. I’m not sure on this one though … there may be a difference between that “O/D Off” being on solid, or flashing.

    • 0 avatar
      John Holt

      Flashing “O/D Off” on Fords indicates a malfunction sensed by the TCU.

    • 0 avatar
      rtt108

      Thanks for the correction. After I typed in the post I got to wondering if there was a difference between the lamp flashing or staying on solid.

      Hopefully a decent tranny shop can track down the problem and fix it without too much cost. Now a days throwing $1000 at a tranny is only 2 or 3 months of car payments. I would think it would be financially worth it to have it repaired.

    • 0 avatar
      MBella

      Let me explain how a professional flush works. Most professional trans flush machines use the transmissions own pump to power the process. A trans cooler line is disconnected. The machine is hooked up to each side. The machine we have is self switching so it doesn’t matter which way you hook up the hoses. Some of the machines don’t have this feature and you have to be careful which way you hook it up. The transmission’s pump send fluid into the machine. It drives an internal pump that works similar to a turbocharger. This pumps new fluid out back in through the other line. The only difference between normal operation, and when the flushing machine is on, is that new fluid is is coming out of the trans cooler. It cannot dislodge any debris, because the fluid is circulating the same way it was designed to, and at the same pressure and volume.

      As I said above, a flush at 65K is still acceptable. Sometimes new fluid will fix an issue that the trans has, at least temporarily. Many times, on a transmission over 100K, the flushing out the varnished fluid will cause new problems. Regular fluid changes will keep this from happening.

      Also, for the absolute best fluid flush, changing the filter after the flush will give you the absolute best result. Dropping the pan alone will only let out about 1/3 of the old fluid. The flush machine will do 80% – 97% depending on transmission design. Something to be aware of also, is that the place doing the flush is using the correct fluid. Don’t allow them to use Dexron III/ Mercon in you VW for example.

  • avatar
    NN

    Thanks for the responses, folks. This scenario reared it’s ugly head back in December, and it is my wife’s daily driver. She drives about 25-30k/year for work and often carries our newborn in the car so a quick and 100% reliable fix was necessary.

    The mechanic at the fluid change shop recommended a valve-body rebuild and new solenoid for the tranny, but wanted a lofty $1500 for the work. I then went and got 3 competing bids for a rebuild, the best coming in at $2100 and having a one year warranty. I researched these vehicles more thoroughly and read lots of similar experiences…check out http://www.carcomplaints.com…this generation Explorer/Mountaineer is the #1 problem vehicle on record and the #1 problem is these transmissions. Sadly, failure at 65k is not that abnormal.

    So after the rebuild shop (Cottman) told me they had done tons of these Explorers and assured me they use higher quality components in the rebuild (apparently Ford has prescribed the higher quality parts themselves and applied them on newer generations), we went with the rebuild. My a$$ still hurts from the $2100 bill. Car drives fine, though…my only worry now is how long the rebuilt unit will last, and if it’s really supposed to be as good as an original.

    Also, Sajeev…this is a 100% fully sealed transmission with no dipstick to even check the fluid level, nevertheless add anything! A terrible design in more way than one!

  • avatar
    Ion

    Aren’t these “sealed” transmissions? how’d a non-franchise, non-dealer, run of the mil mechanic service one? I find it unlikely they ponied up and bought the machine to do it.

  • avatar
    conswirloo

    I hope its not 4WD(or sportrac or whatever they call it), if it is, expect the transfer case to NSFW the bed next(probably not under warranty with the transmission replacement). First hand experience with a 97 V6 explorer.

    If you look at consumer reports(I know, I know) for 8 years or so worth of explorers, the transmission is a constant black circle of death. The last year or two, they seem to finally have fixed it, and then discontinued the line entirely.

  • avatar
    gslippy

    Flush and fill is hokey if the filter isn’t changed. Always change the filter.

    Did they install OEM fluid, not something ‘equivalent’? It’s not worth saving $5 to avoid the higher price of OEM fluid.

  • avatar

    FLUSH = bad idea. Its just a scam for a place with a flushing machine to charge you more money. Get the fluid changed, that’s it.

    • 0 avatar
      MBella

      A trans flush is not a scam, if it is performed correctly. You cannot get to all the fluid by dropping the pan. A brake flush is also not a scam. Brake fluid absorbs moisture and will cause your lines to rust internally and brakes hoses to swell up if not performed every 2-3 years.

      Most power steering flushes however are a scam, because they only pump fluid out of the reservoir. However, if you want a god power steering flush, disconnect the return hose from the reservoir. Extend the hose into a container. While running the car, keep adding new fluid while someone steers the car from lock to lock. You are done when new fluid starts coming out of the return hose. Reconnect everything, and bleed the system by turning it from lock to lock until the pump stops whining, and a jerking sensation leaves the rack. Most places don’t do it this way because it can take a while to bleed the system. Sometimes you have to use a vacuum pump to get the air out.

  • avatar
    Don Gammill

    Regarding the “sealed” nature of the Ford 5R55 transmissions, if the “E” version in this generation of Explorer/Mountaineer is anything like the “S” version in Mustangs, then there is a small port in the bottom of the trans pan. Ford dealerships and transmission shops have a special tool (a pressured bottle, essentially) that allows them to check the fluid level and fill the pan through a ridiculously convoluted process that can’t be terribly accurate.

    At least two aftermarket performance transmission manufacturers sell modified (larger capacity) trans pans for 5R55 transmissions that include a dipstick tube and a dipstick. They’re not cheap ($250+), though.

    • 0 avatar
      Ion

      250’s not so bad, a similar pan for an AOD/E & 4R70W goes for about 180 from B&M, one for a PowerGlide runs about 120. Plus such a pan would allow you to do fluid changes yourself so it would pay for itself over time.

  • avatar
    plee

    I used to own an 03 Explorer V8 which stated clearly in the owners manual to change the trans fluid every 30,000 miles, which I did. I do not own it anymore so I cannot vouch for the transmission’s life span. We have changed trans fluid every 30,000 miles as recommended in a 1990 Taurus, 97 Sable, 2000 Sable and a currently owned 2004 Taurus and have never had a tranmission problem. We had the 2000 Sable until 120,000 miles.

  • avatar
    50merc

    With such a poor history of tranny problems (and not just in the Explorer), one has to ask: Is Ford even capable of designing a durable automatic? Who the hell is responsible for these 60K-and-bust designs? From personal experience I know the flashing “O/D Off” light can be hellacious to diagnose, let alone cure.

    • 0 avatar
      geozinger

      I had trouble with a tranny in my old Dodge back when they still had the 7/70 warranties. Long story short, I had the trans rebuilt twice on that car, the second time by this crusty old ****er who told me something interesting.

      At that time (early 90’s) he had been working on transmissions for 40 years, he said the car companies were taking (his term) “the meat” out of transmissions i.e. weaker gears, thinner cases, etc. to keep the costs of the car down. He said that most folks don’t keep their cars long enough. trade them out and the second owner (or later, usually out of warranty) get stuck with the crappy trans.

      In the intervening 20 years, the old ****er has proven himself right many times over, and not just with transmissions. I think that there should be some sort of consumer protection along the lines of the warranty on emissions controls. If the government forces the car companies to warranty emissions equipment to 100K miles, they should do the same with transmissions too.

      When I lived down South, it wasn’t unusual for me to rack up 20K miles/year in normal driving. If the tranny pukes at 65K, I probably still have two more years of payments. Lovely.

  • avatar
    Moparman426W

    I know that years ago ford had one of the most indestructible automatics ever made, the good old C6. It was right up there with the TH400 and 727.

  • avatar
    Moparman426W

    I’ve always changed my fluid and filters every 30k. The price of fluid and filters is dirt cheap, much cheaper than a new tranny.

  • avatar
    joeveto3

    I’m not completely against the tranny flush. I’ve had it done to my Grand Marquis with no ill effects. I think the issue revolves around older, neglected transmissions. Introducing mostly new fluid can be detrimental due to the high detergency of transmission fluid. It’s the same reason why engine flushing can be dangerous. Loosen the sludge (in a neglected or poorly designed engine), block an oil passage, engine becomes a boat anchor.

    As far as the rebuild goes, assuming the shop knows what they are doing, I would pay my money with good confidence the transmission will outlast the rest of the vehicle. The components used in the rebuild should be better than what was initially installed by the factory. The weak points are well known and addressed.

    Good luck with it.

  • avatar
    texan01

    My 1995 Explorer with the 4 speed version of this transmission finally bit the dust at 225,000 miles, and two fluid changes later.

    What killed it was a sticking intermediate servo that overheated the 2nd gear band, and shattered the adjuster and ripped the end of the band apart.

    That happened while climbing Raton pass in Colorado 3 years ago. I had the shop do a soft rebuild on it and it’s been peachy for 30,000 miles and 3 years. If it even lasts half as long as the original trans I’ll be happy with it as by then it’ll no longer be my problem.

    The Ford 4/5RR55E/A4LD are notoriously weak transmissions, they are descended from the Ford C3 trans that appeared in the Pinto if that says anything.

  • avatar
    Beelzebubba

    I had a 2004 Explorer XLT (4WD V6) with this same transmission (5R55-). In four years and 92,000 miles, it never gave me any trouble. My sister is driving it now, with just over 150,000 miles at this point and the tranny still works perfectly! I changed the fluid and filter every 30k when I owned it…and my sister has allegedly done the same! Maybe that’s how I/we managed to dodge this bullet?

    Now I have a 2007 Explorer (2WD, Eddie Bauer, V6) with the same basic transmission…but I haven’t heard of many issues with it in ’06 and newer models. I just passed 100,000 miles and no signs of trouble, but they’re all highway miles. It has spent 99% of those miles cruising in O/D (5th) gear, which is far less stressful than stop-and-go driving.

    Or maybe I’ve just been very lucky when it comes to transmissions! =) My mom’s old ’95 Jeep Grand Cherokee (4.0L, 2WD) is sitting in my garage with 205k on the godawful 42RE transmission that failed in every other JGC except this one! My mechanic thinks it has lasted so long because the Jeep came with the optional Heavy-Duty Towing Packing. That included beefed a beefed-up cooling system and power steering pump AND an auxiliary transmission oil cooler. That may be why it’s still working after 15 years and 200k miles when others a large percentage of them failed during the original warranty period!

  • avatar

    Had a 2001 Taurus that lasted about 89k miles before the tranny started to go out. Changed fluid/filter regularly even though it’s a pain in the ass on these cars and it still started to have problems slipping. After the $1800 quote to repair it we traded in the car instead of fighting with it. A lot of other small things started to go wrong at the same time. Plastic valve covers leaking, coolant reservoir cracked, alternator went bad (they must be made of solid gold at over $300 for a new one), etc…

    At the same time I had a manual Ranger that went over 200k miles without ever changing the fluid and my cousin still drives it. Never had an issue other than clutches.

    By the same token, I have a 98 Rodeo that has been used and abused off road and as a daily driver. I have over 200k miles on it and changed the tranny fluid twice. Recently it started slipping and shifting really poorly but when you would turn it off and back on it would be fine. After reading some owner boards I found out it was a dirty gear position sensor. Took it off and cleaned it and now it runs like new again. It’s never been a smooth transmission, even new, but it sure has been a trooper. The only stupid thing about it is there isn’t a dip stick. There is a drain bolt, and and check bolt, you just add fluid in the check hole till it spills out. It’s messy and ridiculous, but the tranny has held up. The shop manual is one that tells you not to change the tranny fluid at all unless used for heavy towing.

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