Piston Slap: Damned If You Do…

by Sajeev Mehta

Updated: May 16th, 2014 Published: May 28th, 2012

Kurt writes:

Dear Sajeev,

I’m writing about if/when/how to change the transmission fluid in modern automobiles. It’s been my experience when changing the fluid on a vehicle with > 100,000 miles and original tranny, the odds of trans problems within 5,000 miles rise dramatically. The consensus on the interwebs is this was true for older cars, but not necessarily modern vehicles using synthetic fluid. First my history…I’m only listing the cars where I actually changed the fluid. 89 Suburu GL – Fluid Changed at 120,000, total trans failure at 125k. 94 Chevy S10 blazer, trans fluid change at 115k, trans failure at 123k. Current: 2006 Honda Odyssey – Trans Fluid Change at 95K, Torque Converter starting to go out at 100K (yeah, I know this is a weak spot on this vehicle regardless) – wondering if I should change out the rest of the fluid before having someone look at the torque converter?. Additionally what to do about my 2003 Chevy Trailblazer LS (2wd) …..145k, original transmission, original owner, no trans fluid changes ever. The quick lube joint says fluid color is off – looks good enough to me though. I’d like to keep the truck a few more years due to the blood sweat and tears already invested in repairs.

I’ve read that Trans Fluid power flushes can cause more harm than good, and a standard fluid change only swaps a % of the fluid – normally needing 3 of those to get a full fluid swap. Add the twist of certain vehicles needing “special” fluid such as Hondas and it’s hard to say if my failures are due to improper technique by improperly trained quick lube employees, improper fluid, or if changing the fluid isn’t really needed! I always say “I’ll change the trans fluid when the trans fails”. I’m a mild wrench head, some blacked fingernails to prove it ….if my setup allowed it I’d love to change my own fluid – no one cares as much as the owner. However I stopped changing my own fluids after an Exxon Valdez-like accident on my driveway. Any advice on this topic?

Sajeev answers:

Wow, you totally have good luck with transmission fluid changes! Why not go for a fourth time and see where lady luck takes you?

Or not.

And that’s the big problem: usage of the word “or.” Because, during hindsight analysis, realizing that your ATF-replacement-cum-gearbox-implosion led to a lot of “or” conversations in your CSI-like TV show analysis of the culprit. Maybe there was nothing left of the clutch’s friction material when the old fluid went in the drain pan. Or someone put in the wrong fluid. Or it wasn’t enough fluid. Or too much. Or some combination of all the previous “or” statements.

Fun, huh? So in your case…

With your driving conditions, track record on transmission failures AND knowledge of the pitfalls associated with these fluid changes in mind…would you do this a fourth time? I suspect that no matter the machine, your climate, driving style and ATF changing schedule makes this a bad idea. Don’t do it.

#TransmissionFluidChanges

Sajeev Mehta

More by Sajeev Mehta

Comments

Join the conversation

3 of 40 comments

Kurth54 on May 30, 2012

Original Poster Here! There are a few issues at play, and I think you've all mentioned them. 1) Bias to change the fluid only once a problem is detected. GUILTY on my 2003 TB....I did the change 2 months ago, slip got worse, cut my losses, driving a new 2012 Camry now. 2) The 89' Sub, '94 TB were used car lot cars - who the heck knows what was done to them before I owned them. I changed the fluid before detecting problems - most likely trans was at the end of the line anyway - coincidence?? 3) The 06 Odyssey - that darn torque converter seems to go bad for everyone - its worse every day, having trans fluid changed today with false hopes the problem lessens. I guess my personal dilemma is one of trust vs time. Its hard to find a mechanic you trust.....sometimes you may trust the head guy but he's not the one working on the auto. Doing it myself....learning curve...Exxon Valdez in Driveway. Thus ignoring the issue until there is a problem, creating an even larger problem! The other factor is paying dealer vs doing it yourself. A rebuild may be less expensive than paying for 5 trans fluid changes (each 30k over 150k miles)unless you DIY - in this case - also Let 'er ride! The '12 Camry has no stated Trans fluid swap interval......let 'er ride!

Like Reply
- 28-Cars-Later on May 31, 2012
  
  Let 'er ride! Git er done! :) I'd rather pay for the regular fluid changes and risk wasting money than potentially being inconvenienced by a blown tranny and subsequent tow to the shop.
  
  Like
28-Cars-Later on May 31, 2012

Excellent topic for discussion since the automatic transmission is sometimes viewed a mysterious sealed unit which only the Hogwarts kids can conjour up spells to fix. The advice I was recently given from an Aamco owner who services all of my cars was "here [in Pittsburgh] you have extreme heat and extreme cold, the fluid in the pan [of a car] should be changed in no less than 25,000 miles"

Like Reply

Recent Comments

Amy I owned this exact car from 16 until 19 (1990 to 1993) I miss this car immensely and am on the search to own it again, although it looks like my search may be in vane. It was affectionatly dubbed, " The Dragon Wagon," and hauled many a teenager around the city of Charlotte, NC. For me, it was dependable and trustworthy. I was able to do much of the maintenance myself until I was struck by lightning and a month later the battery exploded. My parents did have the entire electrical system redone and he was back to new. I hope to find one in the near future and make it my every day driver. I'm a dreamer.
Jeff Overall I prefer the 59 GM cars to the 58s because of less chrome but I have a new appreciation of the 58 Cadillac Eldorados after reading this series. I use to not like the 58 Eldorados but I now don't mind them. Overall I prefer the 55-57s GMs over most of the 58-60s GMs. For the most part I like the 61 GMs. Chryslers I like the 57 and 58s. Fords I liked the 55 thru 57s but the 58s and 59s not as much with the exception of Mercury which I for the most part like all those. As the 60s progressed the tail fins started to go away and the amount of chrome was reduced. More understated.
Theflyersfan Nissan could have the best auto lineup of any carmaker (they don't), but until they improve one major issue, the best cars out there won't matter. That is the dealership experience. Year after year in multiple customer service surveys from groups like JD Power and CR, Nissan frequency scrapes the bottom. Personally, I really like the never seen new Z, but after having several truly awful Nissan dealer experiences, my shadow will never darken a Nissan showroom. I'm painting with broad strokes here, but maybe it is so ingrained in their culture to try to take advantage of people who might not be savvy enough in the buying experience that they by default treat everyone like idiots and saps. All of this has to be frustrating to Nissan HQ as they are improving their lineup but their dealers drag them down.
SPPPP I am actually a pretty big Alfa fan ... and that is why I hate this car.
SCE to AUX They're spending billions on this venture, so I hope so.Investing during a lull in the EV market seems like a smart move - "buy low, sell high" and all that.Key for Honda will be achieving high efficiency in its EVs, something not everybody can do.