Piston Slap: If Only We Knew Ye, Trooper!

Sajeev Mehta
by Sajeev Mehta

TTAC Commentator Dave M writes:

Hey Sajeev!

A question for you and B/B. Especially during cold weather my Trooper gets a ’clunk’ shifting from 1-2 (it’s a 4 speed automatic) and then back down. This coincides with a CEL. It doesn’t happen all the time. There are other times (even during cold) where the truck runs normally – no clunk, no CEL. Checking the CEL code and it indicates all four oxygen sensors (replaced last year); when no CEL no code to read.

My first thoughts were it might be time for ANOTHER transmission. But my brother says no, it has to be electrical since it’s intermittent. Any ideas where to start?

Sajeev answers:

Welllllllll…for starters you could write us with more info: stuff like the year/mileage/service history/CEL code totally wouldn’t hurt.

Perhaps it is time for “another” transmission, if we knew why you said it like that. Like maybe knowing the condition (look and smell) and age of the transmission fluid. Or perhaps the CEL isn’t fixed because Oxygen Sensors aren’t usually the problem: they are the messenger of a problem upstream. Maybe $10 in new vacuum line fixes the CEL, eliminate a leak that’s messing up both the engine and transmission’s parameters.

Or maybe you need a whole new transmission.

It’s kinda impossible to tell.

Come on son, us armchair analysts can’t judge a problem this complex with such half-baked info! That said, have at it, Best and Brightest.

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.

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Sajeev Mehta
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  • AllThumbs AllThumbs on Mar 19, 2014

    I'm just impressed someone has a 12 year old Trooper on the road. Joke. Sort of. The Trooper was a good car new. Unlike the Land Cruiser, say, it's not a good car old.

  • Dave M. Dave M. on Mar 19, 2014

    Hey thanks for picking ME!!! Sorry I was short on details. It's a 2001 2WD (poser!) LS model; the original transmission (the infamous GM 4L30E) was replaced at 60k (under warranty), and that one was rebuilt at 165k (and a transmission cooler added per suggestion by transmission shop - highly reputable local firm). It is now at 220k miles and reduced to vacation car status up north. Regarding the CEL, last summer before it hit the road the CEL came on and my mechanic mentioned all four oxygen sensors needed replacing (I didn't catch the CEL code). A day later the light went off and did not reappear until I drove it recently on vacation. As I said the CEL and clunking are intermittant. Kericf - thanks for the in-depth explanation. That will be checked out in the future. I didn't realize planetisuzu was still alive!

  • Dave M. The Outback alternates between decent design and goofy design every generation. 2005 was attractive, 2010 goofy. 2015 decent. 2020 good, but the ‘23 refresh hideous.Looking forward to the Outback hybrid in ‘26…..
  • Lorenzo Subaru had the ideal wagon - in 1995. The Legacy Outback was a straight two-box design with rear quarter and back windows you could see out of, and was available in brown with a 5-speed manual, as God and TTAC commenters intended. It's nice they're not raising prices, but when you've lost the plot, does it matter?
  • Bkojote Remember a month a go when Cleveland wanted to create a more walkable Cleveland and TTAC's 'BIG GOVERNMENT IS THE PROBLEM' dumbest and dullest all collectively crapped their diapers? Here's the thing- look on any American highway and it's littered with people who don't /want/ to be driving or shouldn't be. Look at every Becky on her phone during the morning commute in her Tucson, look at every Brad aggro driving his 84 month loan GMC. Hell look how many drivers nowadays can't even operate a headlight switch. You expect these people to understand a stoplight? In my neighborhood alone 4 people have been rear ended at lights from someone on their phone. Distracted driving over the past 10 years has spiked, and it's only going to get worse unless Becky has an alternative, because no judge is going to pull her license when 'she needs it to get to work!' but heaven forbid she not check fb/tiktok for 40 minutes a day.
  • Scott Shouldn't the The Italian Minister for Business be criticizing The Milano for being too ugly to be Italian?Better use of resources doing that....
  • Steve Biro Frankly, while I can do without Eyesight and automatic start-stop, there is generally less B-S with Subarus in terms of design, utility and off-road chops than with many other brands. I just hope that when they adopt Toyota’s hybrid system, they’ll also use Toyota’s eCVT.
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