Piston Slap: Byzantine Transmissions in Frozen Highlands

Sajeev Mehta
by Sajeev Mehta
piston slap byzantine transmissions in frozen highlands

Mehran writes:

Greetings to you Sajeev and your evil twin Sanjeev, (yeah he’s dead to me – SM)

First of all thank you very much for answering my other question, just to give you an update on that, I ended up not buying the extended warranty. Now we recently bought a 2012 Toyota Highlander Limited to replace my wife’s old car(V6, 5 Speed automatic with the towing package which adds the trans cooler) it has 34K miles and this one has the extended warranty (100K or 2019). The issue that we have with the car is as follow, after a cold start (in the morning) if I put it in any gear (D or R) something funny happens, the transmission acts funny, it goes in and out of the gear couple of times. For example if I want to back-out of the garage when I put in R and give it a little gas it starts going but for a quick second it seems like that the transmission dis-engages and then re-engages and the tachometer jumps from 1K to 3K. If I wait about 10 sec after I start the car and then put in gear everything is OK.

The other day something strange happened, 3 min after cold start, I wanted to merge onto the highway so I mashed the gas all the way to the floor but it stayed in the same gear and did not kick down, now this has only happened once.

I did take it to the dealer and they gave me the “Could not replicate the issue” answer. I looked at the Highlander forums but did not find anything.

Any idea what might be the issue? I looked at the trans fluid, it seems OK and there is no evidence that the previous owner has done any towing with the car and it has always been serviced at the dealer.

Regards,


Mehran

Sajeev answers:

Automatic transmissions (and transaxles) are smart cookies, what with all their fancy electronic controls controlling a byzantine system of fluid pipes, valves, clutches, fans etc. There’s a reason why internal transmission problems are normally handled by repair techs with a particular set of skills. Like this guy:

If there are no check engine lights, the electronics are probably spot on. That leaves the fluid or that byzantine system to blame. Since your ride is under warranty, I’d leave it with them overnight to see if they can recreate the problem first thing in the morning. Pick an especially cold week for this, and insist it’s kept outside (if they don’t already). Odds are the dealer is right, it’s operating within specifications. It’s just that the fluid is maple syrup-ish when cold.

There’s a good chance that switching to fresh fluid (maybe even synthetic, if this is true) will help the byzantine system work better when cold, mostly because newer fluid could be more viscous when cold. That is, cold fluid can be thicker, harder to move in the system and resulting in everything moving much sloooooower. Be respectful of that and the transmission will respect your time and money.

If you want to keep the Highlander past the warranty, consider a preemptive fluid change at 75,000-ish miles.

[Lead image: Shutterstock user Pit Stock]

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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  • George B George B on Dec 02, 2014

    There is a phenomenon with automatic transmissions called "morning sickness" where clutches engage slowly when the transmission is cold, but operate normally once the transmission warms up. Generally it's a bad sign of expensive repairs in the future. Unexpected in such a relatively new vehicle. I'd leave the car parked at the dealer overnight and make an appointment with the service department to demonstrate the problem from a cold start with you present. I have a beater with a bad transmission that has survived more than a year with severe morning sickness. For cars worth less than the cost of transmission repairs, transmission failure can be delayed by being very careful how you drive when the transmission is cold. Wait for clutches to engage for reverse or drive before accelerating slowly. I have to shift the automatic manually for about the 1st mile. Shifts fine once it warms up.

    • Danio3834 Danio3834 on Dec 02, 2014

      Sometimes a shot of brake fluid down the dipstick will at least temporarily help a morning sick trans. It helps swell any leaking seals and can make a difference if that's the problem.

  • Danio3834 Danio3834 on Dec 02, 2014

    Sounds like a hydraulic pressure problem not applying the clutches correctly. It could be a solenoid or mechatronic/valve body issue not directing the pressure correctly, or could be a leak in a clutch circuit. Either way, the dealer needs to have the vehicle under the conditions which it occurs so they can duplicate it and see what is and isn't going on inside the transmission. Keeping on them about the issue even if it can't be duplicated at the time helps your chances of getting it covered outside the warranty if it outright fails later.

  • Jeff S Corey--We know but we still want to give our support to you and let TTAC know that your articles are excellent and better than what the typical articles are.
  • Jeff S A sport utility vehicle or SUV is a car classification that combines elements of road-going passenger cars with features from off-road vehicles, such as raised ground clearance and four-wheel drive.There is no commonly agreed-upon definition of an SUV and usage of the term varies between countries. Thus, it is "a loose term that traditionally covers a broad range of vehicles with four-wheel drive." Some definitions claim that an SUV must be built on a light truck chassis; however, broader definitions consider any vehicle with off-road design features to be an SUV. A [url=https://en.wikipedia.org/wiki/Crossover_(automobile)]crossover SUV[/url] is often defined as an SUV built with a unibody construction (as with passenger cars), however, the designations are increasingly blurred because of the capabilities of the vehicles, the labelling by marketers, and electrification of new models.The predecessors to SUVs date back to military and low-volume models from the late 1930s, and the four-wheel drive station wagons and carryalls that began to be introduced in 1949. The 1984 [url=https://en.wikipedia.org/wiki/Jeep_Cherokee_(XJ)]Jeep Cherokee (XJ)[/url] is considered to be the first SUV in the modern style. Some SUVs produced today use unibody construction; however, in the past, more SUVs used body-on-frame construction. During the late 1990s and early 2000s, the popularity of SUVs greatly increased, often at the expense of the popularity of large [url=https://en.wikipedia.org/wiki/Sedan_(automobile)]sedans[/url] and station wagons.More recently, smaller SUVs, mid-size, and crossovers have become increasingly popular. SUVs are currently the world's largest automotive segment and accounted for 45.9% of the world's passenger car market in 2021. SUVs have been criticized for a variety of environmental and safety-related reasons. They generally have poorer fuel efficiency and require more resources to manufacture than smaller vehicles, contributing more to climate change and environmental degradation. Between 2010 and 2018 SUVs were the second largest contributor to the global increase in carbon emissions worldwide. Their higher center of gravity increases their risk of rollovers. Their larger mass increases their stopping distance, reduces visibility, and increases damage to other road users in collisions. Their higher front-end profile makes them at least twice as likely to kill pedestrians they hit. Additionally, the psychological sense of security they provide influences drivers to drive less cautiously. https://en.wikipedia.org/wiki/Sport_utility_vehicleWith the above definition of SUV any vehicle that is not a pickup truck if it is enclosed, doesn't have a trunk, and is jacked up with bigger tires. If the green activists adhere to this definition of what an SUV is there will be millions of vehicles with flat tires which include HRVs, Rav4s, CRVs, Ford Escapes, Buick Encores, and many of compact and subcompact vehicles. The green movement is going to have to recruit millions of new followers and will be busy flattening millions of tires in the US and across the globe. Might be easier to protest.
  • Sckid213 I actually do agree that most Nissans are ultimately junk. (I also think many BMWs are also). I was talking challenging the 3 in terms of driving dynamics. Agree all were failures in sales.
  • THX1136 More accurately said, we are seeing exponential growth in the manufacturing capabilities in this market. Unless, of course, all those vehicles are sold with customers waiting until more a produced so they can buy. Indeed, there are certainly more EVs being purchased now than back in 2016. Is demand outstripping manufacturing? Maybe or maybe not. I sincerely don't know which is why I ask.
  • ToolGuy The page here (linked in the writeup) is ridiculously stupid https://www.tyreextinguishers.com/how-to-spot-an-suvLike, seriously stupid, e.g., A) Not sure that particular Volvo is killing the planet as quickly as some other vehicles we might choose. B) A Juke is "huge"??? C) The last picture shows a RAV4 Hybrid?
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