Subaru AT

As soon as it gets around 35F the transmission on our Legacy shifts with a loud clunk in every gear until it is warmed up.Until then we shift manually but still get this awful clunk occasionally.This happens on the upshifts only.
The dealer checked it out and changed the ATF but it still it persists. We are afraid that with the Wisconsin winter coming that will be a death sentence for the car. Any ideas???
PS: According to Googles forum it seems we are not the only ones with that problem.

Subaru Legacy Automatic
Model-Year ?


I have same thing on my 06 AT forester. It’s been going on for past 3 years and as with yours it’s only when it gets cold.
Mentioned it to the dealer couple of years ago and they said it’s normal.
So far i have no other issues with it and probably put around 60k miles after the symptom first started.

the easiest way to reproduce mine is to accelerate modestly when the car is still cold and at some point let off the throttle for couple of seconds and then try to accelerate again. When i press the gas again it almost feels like the transmission slips for a fraction of the second building up the revs and then suddenly engages with engine moving faster than the transmission. It’s almost like a clutch dump in MT car.

It only happens when the car is cold. Once warm it goes away.

To add to CSA’s question I might ask how many miles on the car and how often has the transmission been serviced before the problem started?

Automatic transmissions should be serviced every 30k miles and the major reason why you are not the only one with that problem as you put it is because very few people maintain their automatics properly.
The transmission is an afterthought for most people until a problem develops and THEN fluid changes and whatnot come to mind. Sometimes it may help, often it doesn’t.

Next step is scan the car for codes to see if anything is present.

what do you mean by “transmission service”? Even the manual doesn’t have anything of such nature stated.
I changed trans fluid (yes only 4qt as you can’t get more out without doing the flush) at 70k and the problem still persists.

Transmission service means changing the fluid and the filter unless its a transmission with a non-serviceable internal filter that cannot be changed short of taking the transmission apart.

Factory manuals are often a bit skimpy on what a car really needs and this applies to every car maker, not just one. The reason for those skimpy recommendations is because it’s a PR move. It’s designed to make car owners think their vehicles need far less maintenance than they really do need.

Some examples are 100k miles spark plugs, 100k miles or eternity transmission fluid, and “lifetime” fuel filters.
A double whammy can be applied to engines with mechanical valve lifters. The first is the poor recommendation of checking valve lash every 100k miles or more. In reality it should be every 30k miles. The second falls into the Ludicrous category and that’s the recommended method of actually inspecting that lash. It’s stated that the lash should be checked “audibly” (No way will this work) or the even more ludicrous comment that the lash should be adjusted if the engine is running rough.
If an engine is running rough due to tight lash this means one of two things:

  1. The engine is going to need an expensive valve job.
  2. The engine will need an expensive valve job in the foreseeable future even if the lash is adjusted.

It only takes a few miles of tight lash on an exhaust valve to cause damage. Once that microscopic pitting or etching starts the damage is done and will worsen with miles accrued. In really severe cases replacement of the cylinder head may be required although this is not the norm. It has happened though.

I’ve never heard of anyone adjusting valves on cars that often go beyond 200k miles.
It’s not 1950s anymore and modern engines are virtually maintenance free if you change oil periodically (not at 3000miles anymore either) and do the other things like spark plugs, filters and cables.
There is no need to adjust any internals.

Same with transmission: if there was a need to replace/flush the fluid every 30k, why wouldn’t it be stated in the manual? Even if not really needed it would be another way to lure customers in to the service bay at dealerships and rape them for some ridiculous amount of money because manual says so.
I can see a periodic trans fluid change every 100k or 60k miles but anything more often seems like it’s completely unnecessary.

My forester has not seen dealership bay for anything other than the warranty work on the leaking head gaskets. I do my own oil changes every 6-8k miles, change air filter every year and spark plugs every 60k.
Did my timing and water pump along with tensioner and pulleys/idlers. Engine runs like a champ and I don’t foresee doing any valve adjustment ever.

You are beyond dead wrong in your assessments. Have you actually ever inspected or adjusted a mechanical lifter? I’ve been doing it for over 35 years and believe me, it’s a necessity and often needed more than not.

I told you why the manuals provide bogus info like this. It’s to promote a warm fuzzy “my car doesn’t need a dxxxxx thing” feeling and the manuals have nothing to do with the dealers other than the dealer performing the services that the factory lists, which are often way shy of reality.

For most people ignoring valve lash is not a problem. For the minority who develop a problem it’s going to be an expensive lesson.
Case in point would be the lady who posted on this forum last year about her rough running Subaru. This turned out to be tight valve lash and this led to a 3,000 dollar estimate to fix.

For what it’s worth, we had a Subaru come into the dealership once that was barely running. It was so pathetic the car could not pull itself up the hump into the shop so it got pushed in.
The cause? Tight lash on all cylinders. Knowing this was an exercise in futility I adjusted the valves and ran another compression test. No dice, so out the engine came and both heads were removed. The valve seats were burned so badly that both heads were not repairable and required new ones at great expense.

The kicker? This car only had 7k actual miles on it and warranty would not pay for it because apparently the owner detected a problem early on, and fancying himself to be a mechanic, checked the lash himself. He zeroed out every adjuster and there you go; a few hundred miles later a trashed engine.
The above is the worst case scenario but many other cars fall into a lesser expense

You are also dead wrong about oil change intervals because many cars may need that oil changed not only at 3k miles intervals but based on time, the environment, driving habits, and so on.
Do a net search about oil sludging problems and you will find all of these people blaming the car, the engine, the car maker, the oil companies, the Vatican, and the Big Bang for those problems but it all comes down to one thing; they simply aren’t changing the oil often enough.

Same goes for trans fluid. Most trans problems are caused by lack of fluid changes and people only change it when a problem develops. At that point Elvis has left the building in most cases.

good info above but I’m not convinced. It’s 21st century. Things don’t need to be adjusted anymore. Why would valve lifters need to be adjusted other than due to abnormal wear caused by abuse or lack of any maintenance along with ignoring the signs of engine in trouble (CEL or abnormal noises).
If adjusting lifters was even slightly needed, greedy dealer would not omit to mention this to unsuspecting customers hoping for some big $$ coming their way.

I’m pretty involved in the local subaru community and know people working on engines on daily basis and no one ever mentioned something like this. Yes, spun bearings, blown turbos or thrown rods do happen but they usually happen on busted subaru engines due to poor or lack of tuning on engines that have aftermarket parts bolted on.

As far as the oil interval, I trust more the Used Oil Analyses that I do every time rather than some Oil industry invented hype of 3000 mile interval.
I recently did an analysis of synthetic oil that was run for 16000 miles. Would you like to see that?

You’re as dead wrong as can be and still out of the loop on things.

The dealer not mentioning it and gouging you for extra money? Simple reason; almost every service manager and service writer is mechanically inept. They earn their living by talking and many younger mechanics, fresh out of trade school, are also oblivous to this.

You’re “involved” in the local Subaru community? Well, so am I after having worked for 3 Subaru dealers as a mechanic, shop foreman, and service manager along with running my own shop.

I would like to see the oil analysis; especially the spec about the coked oil. Since coked oil is pretty much stuck to the inside of the oil galleys and whatnot and will not be dislodged by circulating oil that would be interesting.

I guarantee you that what I’m telling you is based on honest, accurate mechanical principles and any mechanic who doesn’t see this is a backyard hack. As to the valve lash there’s a reason why years ago I bought, at no small expense, various specialty tools for performing that procedure on Subarus, VWs, SAABs, and so on.
Why did I buy the tools? Because I want my own and when I need them I want them right then. I do not want to go looking for a tool that has been misplaced or stolen nor do I want to wait my turn until someone else is done with the shop’s tool.

Ask yourself why Subaru (and other car makers) send those tools to the dealers (dealers have no choice) and the dealer has to pay Subaru of America for those valve lash tools. Of course, with the prevailing attitude those tools are just lying in the tool room collecting dust…

The 21st century hasn’t done a thing to change how the fundamentals of how the internal combustion engine works. There are lots more bells and whistles hung on them. But mechanically it is the 1950s - you’ve got pistons to suck in air/fuel, compress air/fuel; and get blasted down by combustion to rotate a crank shaft. To let air in and exhaust out you have valves. Valves are driven by cam lobes on the cam shaft.

Hydraulic lifters work by oil pressure and never have to be adjusted (they self adjust by oil pressure so they’re either holding pressure or not). Mechanical lifters are still just mechanical lifters - bits of metal pushing other other bits of metal. They wear, they expand/contract with heat, and they need to be adjusted. Just because most people ignore it doesn’t mean it ain’t so and doesn’t mean lack of adjustment doesn’t cause problems.

Those lock nuts and thread adjusters on a Subaru are the same ones used back in 1994, and in 1984, and in 1974 and they’re also the same adjusters that Subaru used to recommend adjusting initially at 1000 miles and every 15k miles afterwards.
As a matter of fact, Subaru used to pay for that 1000 miles check but the bean counters decided they could save some serious money by claiming it was not needed.

Mechanical valve lash inspection is not just confined to Subaru. It also applies to any vehicle with solid lifters over the years including Honda, Toyota, Nissan, VW, SAAB, Volvo, and even dating back to some of the old performance engines such as the 426 Hemi.

As I said, the majority won’t have a problem by ignoring this but a small minority will. The purpose of the inspection and adjustment is for the member of the majority to make sure that they don’t become a minority member.
Most new minority members then start screaming to the heavens, cursing the mechanic, and threatening lawsuits for a lousy design, no one told them it had to be done regularly (may have a point there), and so on.

While on a motorcycle trip to South Dakota some years back I ran into a guy (member of the Bandidos Motorcycle Club actually) on the side of the road in NE Colorado. He was riding an antique Harley with a recently rebuilt motor and was from Lubbock, TX.
Stopping to help and doing a bit of roadside diagnostics I found that he was losing compression. After popping the valve cover retainers loose I discovered that both exhaust valves had tightened up. I adjusted them but it was too late; both exhaust valves were burned and there was nothing I could do for him as I was on 2 wheels too.
It’s called (in this case) valve stem stretch. The only saving grace was that he said he had some buddies who were going to be along in an hour or so and one of them had an emergency truck.

Think this guy wished those valves had been checked?