Well, I will call them delusional if they think this. There is no way on God’s green earth that a faulty half-shaft is going to cause a rough idle while the vehicle is stationary and not moving. It ain’t goin’ to happen on a Subaru or any other car with half-shafts, driveshafts, or anything else.
It’s possible that your mechanic has done something other than an axle replacement to solve this problem - such as dinking around with that throttle plate screw that he should not have been dinking around with in the first place.
What you should do is invite any of those morons on the Subaru board who claim what you state to be true to this board and let them post that half-baked theory here. I for one would love to hear an alleged technical explanation behind this oddball reasoning.
(I don’t even want to mention this, but I worked for Subaru a lot of years and held a Subaru Master Tech rating, along with tickets for SAAB, VW, Honda, Nissan, and a Powerplant Rating as an aircraft mechanic also. I’d like to at least think I know how a nut and bolt goes together.)
So I guess folks that read this thread have a choice. They can follow the approach that myself and others have followed when they have this problem, and (more than likely) solve it. Or, they can believe you and do nothing, choosing instead to spout off without offering any solution at all. Works for you, but won’t work for them.
And for the record: I took the axle in, he pulled the old one, put in the new one, handed me back the keys. No other modifications - problem solved. You lose.
You’ve obviously chosen to avoid reading anything but your own rhetoric on this issue, which is disappointing.
It’s not rhetoric; it’s mechanical fact.
For what it’s worth, I’ve wandered around a bit on some Subaru and VW forums and don’t even post there because of the amount of utter BS that is being espoused by some of the alleged experts on there.
(Subaru examples; piston rings cannot be put on upside down, Subarus don’t use valve seals, mechanical lifters never need adjustment, etc, etc.; and this is from some of the so-called pros on there. Morons is a better word.)
Where did I say “do nothing”. Never said that. I said FIX the actual problem.
You or anyone else can think what you want but there is no way that an axle shaft has an affect on engine idle and causes vibration while the vehicle is in a stationary position. It has not happened, it’s not happening, and it’s never going to happen on any car that has ever been made. The ONLY way it will have an affect is if someone screws around with the O2 wiring while changing a shaft and forgets something. This could be entirely possible in your case because it is YOUR mechanic who screwed around with something he should not have been screwing around with; e.g., that throttle plate screw.
(FYI here. Messing with the idle screw can cause an engine to have an erratic idle in that sometimes it will be rough and sometimes fine. There’s a 100 things influencing this from ambient temps, humidity, barometric pressure, etc.)
I may just drop in and register on a Subaru board and see what kind of hogwash is being spouted there since you won’t invite them here.
Something else you should do in the meantime. Call the Subaru regional office in your area and pose this question to a service rep, or preferably service school instructor, and see what they say.
If you actually think this problem at a stationary idle is caused by an axle shaft then by the same logic, brake shudder, wheel balance, or wandering due to worn suspension parts can also cause a rough stationary idle.
He’s calling it a vibration that can be felt through the steering (in a later post) versus an actual engine idle problem.
Seems far fetched but I’ve seen stranger things when it comes to harmonics and resonant vibrations. If the shaft is indeed a different length than the OEM shaft, it is possible that it sets up a resonant frequency that amplifies the engine vibration to the steering knuckle whereas the OEM shaft length did not. At least, based on the limited information and taking what is presented on faith, that would be the only explanation I could envision.
Still incorrect in these last 2 posts.
Twin Turbo, the OP says the problem only occurs when the automatic transmission is IN DRIVE, the footbrake DEPRESSED, and the vehicle is at a DEAD STOP.
This means all of the axles are inert, still, motionless, not moving, dead to the world, placid, flacid, limp noodled, and are dead corpses at that point.
I posted this scenario on the Subaru site and I can’t wait to hear the technical explanation I asked for.
A rotating mass that is not rotating at all and is causing a vibration means the laws of physics have been eliminated. Jeez.
The torque converter, in the transmission, is rotating when the engine is idling. Therefore, could it (and any other rotating masses) vibrate harmoniously, or, inharmoniously? This physics question is too staggering for me.
A vehicle can have a torque converter shudder; this is very true. However, it’s never been a problem with Subarus, ever, and the OP says this problem is gone now.
The converter is spinning when the engine is running, but neither the axles, the stub axles that propel those axle-shafts, or the differential that propels the stub axles is moving so none of that can be an issue.
Nothing in the differential section of that transmission is moving either when the vehicle is stopped.
I read those posts on the other site and to be honest, about 95% of it is pure bunk, innuendo, and wild guessing. There’s a lot of “I heard” and “someone told me”, that axle shafts could cause this, etc, etc.
The legitimate 5% mentions things that could very well cause the problem; mounts, too low or too high an idle speed, vacuum leak, engine miss, etc.
Considering the OP says on the other site his idle was too low and then it was too high leads me to believe this whole thing is over someone not having the ability (the trusted mechanic he refers to) to find out why the engine is not idling properly. The OP was ALSO told on the other site that dxxxxd throttle plate screw was not to be dinked with.
Too bad he gets irate with someone who is trying to help him rather than his trusted mechanic. His trusted mechanic is the guy screwing around with his car, not me.
Look at the physics comment this way. Could you claim your engine has a crankshaft vibration in it if the engine is not running? The crankshaft is a rotating mass the same as the axle-shafts. Think of the half-shafts at idle and a complete stop as the crankshaft in a non-running engine.
I know the first thing I would do with the car if I had it in hand. Connect a vacuum gauge (a whopping 20 seconds or so of time) and determine what is going on engine wise with that thing. Cam timing off a tooth, weak cylinder, or whatever should show up instantly.
This spat has (fortunately for all of you) been carried elsewhere.
Just to remind any future readers that are having the same problem - a strong vibration when your Outback is at idle and in gear:
If you recently had an axle replaced (usually due to a CV boot/joint problem) and your mechanic used an aftermarket axle, it seems like a wise and relatively inexpensive solution is to ask your mechanic to replace the axle with a Subaru one (reman’ed or OE). Works for many people regardless of an explanation.
(Many people have had this happen without a timing belt change being involved, so you can ignore all of the stuff about the timing, throttle stop, idle, etc.)
In reply to the last thread, when the car is stopped in gear with the brake on, there is still torque going through the transmission to the axles. And with the equal length of the axles, the torque is going to go to the least path of resistance. That being any SLOP in the DOJ or CV of the defective axle. For you whom doubts this, maybe this occurrence wouldn’t prevail on a sideways mount engine with UNEQUAL length axles. …and yes i am from www.ultimatesubaru.org =^x^=
I can’t believe you are still arguing this. THIS THREAD is one of the “legitimate”, conclusive threads you claim not to exist.
The Original Poster has responded, and says the problem was fixed by installation of OEM axle!!!
Nobody is claiming that the vibration is from a rotating mass. OBVIOUSLY, the axle isn’t rotating at a stop. But the vibration is real.The vibration from the torque transmitted against the DOJ whilst in gear.
And BTW: Working for “several” subaru dealers over a few years doesn’t sit right to me. Sounds like they didn’t like youre work. Or maybe it’s you’re attitude.
Will drop in over there later.
And BTW: One dealer retired and closed the operation down. Another was part of a 3 franchise operation and due to some bad financial decisions went belly up. I was only a lowly tech, shop foreman, and service manager at one time or the other so I’m not that deep into the management loop.
And BTW: “youre” and “you’re” needs a little grammatical refinement.
Hi, missed all this for some reason. The other brand of axles from China is GSP. They are available from RockAuto.com and Advance Auto Parts.
As for the axle causing vibration at idle, yes and no. The axle will not cause the vibration, but it could cause the vibration to be transmitted or felt in the steering wheel. The engine probably vibrates as much now as it did before, it’s just that if the reman axle was a different length, it could cause the end of the axle to either bump or pull on the CV joint, causing a vibration in the wheel. and that in turn could be picked up by the tie rods and would be felt in the steering wheel.
There is a flaw in this theory though. With the inner DOJ on a Subaru, the inner ball race/balls are not at a fixed point in the outer shell of the DOJ. They all slide back and forth in the ball grooves depending on movement of the control arms. Think of bowling balls rolling in the gutters. Even if the DOJ was moving around like crazy, which it can’t, there is enough free play there that the DOJ movement would never affect the steering wheel.
If one can see the DOJ moving at all then the differential is trashed and a rough idle is the least of the worries.
That back and forth movement, or slop, is designed in on the inner joints, and not just on Subarus. It’s a fixed point on the outer joints.
Jeez.