[Strobie]

I have a 2010 forester with a manual transmission. It has a really bad clunk or jump in the suspension when you turn in a parking lot or a parking space, either direction and in forward and reverse. I thought it was a CV joint so I changed both axles and both front wheel bearings since I was in there. This solved nothing. This is a similar clunking like a posi-traction reared with new clutches but is more violent in the front. This happens after the transmission is warmed up either by driving 5 miles or leaving it idle for 15 minutes. It is fine on a cold engine/transmission. It also developed a whizzing sound from the transmission or drive train after warm-up, noticed on de-acceleration. The sound is like the gears are meshing, just bad, just enough so you can hear and feel it. I also drained and changed the transmission/front differential fluid. None of this solve the issue. What could it be? Any advice?

 

[karlaudi]

What part of the world are you located and how many miles do you have on the Forester?

How long have you owned it in terms of miles?

Did you find any metal sheen and / or metal chunks when you changed the transmission fluid?

Have you checked the driveshaft?

Engine and Transmission mounts?

The heat shields for damage or being loose?

How is the clutch action?

How does the transmission behave when shifting?


My guess would be your differential is damaged somehow, but it is hard to know without being there. New to Subaru myself, I ,so far, understand that Subaru manual transmissions are robust, but they need proper routine maintenance to stay that way.

 

[Strobie]

Wisconsin-USA
Owned Ruby for less than a year, bought it at a new car dealer off the used lot.
No metal, fluid actually looked clear/clean. (Okay, that was a signal to me, something might have been up, that was why the trade in).
Drive shaft is good and tight.
Engine and transmission mounts are sound.
Heat shields are good.
Clutch is operating as it should.
Shifts good except it began to not mesh going from 4th to 5th without the clutch...synchro issue or not use to it, just not enough driving by me. It is my GF's vehicle.

I did find a string on here where a gentleman has the same issue on a 2003. His name is Nicholas Stafford and posted on 05/16/2019.
His diagnosis is it is the CENTER DIFFERENTIAL ASSEMBLY and has a link to the part for his vehicle. I'm going to go that route and change it!

 

[Inspector]

Clunking while turning tight corners (even after changing CV's) screams a center differential problem. I know with the manual transmissions the center diff works a differently than the AT versions. In AT's, it uses an electronically actuated clutch pack to send power to the rear. with MT's, it's all mechanically done. Since the differentials are so expensive, you may want to be absolutely sure you have the correct diff fluid in it.

 

[karlaudi]

Shifts good except it began to not mesh going from 4th to 5th without the clutch...synchro issue or not use to it, just not enough driving by me. It is my GF's vehicle.

Sounds like your transmission is due for a overhaul. What exactly do you mean by, "... began to not mesh going from 4th to 5th without the clutch..."?

 

[Inspector]

I think he means he normally murders his syncros during shifts and the 5th gear syncro is finally giving out

 

[Strobie]

Hey now......I don't "murder" the synchros. It is my girlfriends vehicle, this was probably the 5th time I drove the vehicle after we bought it.
Any manual transmission with synchros can be driven w/o depressing the clutch if you gingerly up-shift (or even down shift) if you don't have a heavy load on the gears, if you have ever driven a large truck like a semi tractor or a dump truck you would know how it's done. Clutches are for starting out and stopping, unless you slam the gears.
Every manual transmission I have had I have driven, on occasion, like this. It is a good way to check the synchros. It worked perfect when cold but after about 10 miles, and the transmission was warned up, it didn't just drop in on the first attempt this one time I tried it....it might have been my unfamiliarity with driving the vehicle.

So what am I going to do? After research, lots and lots of research, I have decided to have the Center Differential Assembly changed. I will update the Forum after the job is complete.

 

[Inspector]

Sounds good, I hope that solves the problem during turns.

Yep, I have a manual car parked in the garage now. Shifting with the clutch engaged increases syncro wear. Why? Because its pretty tough to exactly match everything up, at the correct time, even if your ginger about it....and when you leave the clutch engaged, the syncro will need to battle the rotational momentum of the engine which just blows through the syncro wear material. When you have the clutch disengaged, the syncro is just syncronizing the input shaft.

Best thing you can do for your syncros is double clutch (usually in a downshift), which spins up or down the input shaft as needed so the syncro doesn't need to work as hard.

just my 2 cents

 

[adrian.t]

It's now 2020 and no update to this thread so I'll add my own experience of a few weeks sho (which is why I was looking at this thread). Exactly the same symptom of heavy thud on turning. 2010 Forester with 210,000 km on the clock. The noise came from the transfer case all right but only diagnosed after the emergenence of a high-pitched growl, related only to road speed, which turned out to be broken teeth on the output shafts, caused by a circlip (looks like a clock spring) unwinding into the gears - I'll try to attach photos. The cause has been attributed by mechanics, including the dealership's, to old age. The vehicle now has gearbox which has done "only" 122,000 km.
So, an uncommon fault, especially in post-2008 vehicles, but not unheard of.