Outback slack or play in drive train?

[wekjo]

2002 Outback 2.5 manual transmission, 139,000 miles. What i have is a noticeable play in the drivetrain. This is most annoying and evident when going down long slight grade hills at freeway speed. Cruise control lets off and you lean forward in your seat, you slow down a bit cruise kicks back on and it snaps you back. I have had this car since it rolled over the 100,000 mile mark and it has been the same. No other car I have owned, and they have just about all been manual shifts, ever did this. I have changed the clutch, and both front drive half shafts to no avail. What I am looking for are some simple checks to rule out the transmission, the front or rear differentials, or the coupling. Some mechanical part is taking a beating and I would like to replace it before it fails at the worst possible time and place. I suspect it is the transmission as the effect is more noticeable as you get into higher numbered gears. It does not grind, vibrate, or grab whilst making sharp slow turns. Problem is just as noticeable with cruise control turned off. If anyone has had this problem and it was the transmission, is there anywhere to send it off exchange for a rebuild.

[987687]

The number one thing that causes this is probably the trailing arm bushings. It's insane what a different they make. After that, it's your engine and transmission mounts getting tired.

[Fairtax4me]

^ What ^ said ^

Trailing arm bushings. Mine are shot and the whole car jerks around if I get on or off the gas wrong. Also lets the rear wheels "walk" around and make the car handle strange.

 

Don't lift the car to check them. They are loaded when the wheel droops, put a prybar or big screwdriver in front of the bushing with the wheel on the ground and see how far you can move it. It helps to leave the parking brake off.

[wekjo]

Thanks for your thoughts. I took the car to the shop which replaced my head gaskets, seem to know what they are doing. They put it up on a lift which

held the car up by its wheels, not the frame. They poked, prodded, twisted and levered around everywhere and found no mounts nor bushings which exhibit anything

but minimal wear. Given the price of labor to drop the rear end down press the bushings out and replace them and reassemble it, they declined to do the work as they

felt whatever the problem is, replacing those bushings would not be the right fix. I looked on youtube, saw a number of subaru trailing arm bushing videos but those

trailing arms and bushings are quite different than those on my Outback.  Those entire trailing arms can be purchased new for less than 80 dollars and looks like an owner

with hand tools and jack stands could replace them in his driveway. The trailing arms in my car cost over $200 each and are much more labor and tool intensive. The drive shaft

passes through it.

 

So are there any other thoughts or tests to exclude the coupling or the transmission? Watching those guys wrassle the shafts around under my car makes me believe that

neither the front nor the rear differential is the culprit, nor any of the CV joints.

[987687]

You're probably looking at videos of 1999 and earlier outbacks. In 2000 they completely 100% changed the rear design. In the older ones, yes, you can swap the trailing arm out with two bolts in your driveway.

With your 2002, the trailing arm, knuckle, and lateral links are essentially conglomerated into one massive arm that sucks to work on.

 

But the shop is wrong to an extent, you don't have to pull the arm to change the bushings, you can just drop it at the mount and burn the old bushing out. Saw the bushing sleeve, and hammer it out with a cold chisel. Aftermarket bushings don't have to be pressed in, so you don't have to remove the arm and bring it to a press. Overall it's not a terrible job, and certainly don't have to completely disassemble the suspension.

[Fairtax4me]

The trailing arm bushings can be pressed out with a c-frame press without removing the whole arm from the car. Some specailaty tool companies make sleeve and bolt press kits specifically designed for bushing removal and installation. It's usually not very practical for a DIY'er to own one of those sets because they can be pricey, but a good shop should have one.

If nothing else, you can usually buy two large sockets and a long grade 8 bolt that fits through the center of the bushing to use as a puller.

 

 

I'm not surprised that they found nothing wrong with the trailing arm bushings. They can appear to be just fine even after they've gone "soft". The forces the vehicle exerts on drivetrain parts are much greater than what we can apply by hand, even with pry bars and such.

 

I really don't think ring and pinion or differential wear is an issue or else you would also have noise from those parts. Normal backlash between the ring and pinion gears is something like .008-.012". Any more than that and you get accelerated wear usually with a whining or droning sound while accelerating or decelerating (depending on which side of the gear is worn). This also greatly accelerates wear and the gears would fail within a few thousand miles.

There is a set of support bushings on the back of the rear differential housing that secure it to the rear cross member. I've seen a few posts about those bushings being bad. Those could also cause a jerking or jumping feeling because they allow the rear of the housing to flop around. Might check those as well.

Edited February 23, 2013 by Fairtax4me

[Selum]

These cars have quite a bit of slop in the drive train. If you're used to two-wheel drive cars (particularly FWD), it will take some getting used to.

 

Best wishes,

Myles

[987687]

They shouldn't have play in the driveline... I'm helping my friend build a stage rally car. We've put bushings everywhere and new struts. As soon as you hit the gas the car launches forward. No waiting for the driveline and getting a BANG and it all catches up. But as has been said, trailing arms are the worst offenders.

[wekjo]

Had a couple of country ya-hoos replace the exhaust gaskets on the Y-pipe and the catalytic converter. They diagnosed the cause of the blown out front O2 sensor and gaskets as being a plugged converter. No one had noticed that before and tied it together, including the high buck german car repair shop. Engine was running smooth and not making a vacuum cleaner noise so I guess all of the symptoms were not there.  After rasseling around installing the new direct fit dual converter pipe, they pointed out to me that the carrier bearing was shot and I should think about that too. Well duh! Though I have collected replacements for almost all of the bushings in the rear end, I am going to do new struts, strut mounts, and bushings all at once;  I am going to replace the drive shaft first, which includes a new carrier bearing. Given the obvious run out in that bearing I am going to put my money on that bearing being the cause of my drive-train slop.