2003 Subaru outback - We run studded snows and have never had issues with snow/snow packed roads/ice, even on steep mtn roads here in Colorado. We were driving car earlier this week and on an slight uphill snowpacked road the car would “float” in the lane - just move back and forth in the lane, steering corrections would make it worse. My in-law was driving behind and saw the car floating back and forth across the lane. Slowed down, turned back onto wet roads - drove ok. Even driving downhill on snowpacked roads was ok. Took it to the mechanic - new tie rods, new strut supports. New snow tires (not studded this time since we moved out of the mountains). Drove it today - still getting a “floating” sensation even on flat roads that are snow packed. Axles were noted by mechanic as still in decent shape. No other major items identified by mechanic. This float is not normal - we’ve driven this car for 10 years on crazy snowy/icy/steep mtn roads and flat roads alike and have never experienced this. Thoughts?
Update - had to wait a day to get alignment for new tires - alignment was out on all 15 parameters for this car. 11 of 15 have been corrected (last 4 on rear end require much more work, not a safety issue, the values are not terribly off, but will cause slightly higher wear on tires on inner tread which we will keep an eye on and rotate tires and/or flip seating, and “float” is gone). Thank you to all - you were spot on! Great site for feedback and information - we really appreciate the input.
Alignment ? Maybe check the differential fluid as it seems to do it under acceleration. At some point I would take it to a dealer familiar with Subarus.
Floating is generally due to neutral or slight toe out. Does the front or rear tend to float? We set up our rally cars with a bit of toe out to get them to loosen up on gravel surfaces. I would start there. If in spec then the expensive diff inspections comes into play.
There were times in our Subaru when the rear would kick out when going up hill or accelerating as does in our RAV when there is a sudden shift of power to the rear. But, it was consistent. If too much power is going to the rear most of the time and it is loosing traction in snow, it may have to be looked at by someone very familiar with their drive train…like, hopefully a dealer.
Perhaps the drive force to the rear wheels is more than the front drive force is. This would be opposite what it should be normally I believe. If that is the case then the drivetrain system needs to be checked out. I am going to assume that something isn’t happening to the brake system to cause this issue. If there is a problem with the brake system I would think the effected wheel rims would be very warm due to the friction of the brake pads.
I have heard folks complain of this about certain Subaru’s. They have so many different drivetrain/AWD combinations I cannot recall which but recall Outback. My 2005 Manual transmission Legacy Wagon (closely related) with Limited Slip rear does not do such a thing.
I agree with @rallyace, check the alignment, the toe may be off in the front, rear or both. I would have pointed at the tires but you changed them and the problem still exists. Some tires are more sensitive to toe settings than others but a little toe in (within spec, of course) should settle the car down.
Post the alignment readings if you can. You should have them on a printout that was returned to you with your copy of the shop order.
Many vehicles today cannot be aligned in the “leaning” (camber) axis without special kits that include eccentric bolts. I don’t know if yours is one, and no longer have access to databases, but the readings will tell.
Is this one of the models where you can remove a fuse to disable AWD? If so, maybe you could try that as an experiment and see if the problem still occurs.
^
Lion9car has a good suggestion, but…the Subarus that allow you to defeat the AWD feature require that you INSERT a fuse into a special fuse holder on the top of the strut tower on the passenger side of the vehicle.
If the OP’s Subaru is one that has this feature, it will be noted in the Owner’s Manual, along with instructions on where to find the appropriate spare fuse, and where to insert it. However, if the OP is lucky enough to have a six-cylinder Outback, it has a more advanced AWD system that cannot be defeated by inserting a fuse.
And the alignment problem would change from going up hill and make a car float dramatically to the point of nearly being out of control on snow and suddenly not if the terrain changed or no snow. How is that ?
Update - had to wait a day to get alignment for new tires - alignment was out on all 15 parameters for this car. 11 of 15 have been corrected (last 4 on rear end require much more work, not a safety issue, the values are not terribly off, but will cause slightly higher wear on tires on inner tread which we will keep an eye on and rotate tires and/or flip seating, and “float” is gone). Thank you to all - you were spot on! Great site for feedback and information - we really appreciate the input.