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My 1998 Legacy Outback has recently started shuddering when pulling out from a dead stop but only with the wheels turned to either side. My guess is that this is being caused by the CV joints or knuckle joints on the drive axles. As a result I am planning on replacing the drive axles. Do you agree with this assesment? Thanks for your time.

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Thanks for the tip. I gave it a try and the studdering problem goes away. Now my question is "Why?" If the fuse forces it into front wheel drive why would that eleviate the problem rather than making it more pronounced? Also, how long can I run it in FWD and, of course, what is my next step? New tranny?:slobber:

 

 

 

check out this thread

http://www.ultimatesubaru.org/forum/showthread.php?t=22747

 

If you have an automatic, put a fuse in the FWD fuse holder to see if the problem goes away. If it does, it's transmission related, not cv axle related.

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As cookie mentioned, check your tires. Subaru says that the circumfirence needs to be within 1/4" between all tires.

 

If your tires are ok, then first thing I'd suggest is changing the transmission fluid. Old fluid can sometimes cause contamination or issues with the rear clutch pack. If that doesn't help, you'll most likely need to have the rear clutch pack worked on / rebuilt.

 

The automatic's AWD system is controlled by the trans computer. It has a rear housing with clutch packs in there. A duty solenoid controls line pressure to the clutch packs, which in turn varies how much power goes to the rear wheels. When you put the fuse in, it sends a constant 12v source to that solenoid which pretty much closes it, and sends very little to no power to the rear wheels.

 

It's not a good idea to run too long with the fuse in, because the solenoid is designed to get a pulsed signal from the TCU, rather then a constant signal. So you could prematurely wear out the duty c solenoid.

 

here's scans from the factory manuals of the auto's awd system

 

http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/AWD_transfer_system1.jpg

http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/AWD_transfer_system2.jpg

http://www.main.experiencetherave.com:8080/subaru_manual_scans/FSM_Scans/AWD_transfer_system3.jpg

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the link legacy777 referred to was mine about a week ago... tried the easiest possible solution first- the different diameter tire situation. found tire pressure was different in all four. filled them to similiar psi- no studdering since. hopefully this is it! thanks to all for the advice. mahalo from maui.

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You guys are the BEST! Changed out the tranny fluid and the shuddering disappeared like magic. I haven't checked the tire sizes yet. On that point, am I looking at wheel diameter or circumference? One post mentions diameter and one mentions circumference. Either way I guess I'll be buy tires four at a time now.

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