So how do you disable the rear drive again...

My 96 Legacy Outback with all wheel drive is still making the shuddering even after two transmission drain and refills. My front and rear tires are different brands but the same size. I haven't measured their exact circumference to see if the shuddering is caused by the unequal diameters. I've read where there is a fuse that you install to disable the center diff. What and where might that fuse be?

 

Thanks for any help.

 

BTW Brokendarkagain, are you here yet?

 

Tom

You can take any of the fuses out of the fuse/solenoid box by the driver side fender and place it into the FWD fuse holder. This is located by the passenger side towards the firewall. It says FWD on it.

 

It is not recommended that you drive the car in this mode for very long as as it may damage the Duty-C. In your case, though, it may already be damaged.

May be your driveshaft....

the fuse is only for the auto trans cars, so do that if it applies to you.

 

the other thing you can do if you have 2 matching pairs of tires, put one matching pair on the driver side and the other matching pair on the passenger side. this will make the average front axle speed the same as the average rear axle speed.

 

try it and see.

"the fuse is only for the auto trans cars, so do that if it applies to you" good point !

... changing tires around will not really help much, on the owners manual they recomend you not to have mismatch tires ..having mismatch tires will make the spider gears (located in rear/front/center differential ) to rotate at different speeds, over time they generate more wear and unequal heat.

 

if you have an auto trans, they usually have two dipsticks , one for the front differential and one for the trans fluid ... which one did you flush.

 

do a visual inspection on the rear diff, make sure that it has no leaks, check for proper level. etc..

Changed trannie fluid, front diff oil and rear diff oil.

 

Put a 10 amp fuse in that little holder and the shuddering went away. Took it out and it came back. Also noticed that the high frequency vibration that I've been experiencing is diminished with the fuse in.

 

Tom

Well, now this is interesting. I'm getting 25 mpg with just fwd, BUT the speedometer needle is fluctuating wildly at low speed (8mph or less). After about 10 it settles down. I took the fuse back out and see if that is the cause of the flucuations.

 

Tom

speedo fluctuations is usually the front VSS, speed sensor.

 

if the problem goes away with the fuse in then it is probably the tires, since you do not have a flashing AT Temp light at start up. rotate the tires so one matched pair is on one side of the car and the other matched pair is on the other side of the car. then try driving with the FUSE OUT. this will tell you if it is the tires or some mechanical problem in the transfer clutch rear extension housing on the trans.

 

you cannot drive forever with the fuse in, you may as well move the tires from front/rear to left/right and see if it makes a difference.

 

if you don't want to move the tires but do want a more simple answer try this; buy a new set of 4 matching tires.

 

report back when done.

Speed sensor, or something within that system isn't working properly. This could also explain the torque bind. If the speed sensor(s) is/are reading wrong, the center differential would be adjusting itself to the wrong inputs.

 

Same thing happens on my car whether it is in FWD mode or not. I have a torque binding problem as well but it is intermittent. The speedometer tripping out is also intermittent.

 

EDIT: GAH John! you beat me to the punch... But you're info is much more specific

typically when the speed sensor fails, you also lose AWD. (if the system cannot compare front speed to rear speed it defaults to FWD). it does not usually cause torque bind, at least i have not seen it.

 

rotate or buy new tires and replace the speed sensor.

I knew that when the speed sensor fails it reverts to FWD, but I would think that it could be reading wrong or the TCU could be confused or reading the info from the speed sensor wrong.. Is this possible? Because if it was reading wrong, even intermittently, and the TCU read the speeds differently from what the actual speed difference between front and rear is during cornering, couldn't that cause some binding?

Well, since all four tires look brand new, I decided to remove the rear driveshaft and pull the fuse. Is there a seal around the pinion nut? Because a small amount of gear oil came out when I pulled the drive shaft off of the pinion flange. I can see that there is a seal between the pinion shaft and the differential housing and that isn't leaking at all.

 

Drives nicer and is peppy-er in 2WD mode. I'll leave it this way untill I wear out the tires then buy 4 new ones and replace the drive shaft. I think I will machine a piece of 1/4" aluminum and make a block-off plate.

 

Tom

Drove it about 100 miles today and then put it up on the lift. Absolutely bone dry inside that pocket where the pinion nut resides. Don't know how that gear oil got in there in the first place, but it doesn't look like a bad seal. I'll still make a block off plate.

 

Also found one of the sources of knocking from the rear of the car. Both sway bar end links are shot. That'll be an easy fix.

 

Tom

Bringing this back from the near dead to report that I pulled out the VSS and took a look at it. Spun the blade a few times and could feel the magnetic pulsing as I rotated it. Cleaned the old sealant off the threads, added a little new sealant and re-installed, being careful to make sure the blade dropped into the slot below before I started the threading down of the sensor.

 

Also drained the ATF for the third time; and this time it was much darker than the first two times. I don't think I left the first re-fills in there long enough.

 

Took it out for a test drive and not only is the bouncing speedometer action gone, but it doesn't have that delayed 2-3 shift anymore. Woohoo!

 

Next up is to replace the rear driveshaft and see if this has cleared up the low speed shuddering.

 

Also went junkyarding with John (Brokeindarkagain) for his new 5 speed tranny and while there I picked up a front bumper cover that isn't all beat up. Got a few of the dealer plastic retainer pins for the top; boy are those expensive. Thankfully, he didn't show any clips for the bottom so I will go to Ford where I can buy a12 pack for the same price as one from Subie stealership.

 

Thanks for all the help guys.

 

Tom

2.23 apiece!

 

Tom

I've been searching some and wondered if it's possible to remove the driveshaft altogether, use the proper fuse and run the transaxle in FWD mode permanently?

 

This is for a project which will be using a 1997 Legacy engine and 4EAT.

Were Legacy's even available in FWD only or just AWD?

Were any Subaru available in the US not AWD?

wondered if it's possible to remove the driveshaft altogether, use the proper fuse and run the transaxle in FWD mode permanently?

 

there are 2 ways to make an AWD car FWD,

 

1/ remove the REAR section of the drive shaft.

the front section needs to remain or ATF will spill out.

 

2/ insert the fuse in the FWD fuse holder.

 

these only work for auto trans cars.

 

however if you want a FWD trans,

serach for a legacy 90 - 97 FWD trans at :

http://www.car-part.com

sort by zip code.

if you have to ship, ~150$,

sort by price.

Thanks for the info, I'll check the site out.

I'm looking for a donor car for this project and the only option I have on the Kelly Blue Book or NADA website is for AWD. There isn't an option for FWD for '97 Legacy.

Are the FWD trans at car-part from another country?

From the looks of an automatic transmission diagram, if the rear driveshaft was removed and the fuse left out it should still run fine with the rear output capped off somehow to prevent ATF from leaving and/or mung and drool from entering.

I'm looking for a donor car for this project and the only option I have on the Kelly Blue Book or NADA website is for AWD. There isn't an option for FWD for '97 Legacy.

 

if you search the car-part site for a 97 auto trans in a legacy it should ask AWD vs. FWD.

but that may only be computer info, not real world,

meaning the FWD was available, but they did not sell any ,

or not many.

 

but there is no reason to focus on 97.

 

the legacy went OBD2 in 95,

and 95 - 96 ej22 are non-interference engines.

so either year FWD would give you a great combination for a project.

 

i'm pretty sure the same is true for the impreza.

and the impreza may have more FWD cars.

it cost less than the legacy and the FWD cost even less.

 

but suabru made FWD cars, legos 90 - 97,

and imprezas 93 - 97.

if you do not care about OBD2 look at pre-95 cars.

 

if you are pulling the parts for a trans plant,

look at the impreza as well.