Any Risks when driving in FWD only?

[DooMeSuuby]

Hello,

 

Due to torque bind ('97 Legacy GT) I have inserted the 20 amp fuse and am now driving in FWD only.

 

Is there any risk associated with leaving the car in FWD?

 

I've followed the great suggestions from many people about how to deal with torque bind. Here are my findings:

 

1) Identical tires, pressure at 35 psi, have reduced the "shudder" by 50%.

 

2) When I take out the fuse and drive in AWD, the shudder appears during turns at slow speeds, especially left turns.

 

My next step is to refill the front and rear Differential Fluids - but I don't know how to do it and there is no article in the "Repair Manual" section of our website.

 

Any comments, feedback will be much appreciated. Thank you!

 

David

[yarikoptic]

well.. I'm not sure if differential oil is what you need to change... it seems that most people are talking about flushing AT fluid while trying to fix binding. power flush of AT is quite expensive. As for change of differential oil - that darn simple - drain from the bottom, fill in from top :-) As for back differential - the only note is first to make sure that you can take of top bolt so you can measure the level, otherwise if you drain it and then discover that you can't fill it in now - sad experience

 

For me it was enough to change tires + change AT fluid and front differential oil (just because I was doing all this crap)

 

besides that - try to do some 8s in the reverse on some parking deck - it might brake your binding.

[The Dude]

If by "risks" you mean mechanical damage to your car, then the answer is probably no. Obviously, the car will handle differently in FWD mode.

Generally binding is caused by a worn out clutch pack.

[mattocs]

If by "risks" you mean mechanical damage to your car, then the answer is probably no. Obviously, the car will handle differently in FWD mode.

Generally binding is caused by a worn out clutch pack.

 

Do a search. There are risks...but if it is only going to be for a while until it is fixed, then everything should be fine. You can wear out your Duty C Solenoid or something like that.

[The Dude]

Do a search. There are risks...but if it is only going to be for a while until it is fixed, then everything should be fine. You can wear out your Duty C Solenoid or something like that.

 

If power was removed from the duty c soleniod the clutch pack would be fully engaged. In other words, the default state of the clutch pack is fully engaged. The normal operating condition for the 4EAT transmission is 10% drive to the rear wheels. Therefore, the duty c soleniod is ALWAYS energized. The FWD fuse merely fully energizes the duty c soleniod so that the clutch pack is fully disengaged. I would doubt that the transmission or associated components would be subjected to additional wear from being placed in the FWD mode.

[kevinsUBARU]

changing the front and rear differential fluids is a cakewalk...I will try to describe in depth soon if someone doesn't beat me to it.

 

Kevin

[sregor13]

I have seen this discussed before and I am also expereince the same thing in my 90 Loyale. First of, I think most agree it will not damage the Tranny to Drive in the FWD Mode. Period. Second I dont think changing fluid will do you any good. i would stick to the Duty Solenoid concept. Search for "Binding" or Solenoid C and you should find out a little more about this. Mine is believe to be an electrical problem more than anything else. But I think I remeber someone saying there a two simple things to change and check in the tranny and if it isn't one of those things then you might need a new tranny. One of those is the solenoid.

[DooMeSuuby]

Thanks folks.

 

To: "The Dude" - I have seen several of your posts and you are always so articulate... thanks for sharing your expertise. I'm sure you've helped tons of people.

 

To: "kevinsUBARU" - Yes, I would love a clear description of how to change the Tranny fluid and also the differential fluids.... thank you for offering.

 

I'm looking forward to this problem disapppearing, and reporting the results to the community!

 

David

[Al_SemC]

SOA says that it's only for short distances and low speeds. 30MPH, max of 30mi. After that, it starts to get broken. I don't know why, but I do know that there's no benifit to the company to say that, so I'm inclined to believe them.

[The Dude]

SOA says that it's only for short distances and low speeds. 30MPH, max of 30mi. After that, it starts to get broken. I don't know why, but I do know that there's no benifit to the company to say that, so I'm inclined to believe them.

 

 

I'n not saying that you are wrong, but could you cite the source for your information? Your information sounds suspeciously close to the OLD Subaru recommendation that an AWD AT could be towed with all four wheels on the ground for a maximum distance of 31 miles at a maximum speed of 20 mph. Subaru NOW recommends that AWD AT cars be towed with all four wheels off the ground ONLY, as on a flat bed towing truck. Make it easy on yourself, if you own a Subaru AWD with an AT insist on a flat bed towing truck everytime.

[friendly_jacek]

I'n not saying that you are wrong, but could cite the source for your information? Your information sounds suspeciously close to the OLD Subaru recommendation that an AWD AT could be towed with all four wheels on the ground for a maximum distance of 31 miles at a maximum speed of 20 mph. Subaru NOW recommends that AWD AT cars be towed with all four wheels off the ground ONLY, as on a flat bed towing truck. Make it easy on yourself, if you own a Subaru AWD with an AT insist on a flat bed towing truck everytime.

 

Second on the articulate part :-)

[Al_SemC]

I'n not saying that you are wrong, but could you cite the source for your information? Your information sounds suspeciously close to the OLD Subaru recommendation that an AWD AT could be towed with all four wheels on the ground for a maximum distance of 31 miles at a maximum speed of 20 mph. Subaru NOW recommends that AWD AT cars be towed with all four wheels off the ground ONLY, as on a flat bed towing truck. Make it easy on yourself, if you own a Subaru AWD with an AT insist on a flat bed towing truck everytime.

 

The speed and time I don't recall where I got, but I do know that my manual says "For short distances and at low speeds, for emergency situations and when you must use the spare tire" or somesuch. So, I cite that as my source. I can get it for you verbatim when I get get back to where the book is on Sunday night.

[sregor13]

I was finally able to find the Earlier thread on this Subject with seemingly undispusted proof that driving in FWD wont damage your Tranny. I also think this would be a good one for you as it does go into the Binding Issue. The thread is called AWD into FWD only? and there are about 30 replies to it.

[DooMeSuuby]

Thanks, the SOA citation now seems critical.

 

I've been operating the vehicle at high speeds for 7-8 days now.

 

Last week, I went into the Marin, CA dealership and (in between caviar niblets)one mechanic managed to say there is no problem running in FWD.

However, I am not confident in their level of expertise at that dealership.

 

Also, any pointers to where I can find clear directions on how to change the AT fluid, front diff. and read diff. fluids, I will be very grateful.

 

Thanks again,

 

David

[Al_SemC]

Thanks, the SOA citation now seems critical.

 

I've been operating the vehicle at high speeds for 7-8 days now.

 

Last week, I went into the Marin, CA dealership and (in between caviar niblets)one mechanic managed to say there is no problem running in FWD.

However, I am not confident in their level of expertise at that dealership.

 

Also, any pointers to where I can find clear directions on how to change the AT fluid, front diff. and read diff. fluids, I will be very grateful.

 

Thanks again,

 

David

 

Oh, I can tell you that. Remember to always do these on a level surface.

 

AT Fluid - The simple answer is that you can't change it. Not all of it, anyway. About four of the ten quarts is stuck in the torque converter all the time. Many people find that they are comfortable with mostly new fluid. You change it by:

 

- Jack up the front of the car enough to get underneath.

- Put something under the tranny pan to catch the fluid.

- Take out the pan drain plug. It's on the bottom of the pan. It looks much like the oil pan drain plug. The fluid will drain out.

- Wait until it stops flowing, then clean the plug and put it back in. Tighten it down so it's snug, but not so tight that you can't get it off. I think 30ft*lbs is the right number, but don't quote me.

- Put the car back down.

- Get one of those skinny funnels, take out the tranny dipstick and stick the funnel in the tube.

- Pour in four quarts of fluid.

- Start the car, put the shifter in each position for a couple seconds, then put it in park. Leave it running.

- Use the dipstick to check the level of the fluid. If it's in the "COLD" range, you might be done. If it's low, slowly add fluid until it comes up into the cold range.

- Take a drive, long enough to heat up the tranny. This is a drive of 10-20mi long.

- Check the level of the fluid again. It should be in the "HOT" range. If it's not, add a little more fluid until it's in range.

- Over the next few trips, check the fluid level to make sure it's still right. Also listen for new, strange noises and such.

 

This will get you 60% new fluid. Alot of people I know just repeat the process and are left with about 80% new fluid. Alternatively, you can take it someplace and have them do a real power flush. AAMCO does it. It's usually like $100.

 

Front Diff Oil -

- Jack up the car again.

- Get your pan back out.

- Remove the diff drain plug. It's off to one side, as I recall. There's only two plugs, so you should be able to find it. It's the one that's not on the pan. The gear oil should come out. Yes, I know it stinks. It's supposed to.

- Clean the plug and put it back in.

- Put the car back down.

- Take out the diff dipstick and put new fluid in through the hole. It takes 0.8qt, as I recall. 80W90 oil, I think. Check your manual. It comes in a squeeze bottle, so you shouldn't have trouble getting it in.

- Use the dipstick to check the level. Add more until it's around the "FULL" mark.

- Put the stick back in.

- Test drive and listen for odd noises.

 

Rear Diff Oil -

- One again, jack up the car, but this time, the back.

- Get out your pan again.

- Use either a plug wrench, a breaker bar or a socket wrench to take out the bottom plug on the back of the rear diff. You'll need a 1/2" drive. Just stick the square end in the hole.

- The oil will drain out the bottom hole into the pan.

- Put the plug back in.

- Remove the top plug.

- Put new gear oil in through the top hole until it reaches the bottom of the top hole. It takes somewhere around a quart. Alternatively, squirt it in until it starts coming out the top hole. You'll probably have trouble doing this since it's close to the floorpan in the car and the swaybar's in the way. Many people get an inexpensive hand pump from a parts store to do it.

- Put the top plug back in.

- Make sure both plugs are tight.

- Test drive and listen for odd noises and such.

 

Enjoy.

[Olnick]

Just a point of common sense to the above instructions regarding the rear differential: Remove the TOP plug first. Think about it--what if you removed the bottom plug, drained all the oil out and then couldn't loosen the top plug?

You'd be up a creek!

[The Dude]

If you do not already have a copy, buy the Haynes Subaru Legacy Service Manual. This manual gives detailed instructions on changing the fluids in your car. I have found the Haynes manual to be an invaluable resource, I recommend it highly. Unfortunately, it is unlikely that changing the fluids in your car will resolve the binding issue. It is probable the clutch pack in your car has become worn. The clutch pack usually becomes prematurely worn as the result of running non-matching tires on the car. Subaru's specs for tire matching are VERY, VERY tight.

 

I believe that a clutch pack replacement should run under one thousand dollars. My car has 175,000 miles, and I live in almost snow-free South Carolina. Would I pay to replace the clutch pack, or would I just put the AWD fuse in and continue to run the car until the wheels fall off? It's a toss up.

[sasquatch]

you risk getting batter gas mileage

[friendly_jacek]

you risk getting batter gas mileage

 

It's a myth.

Did you test it yourself?

I did and there was no difference in MPG.

[friendly_jacek]

Unfortunately, it is unlikely that changing the fluids in your car will resolve the binding issue.

 

Well, if you do a search here, you find that it did help many people.

It makes sense, if fluids are neglected and dirty, particles in the fluid will make the clutch sticking.

One vote for articulated and one vote for opinionated.

[sasquatch]

It's a myth.

Did you test it yourself?

I did and there was no difference in MPG.

 

First of all, I said RISK. I wasn't offering any scientific test and secondly I'd be hard pressed to believe you wouldn't get better gas mileage.

[The Dude]

Well, if you do a search here, you find that it did help many people.

It makes sense, if fluids are neglected and dirty, particles in the fluid will make the clutch sticking.

One vote for articulated and one vote for opinionated.

 

 

First off, nothing would please me more than if DoMeSuuby was able to resolve this problem with nothing more than a fluid change. I do not own common stock in Fuji Heavy Industries, and I am therefore indifferent to the dollar amount of automotive repair parts sold by Subaru of America.

 

"Unlikely" means less than half. And yes, I believe there is a less than a 50% chance that any given car beset with torque binding will become fully operational solely by changing the fluids.

 

It is clear that the most frequent cause of torque binding is mismatched tires on the car. The first step in trying to solve the problem would be to check the tires. If I remember correctly, they must not differ in circumference more than 1/4".

 

The clutch pack is located in the tail section of the AT. If changing a fluid is going to fix the torque binding, then the AT fluid alone should do it.

 

There is another possibility of which I am admittedly uncertain. I believe the the AT aluminum tail shaft housing on earlier model Subarus would wear prematurely and cause binding. I am not certain what MY the aluminum tail shaft housing was replaced with one made with steel.

[schspeedster]

My guess as to why there isn't a FWD/AWD switch on the dash: Uneven tire wear.

 

If AWD was enabled only for snow, and tires were not rotated, the tires would then differ in size. Subaru AWD would get an undeserved reputation as unreliable junk that binds up and needs expensive repairs. This would explain why the owner's manual doesn't encourage leaving the fuse installed.

 

Got my Legacy with front tires more worn than rears. Felt something binding up, which went away with FWD fuse installed. Is it possible to measure a pair of replacement tires in the tire shop to match, or will I be buying a set of 4?

 

I can now appreciate AWD isn't just for snow, after installing the fuse, pulling out of a parking lot with loose gravel onto a main road into traffic, and spinning the front tires.

[DooMeSuuby]

Hi everyone.

 

The mechanic who looked at my fluids said they appeared to be clean and in good shape.

 

Given that the Torque Bind condition occurred immediately (within a day) after I put on the mis-matched tires in the rear, and given that I drove the car like that for two days, some freeway, I'm reluctantly assuming that the clutch pack has been damaged.

 

I'm going to go for a full AT flush at a shop (rather than do it myself, as per Al's great directions... thank you again!) in the hope that perhaps there is some particulate matter in the AT fluid.

 

Also, given the fact that I'm now running all 4 identical tires and that _reduced_ the Torque Bind syptom to occur during TURNS ONLY, what do you think my chances are, of the AT Fluid power flush correcting the condition?

 

Thanks everyone!

 

David

[DooMeSuuby]

OK.... here are results, and an IMPORTANT question.

 

To deal with Torque Bind symptoms, I did the following:

1) All four tires same make/model

2) Tires at 35 psi

3) Complete ATF flush/fill. ($145.00)

 

Torque Bind is reduced by 90%. Great news.

 

QUESTION:

The mechanic who did the ATF flush/fill says: 'Yes, the Torque Bind is still there... DRIVE IT for 1,000 miles - 2,000 miles in AWD.. you CAN'T HURT anything, and you may just loosen up that clutch pack."

 

Can someone corraborate, please? Does he mean i can't hurt anything because the tires are now all the same?

 

Thanks PEOPLE I'm almost out of the woods!

 

david

 

 

 

 

 

 

 

Hi everyone.

 

The mechanic who looked at my fluids said they appeared to be clean and in good shape.

 

Given that the Torque Bind condition occurred immediately (within a day) after I put on the mis-matched tires in the rear, and given that I drove the car like that for two days, some freeway, I'm reluctantly assuming that the clutch pack has been damaged.

 

I'm going to go for a full AT flush at a shop (rather than do it myself, as per Al's great directions... thank you again!) in the hope that perhaps there is some particulate matter in the AT fluid.

 

Also, given the fact that I'm now running all 4 identical tires and that _reduced_ the Torque Bind syptom to occur during TURNS ONLY, what do you think my chances are, of the AT Fluid power flush correcting the condition?

 

Thanks everyone!

 

David