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Looking to change front and rear diff fluid on my 1996 impreza brighton


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Front diff is easy. pull the drain plug, and then refill. For an a/t it should be about just more than a quart for the front.

 

Same for the rear, but remove the bottom plug to drain, and the top plug to fill

 

Get 2 bottles of gear oil. Do the rear first. You can squeeze out about half of the first bottle to get it in there. Then squeeze out half the 2nd bottle. Then combine the contents of both bottles to one bottle and use that to fill the front.

 

Let the oil settle in the front as it will stick to the side of the fill tube and be all over the dip stick. Let it sit 5 minutes or so for a more accurate reading.

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Just a note about doing the rear diff. Pull the top plug first. If you pull the bottom one all the oil drains out. Then if you can't get the top one out, you're screwed.

I use a syringe to fill the rear diff.

If it's cold in your part of the world heat your gear oil up inside by your heater for a while first. Gear oil is very thick when it's cold.

Same goes for changing it. Probably a good idea to drive the car 10 miles or so before hand just to get the temp in the diffs up a little bit. The old oil will drain out a lot faster.

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  • 3 weeks later...

What kind of fluid should I put in the diff? I'd prefer to stick with whatever a Subaru dealer would install if you were to go to them. Does friction modifier need to be added too?

 

Thank you to everyone who previously posted.

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Subaru gear oil is fine. I don't want to start any 'oil arguments' but the manual specs GL-5 for the diff and people all have their favs when it comes to that stuff. Dunno if you have a stick or auto - but the stick shares fluid with it's diff and you definitely want to be careful with that fluid - might be only 3-4 appropriate fluids for that - again, lots of 'discussion' there too. Subar Extra-S would be great. Front diff on the auto get the same fluid as the rear diff.

 

I used my floor jack on t the end of my 1/2" breaker bar to bust the rear fill and drain plugs loose - cheater bar should work if you have room to swing it.

 

I bought an inexpensive pump from Amazon to fill the rear diffs. I also bought a funnel with a tube on it to help with the front diffs.

 

As said, take your time when filling, try not to overfill the front diff. The rear you fill until the fluid starts to dribble out the top hole. Can't recall the torque values for putting the plugs back in.

Edited by 1 Lucky Texan
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5-speed manual with 276k on the car. :) I bought a pump from amazon too for the diff fluid change.

 

I am changing the fluid because of two symptoms:

 

1. When backing out of driveway, when I turn the wheel sharply, it seems to 'drag' a little and slows the car down. Only seems to happen when cold in the morning.

 

2. Slight high-pitched vibration during the first 5 miles or so when cold in the morning. Mimicks a u-joint vibration or driveshaft balance vibration.

 

I'm changing the fluid to see if it improves at all...

Edited by kickascii
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5-speed manual with 276k on the car. :) I bought a pump from amazon too for the diff fluid change.

 

I am changing the fluid because of two symptoms:

 

1. When backing out of driveway, when I turn the wheel sharply, it seems to 'drag' a little and slows the car down. Only seems to happen when cold in the morning.

 

2. Slight high-pitched vibration during the first 5 miles or so when cold in the morning. Mimicks a u-joint vibration or driveshaft balance vibration.

 

I'm changing the fluid to see if it improves at all...

 

 

any work done before this started?

 

 

 

Check for a stuck brake caliper while you're under the car. Make certain the axles are seated in the diffs.

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What's the point of that? For the rear diff just use a 1/2" end of a breaker bar or socket. Or some of them are hex head socket. Same goes for the front diff.

 

1/2" = 12.7mm. the drain plug is 13mm. It'll strip if you keep using a regular breaker bar or ratchet. mine certainly did

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1/2" = 12.7mm. the drain plug is 13mm. It'll strip if you keep using a regular breaker bar or ratchet. mine certainly did

 

The drainplug in my GL was so tight that I had to use a jack to push up on my breaker bar. It lifted the back wheels off the ground. I jumped up on the bumper and it finally cracked loose. That's some serious abuse, and it didn't strip...

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  • 2 years later...

I know this is an OLD topic, but I found it and had to relate my experience. If your going to change the rear differential fluid and you have already found the plug frozen this is my best advice. 1) Get the Metric set from Harbor Frieght with the 13mm

socket. I got one for $8 with their coupon. The 1/2 inch driver will work, but I don't recommend it. 2) Many years of breaking hard bolts has taught me patience. Clean the area, treat with penetrating oil, tap gently and heat with propane. This can take awhile, overnight, multiple treatments. Be patient. It's most likely to move when hot and the joint has expanded. 3) Take the top/filler out first, just in case the bottom doesn't move. 4) Best option is an inpact hammer, but a jack and breaker bar can work. 5) The bottom plug has a magnet on it, clean it well. 6) When your ready to fill, heat your oil up in a bucket of HOT water. Get a piece of vinyl tubing, heat the end and force it onto the bottles nipple. The tube allows you to hold the bottle at different angles to almost drain it, 25 ounces will do it. Remember, your under the gas tank, don't go crazy with the propane. Just get it hot, spray with oil while hot and tap, tap, tap. My plugs hadn't been moved in 18 years and it took about three goes at it. Good luck.

Edited by sub96
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