Overfilled front diff fluid? 06 subaru forester

[ToothPick]

Hello guys,

My mother took her 06 Subaru Forester to one of those disgusting quick oil change places, and it appears as if they overfilled the front differential fluid. The fluid was past the top fill mark.

My questions are, how bad is this? Is it very urgent to fix? What would happen if I were to let it stay that way?

Also, I heard that the rear differential is "impossible" to overfill due to its design, and due to the top having a hole or something. Any truth to this?

They probably overfilled the rear too, if thats possible.

 

[01rangerxl]

To really severely overfill the diff, they would have to tilt the fill hole up by parking the car facing down on a steep incline.

On vehicles that have solid axles where the tubes need to be filled with oil, filling up to the fill hole is correct. On independent suspension vehicles where the axles are outside of the differential housing, they can get away with a lower fluid level, which helps fuel economy.

Take for example Ford Explorers...with the solid 8.8 you fill to the top of the fill hole on the front of the diff housing. On the independent suspension 8.8s, you fill to a lower level and there is a lower fill plug on the back cover. Same basic ring and pinion, but different fluid levels.

I think the only thing you might notice is slightly lower fuel economy. I wouldn't worry too much about it. Differentials are vented, so being a little overfull isn't going to do anything.

 

[gathermewool]

How far past, and did you check hot or cold?

You can't overfill the rear. There's a drain plug, and above that a fill plug. You literally fill through the fill hole until oil comes out. When oil begins to drain from the fill hole, install the plug, at which point the oil is at the bottom of the fill hole.

 

[joaks]

You CAN overfill the front. How far? You can just let some out, of course.

 

[KenO]

Chances are they put engine oil in that front diff instead of in the engine. Take it to the dealer and get it changed and checked out and make sure no other fluids are contaminated, or empty. Then take the bill back to the quick lube place. Do NOT trust them to fix it on their own! I saw this ALL THE TIME when I worked at the Subaru dealer. That, or they'd dump the front diff drain plug thinking it was the engine drain plug and put 5 more quarts in the engine....

 

[ToothPick]

The front differential is the overfilled one. I thought they probably overfilled the rear as well, but now realize that it is hard to do.

The front diff fluid level was checked cold, or possibly a little bit warm (drove it for 5seconds into the garage from the driveway. The car was also driven for half an hour on the highway a few hours prior to this).

The level was way past the F mark, and went all the way until the dip stick stopped being flat, and turned into the cylindrical shaped part. The level stopped after a distance that I think was equal to the distance between the minimum and maximum level indicators.

The fluid smelled different than the oil. Smelled a bit more nasty.

I would let some out, but I don't know if I have the right tools for the job. I would try to siphon some out, but my siphon tube/pump/container is dirty with engine oil from a different car, and possibly too thick to fit in there.

The "user manual" also does not provide any torque specs for anything other than the wheel lug nuts! And even then, it gives me a range that is 20 ft lbs apart, and tells me to go ahead and put it anywhere between that. Worst "manual" EVER! I will have to do some research to find how hard to torque oil pan nut, differential nuts, etc.

Since I've no torque specs or the tools, I will have a dealer do the job. There is a recall for them to fix anyway.

Back to original question: How urgent is this? Is it as bad as overfilling an engine, which would cause extra pressure, which could blow a gasket? Is it safe to drive like this for a few weeks more?

Thanks for the replies so far.

 

[MolaKule]

Quote:
The level was way past the F mark, and went all the way until the dip stick stopped being flat, and turned into the cylindrical shaped part. The level stopped after a distance that I think was equal to the distance between the minimum and maximum level indicators.



Are you speaking about a differential or a transaxle, or automatic transmisson?

 

[01rangerxl]

I was thinking of front diffs like you find in pickups and traditional SUVs where the differential is a separate component connected to the trans via a driveshaft...then you said dipstick. Are the front diff and transmission an integrated component on this car? If so, fluid level is probably much more important than a regular diff that's housed by itself. In a combined transaxle/diff setup, I'd get rid of the excess fluid, especially since it's way past full.

Wal-Marts and most parts stores sell a small siphon pump for a few dollars that should work. It has two clear hoses coming off of a squeeze pump and the hoses can be routed into tight spaces.

 

[KenO]

Originally Posted By: 01rangerxl
I was thinking of front diffs like you find in pickups and traditional SUVs where the differential is a separate component connected to the trans via a driveshaft...then you said dipstick. Are the front diff and transmission an integrated component on this car? If so, fluid level is probably much more important than a regular diff that's housed by itself. In a combined transaxle/diff setup, I'd get rid of the excess fluid, especially since it's way past full.

Wal-Marts and most parts stores sell a small siphon pump for a few dollars that should work. It has two clear hoses coming off of a squeeze pump and the hoses can be routed into tight spaces.

On a manual transmission Subaru, the front diff is integrated into the transmission. On an auto trans Subaru, the front diff is attached to the front of the transmission, between the engine & transmission. There is a drain plug on the front diff, as well as a dip stick. As I said, it sounds like they more than likely put 5 quarts of engine oil in it, and it's really not uncommon for idiots in the quick-lube places to do this.

 

[gathermewool]

He said the diff oil smelled nasty. Not every diff oil smells nasty, but most do, and it's very obvious.

I'd take it back to the same quick lube and have them drain and refill to the proper spec, AND refund your money. If they say no, don't make a big stink about it. Take the coupon for a free oil change they're likely to give you and move on with your life. It's not that big of a deal.