Gearbox Oil Level Issue

[Bluestone]

The other day, I drained my Sube's gear box and refilled with Red Line 75/90 NS.

It was done on level ground, only lifting the front of the car so I could get at the drain plug, then dropping it back down to drain.....same procedure for refilling.

When draining, I waited 'till the oil barely dripped out before putting the drain plug back in.

Now, the manual says that the gear box capacity is 3.7 quarts(US). At the fourth quart bottle, I used half of it, then checked the fluid level. Well, the dipstick showed the fluid level about 3/8" above the Full mark.

I"ve since checked the level several times after driving, with the car on level ground, and the dipstick still shows 3/8" above the Full mark. Checking the Red Line bottle shows about 16 or 17 ounces left.

So the dipstick is telling me that the gearbox is overfilled, yet the volume of oil left in the fourth bottle is telling me that the gearbox is underfilled. If the gearbox capacity actually is 3.7 quarts, and 3.7 quarts should reflect on the dipstick right at the Full mark, then the last bottle of oil should contain a bit less than 10 fluid ounces.

It just doesn't add up unless some of the old oil remained, but I can't see how, or why. Anyone have an idea what's going on here???

[lostinthe202]

Do you still have the oil you took out? if so you could measure how much is there. That's about all I have to offer.

 

good luck!

 

Will-

[Gloyale]

Now, the manual says that the gear box capacity is 3.7 quarts(US). At the fourth quart bottle, I used half of it, then checked the fluid level. Well, the dipstick showed the fluid level about 3/8" above the Full mark.

I"ve since checked the level several times after driving, with the car on level ground, and the dipstick still shows 3/8" above the Full mark. Checking the Red Line bottle shows about 16 or 17 ounces left.

 

It' impossible to get the very last bit of old gear oil out. Probably about 10-20 ounces of it will tay inide the trans. Go by the dipstick and don't worry too much. Hell if you want, throw the rest in. It won't hurt anything.

 

I alway run my manuals a half quart overfull. Otherwise they are too noisy.

[Setright]

Drive, let it cool overnight on a level surface. If the level isn't more above Full than you describe, don't worry about it.

[Bluestone]

Ok, guys, I'll rest easy. Thanks for the "relax, don't worry about it" replies.

I've heard some, OH GOD...DON'T OVERFILL THE GEARBOX WHATEVER YA DO! warnings before and it sorta put the fear of God into me, know what I mean?

Just want to treat my Subie right so she doesn't bite me in the rump roast.

[2X2KOB]

The rule about not overfilling transmissions probably applies more to automatics - they can foam up the fluid if overfilled, which leads to all sorts of hydraulic related problems.

[Gloyale]

I should clarify.

 

I only recommend overfilling by 1/2 quart or so, in manual transmissions. The level inside the case is important, and if it is too high, the front stub and rear driveshaft outputs can leak or blow out the seal. They are not supposed to be submerged by the oil level.

 

But a Manual transmission case is so long, that 1/2 quart amounts to barely any rise in the fluid level. Seems to help quite a bit with a whiny diff though so I do it regularly.

 

Greatly overfilling any of our subaru transmissions isn't good. 2K2OB is correct, automatics can foam or have other issues when overfilled. And Manuals(*or auto diffs) when greatly overfull can tend to blow out seals.

 

For just the front diff portion of an automatic it is OK to overfill 1/4 quart or so if you have a whiny diff.

[Strakes]

In my 02 Wagon, I consistently overfill the manual transmission. Nope...not on purpose. Trying to get the right amount back in has eluded me for a long time. In order to counteract the inability to perform a simple task, I went to the local Advance Auto Parts and bought the following for $9:

 

http://www.ipdusa.com/Volvo-850/Tools/Fluid-Syringe-for-Manual-Trans-and-Differentials/p-72-729-2481/

 

Now, when I overfill, I use that to suction out any excess until it's just right. This suctioning out of excess oil, of course, has resulted in spilling gear oil all over the stategically placed catalytic converter...which I get to smell for weeks as it slowly burns off.