Mobil 1 Synthetic ATF for 4AT Subaru Outback 2002

I wonder if I should replace the tranny fluid in my 05 OBW with Mobil 1 synthetic? The transmission is awful first thing in the morning.

I'm not sure. Maybe you should talk to your dealership since it is a new car. I didn't have problems with my transmission at the beginning, although, knowing what I know now, I might switch to synthetic on my next new car.

The same applies to synthetic motor oil. That's my next move. :-)

Voja

Nicolaas wrote:

I've tried Mobil 1 synthetic two times now in the crankcase, and both times it resulted in oil leaks. I did it in my 98 Legacy Outback when it was new and noticed the filter kept leaking all the time, and even the drain plug.

Now on my '04 Forester with 10,000 mi. I put it in the last change and it started leaking. I just changed back to 5W-30 Castrol

The same applies to synthetic motor oil. That's my next move. :-)

Voja

Nicolaas wrote:

I wonder if I should replace the tranny fluid in my 05 OBW with Mobil 1 synthetic? The transmission is awful first thing in the morning.

I had problem with rough shifting on my Outback 2002 4AT 2.5L. I tried changing transmission oil (petroleum) before but that didn't help so I looked into synthetic oil and discovered the following after the change:

- Much quieter and less vibration when idling

- Shifting points are somewhat higher (roughly 300rpm which I like a loot) when accelerating moderately (say around 2,400~2,500 vs. 2,100~2,300 rpm before)

- Much, much smoother shifting

- Car is way more responsive when merging onto fast highway. This was my biggest surprise since 4 cyl. with AT are notoriously known as very slow when accelerating.

Total cost of changing is around $105 CDN and I did it myself vs. $250 at the shop.

Here are few pointers of what I did:

- First I drained old transmission oil. Roughly 4.8L (~5.1 quarts)

- I lifted my car from the opposite side of the oil drain plug so that more oil can be drained.

- Then I filled it with new synthetic oil. I used, as I said before, Mobil

- Drove around for about 10 ~ 15 min. and drained it again

- Removed transmission oil pan

- Cleaned oil pan and magnet inside

- Made lot of mess in my garage - Thank God I have awesome wife, no complains there. ;-)

- Put silicon based seal (something Copper (@ Wal-Mart), can't remember now exactly what its name is) ($5.90+tax = $6.27 CDN)

- Put the pan back and left it there overnight without new transmission oil in it so it can dry better.

- In the morning I put the oil back (another ~4.8L (5.1 quarts)) and voila...

- Oh yeah, had to clean the garage. Took me 3 hours since there was oil all over the floor :-( (bummer)

I know this is not all 100% synthetic as there is more old petroleum oil in the torque converter but it sure is better then before.

My biggest problem was how to remove transmission oil pan. No real technique there except make sure engine is warm as well as transmission so that seal can be removed easier since it gets tougher if it is cold (well duh - comment to myself). Use flat screwdriver, put it between oil pan and transmission, go around the pan and separate the pan. Be careful no to push it too far (1~1.5 cm (2/5 ~ 5/8 of an inch) is good enough) as you may, God forbid, break some wires inside. You'll see what I mean when you remove the pan. Make sure to thoroughly clean the pan and the transmission side from the old seal, so that it fits properly when you apply new seal. I cleaned both sides with brake cleaner spray. Don't spray it on directly but spray it on a peace of cloth and clean it with cloth. You'll have to rub it a little but that will make sure that you won't have leaking problems in the future.

Anyway, hope this can help anybody.

Let me know if you need more details.

Cheers, Voja

Hi,

Dumb question time--when you replaced the filter, did you put a few drops of oil on the rubber gasket, and then get it as tight as you could by hand? And did you replace the crush washer on the drain plug? These are two things I've seen people neglect, then think it was the oil that caused the leak.

My experience with "new" oil leaks being caused by a change of oil or an additive is that things like valve covers, and sometimes seals like main crank seal, camshaft seals, etc., are the places such leaks have occurred. Most likely only a buildup of varnish or something else WAS keeping 'em dry, and the new stuff simply cut thru it. No adverse effects the time I tried Mobil 1 in my Subie, and it had well over 200k miles when I tried it.

Sorry, no other ideas right now.

Rick

I did my first oil change a month ago on my WRX. Used mobil 5w-30 and have had no leaks. I had put my drain plug back in, oil filter on and found this little metal washer on the ground. Had no idea where it went. I did figured it was the crush washer for the drain plug eventually. So maybe you lost the washer and just didnt notice.

I've tried Mobil 1 synthetic two times now in the crankcase, and both times it resulted in oil leaks. I did it in my 98 Legacy Outback when it was new and noticed the filter kept leaking all the time, and even the drain plug.

Now on my '04 Forester with 10,000 mi. I put it in the last change and it started leaking. I just changed back to 5W-30 Castrol

The same applies to synthetic motor oil. That's my next move. :-)

Voja

Nicolaas wrote:

I wonder if I should replace the tranny fluid in my 05 OBW with Mobil 1 synthetic? The transmission is awful first thing in the morning.

I had problem with rough shifting on my Outback 2002 4AT 2.5L. I tried changing transmission oil (petroleum) before but that didn't help so I looked into synthetic oil and discovered the following after the change:

- Much quieter and less vibration when idling

- Shifting points are somewhat higher (roughly 300rpm which I like a loot) when accelerating moderately (say around 2,400~2,500 vs. 2,100~2,300 rpm before)

- Much, much smoother shifting

- Car is way more responsive when merging onto fast highway. This was my biggest surprise since 4 cyl. with AT are notoriously known as very slow when accelerating.

Total cost of changing is around $105 CDN and I did it myself vs. $250 at the shop.

Here are few pointers of what I did:

- First I drained old transmission oil. Roughly 4.8L (~5.1 quarts)

- I lifted my car from the opposite side of the oil drain plug so that more oil can be drained.

- Then I filled it with new synthetic oil. I used, as I said before, Mobil

- Drove around for about 10 ~ 15 min. and drained it again

- Removed transmission oil pan

- Cleaned oil pan and magnet inside

- Made lot of mess in my garage - Thank God I have awesome wife, no complains there. ;-)

- Put silicon based seal (something Copper (@ Wal-Mart), can't remember now exactly what its name is) ($5.90+tax = $6.27 CDN)

- Put the pan back and left it there overnight without new transmission oil in it so it can dry better.

- In the morning I put the oil back (another ~4.8L (5.1 quarts)) and voila...

- Oh yeah, had to clean the garage. Took me 3 hours since there was oil all over the floor :-( (bummer)

I know this is not all 100% synthetic as there is more old petroleum oil in the torque converter but it sure is better then before.

My biggest problem was how to remove transmission oil pan. No real technique there except make sure engine is warm as well as transmission so that seal can be removed easier since it gets tougher if it is cold (well duh - comment to myself). Use flat screwdriver, put it between oil pan and transmission, go around the pan and separate the pan. Be careful no to push it too far (1~1.5 cm (2/5 ~ 5/8 of an inch) is good enough) as you may, God forbid, break some wires inside. You'll see what I mean when you remove the pan. Make sure to thoroughly clean the pan and the transmission side from the old seal, so that it fits properly when you apply new seal. I cleaned both sides with brake cleaner spray. Don't spray it on directly but spray it on a peace of cloth and clean it with cloth. You'll have to rub it a little but that will make sure that you won't have leaking problems in the future.

Anyway, hope this can help anybody.

Let me know if you need more details.

Cheers, Voja

Agree with Edward and Rick. I've used Mobil 1 since day one and no leaks other than the infamous front oil seal. 107,000 miles on the Legacy and 10,000 on the WRX.

I always use factory oil filters and new crush gaskets.

Apparently Mobil did have a problem with its initial 5W-20 formula in the early 80's. Its primary base oil was polyalphaolefin, save a small amount of mineral oil used as a carrier for the additive package. PAO alone causes rubber seals to shrink. I've heard any number of reasons, but the one that makes sense is that it causes the plasticizers in the oil to leach out. Esters were added to the formula. Those apparently serve several functions. A blend of PAO and esters is supposed to improve the viscosity index, improve additive solubility, and keep the rubber soft (some esters are used as rubber plasticizers).

I remember after my first second oil change, I noticed that I had left the original crush washer on along with the one I used on the first oil change. It was somewhat skewed and not on correctly. The seal was tight and there were no leaks. I thought I double checked it. Now I absolutely make sure that the old washer is gone.