Changing transmission & rear diff oil

[vincentmoy]

Hi all,

 

I think my 98 OBS 5MT is ready for a gear oil change in trans & rear diff.

 

It has 183k on it and not sure if it has ever changed gear oil before.

 

I'm wondering if it will hurt the trans/ diff if I change the oil cause I heard that some hi miles trans. went to heaven after the oil change.

 

Anyone heard of anything like that?

 

Thanks

 

Vincent

[Rooster2]

I don't know if the oil in a 5 speed trany ever needs to be changed, but it sure wouldn't hurt anything.

 

As far as changing lube in the rear dif, I tried doing that on my 99 last weekend to no avail. I bet you will find bolt/plugs to be super tight, like I found on my car. Suggest you use a half inch drive breaker bar, then slide a long pipe over then end of the breaker bar handle to gain added leverage.

 

Be sure to loosen the top bolt/plug first, where lube is added. Otherwise, you will be screwed if you drain the lube, but then can't get the top bolt/plug out to add new lube.

[vincentmoy]

I don't know if the oil in a 5 speed trany ever needs to be changed, but it sure wouldn't hurt anything.

 

As far as changing lube in the rear dif, I tried doing that on my 99 last weekend to no avail. I bet you will find bolt/plugs to be super tight, like I found on my car. Suggest you use a half inch drive breaker bar, then slide a long pipe over then end of the breaker bar handle to gain added leverage.

 

Be sure to loosen the top bolt/plug first, where lube is added. Otherwise, you will be screwed if you drain the lube, but then can't get the top bolt/plug out to add new lube.

 

So what kind of method you use to try to loosen your bolt?

[Olnick]

So what kind of method you use to try to loosen your bolt?

 

Vincent--check post #5 in this thread. It worked for me.

 

http://www.ultimatesubaru.org/forum/showthread.php?t=97108

 

Good luck.

[Rooster2]

So what kind of method you use to try to loosen your bolt?

 

My effort was last weekend without success. The advise I got here was to use a half inch drive (really breaker bar) with a long bar slipped over the existing handle for added leverage. I will try this on this coming weekend.

 

Another guy suggested using the breaker bar, and with the help of a car jack, he literally pushed the breaker bar handle up to untighten the bolt. Guess that would work too.

[vincentmoy]

My effort was last weekend without success. The advise I got here was to use a half inch drive (really breaker bar) with a long bar slipped over the existing handle for added leverage. I will try this on this coming weekend.

 

If you use this method with success, would you mind PM me? I'm still in the drawing board stage of acquiring what parts I need so it won't be anytime soon.

 

Thanks for help.

 

Olnick: Thanks for the PM! Appreciate it

 

Vincent

[ferret]

I just did this on MY04 for the 2nd time. First for the tranny, cover the Y pipe below with tin foil. It keeps the draining fluid from dripping , covering the pipe and smelling for weeks.

 

Also I refilled with Redline Superlite Shockproof. At their website it does not recommend it for transmissions, but a call to them will tell you they DO recommend it for a Subaru and it's syncronizers. Believe me, summer, winter, I have not found a better fluid ... smooth easy shifts even when starting in 0 degree weather. I remember with dino oil, release the clutch on a frigid day and the engine would stall. No so with this magic elixor. And I have had Subaru 5 speeds in 7 vehicles since 1978.

 

Now to the rear diff, I last did it also at 60K, now at 122K, you swore I never had those square plugs out. I even used teflon pipe tape on them and only torqued them to 30 ft lbs. Like always I couldn't budge them. But 2 years ago, I bought on sale in a Harbor Freight store the following electric impact wrench. I paid $29.99 for it on sale at the time and have since gotten my money out of it many times. I use it regulary to remove things. Never knew how I did without it and all those blood knuckles. In any case, the nose is narrow ( you can't see it in the picture ) so I put a 3" 1/2"drive extension on it and a few spurts, they were loose.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=31877

I use Mobil 1 75w-90 synthetic gear lube in the rear.

 

I only use that impact wrench to remove .... I always use a torque wrench to install.

 

P.S. word of advice ....... be certain to Get the TOP out first !!!!! If you only get the bottom out, you will have a heck of a time refilling it.

[vincentmoy]

I just did this on MY04 for the 2nd time. First for the tranny, cover the Y pipe below with tin foil. It keeps the draining fluid from dripping , covering the pipe and smelling for weeks.

 

Also I refilled with Redline Superlite Shockproof. At their website it does not recommend it for transmissions, but a call to them will tell you they DO recommend it for a Subaru and it's syncronizers. Believe me, summer, winter, I have not found a better fluid ... smooth easy shifts even when starting in 0 degree weather. I remember with dino oil, release the clutch on a frigid day and the engine would stall. No so with this magic elixor. And I have had Subaru 5 speeds in 7 vehicles since 1978.

 

Now to the rear diff, I last did it also at 60K, now at 122K, you swore I never had those square plugs out. I even used teflon pipe tape on them and only torqued them to 30 ft lbs. Like always I couldn't budge them. But 2 years ago, I bought on sale in a Harbor Freight store the following electric impact wrench. I paid $29.99 for it on sale at the time and have since gotten my money out of it many times. I use it regulary to remove things. Never knew how I did without it and all those blood knuckles. In any case, the nose is narrow ( you can't see it in the picture ) so I put a 3" 1/2"drive extension on it and a few spurts, they were loose.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=31877

I use Mobil 1 75w-90 synthetic gear lube in the rear.

 

I only use that impact wrench to remove .... I always use a torque wrench to install.

 

P.S. word of advice ....... be certain to Get the TOP out first !!!!! If you only get the bottom out, you will have a heck of a time refilling it.

 

That's really helpful!! Thanks man!

 

Vincent

[screwbaru2]

"So what kind of method you use to try to loosen your bolt?"

 

I know this sounds contrary but it works. I especially use this method on brake bleeder screws, I haven't broken any in years. After a good bath with your penetrating oil of choice, try turning the fastner in the tightening direction. It only needs to move a little, a 1/8 turn works. Once the fastner has moved it'll break free in the opposite direction. My father show me this about years ago and I've used it ever since.

[etc]

So what's the best synthetic tranny fluid to use?

 

1998 Subaru Legacy L wagon, AT.

[edrach]

So what's the best synthetic tranny fluid to use?

 

1998 Subaru Legacy L wagon, AT.

I'm partial to Redline 75W-90NS.

[etc]

Who has the best price on it?

 

And how many qts do I need?

[Olnick]

Who has the best price on it?

 

And how many qts do I need?

 

I agree with edrach . . . good stuff.

 

Check performance shops in your area for price. Check specs for your car for quantity needed--probably 4 quarts. Here in Honolulu it cost $10 per quart.

[etc]

Re: Redline 75W-90NS

 

I will try NAPA. Maybe they have it.

[stevetone]

So what's the best synthetic tranny fluid to use?

 

1998 Subaru Legacy L wagon, AT.

 

I'm partial to Redline 75W-90NS.

 

Uh...he has an automatic...do not use gear oil in an automatic transmission...the OP has a manual

 

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