This weekend I'm going to change the differential and gear oil in my 2000 OBW 5 speed. What are your recommendations for the the differentials and the gear oil? Can I use the same for both?

Depends on if you have an LSD/VLSD or not.

 

For the gear oil, use the "Scotty's Cocktail"

 

http://forums.nasioc.com/forums/showthread.php?t=920674&highlight=%22Uncle+Scotty%27s%22+cocktail

 

GD

I would recommend avoiding any cocktails, or magical blends.

 

Valvoline Synpower 75w-90 is the absolute best.

 

Motul Motylgear 75w-90 comes second.

 

Nothing fills the third place, since only the two above can cure the 2. and 3. gear KERRunches. Even on 20 year old Alcyones

 

On my list of experince:

 

Quakerstate 75W.

Castrol TAF-X / Syntorq 75W-90

 

Both of those above are good in newer/low mileage transmissions.

 

 

Redline 75W-90

Shell 75W-80

Mobilube 75W-90

Castrol Syntrax 75W-90

 

 

ATF fluid is a NO-GO!

Use Valvoline Synpower for both the differentials and gears?

I find Redline works well in my front/rear differntial. It flows well even at very cold temperatures.

 

I would recommend avoiding any cocktails, or magical blends.

 

Valvoline Synpower 75w-90 is the absolute best.

 

Motul Motylgear 75w-90 comes second.

 

Nothing fills the third place, since only the two above can cure the 2. and 3. gear KERRunches. Even on 20 year old Alcyones

 

On my list of experince:

 

Quakerstate 75W.

Castrol TAF-X / Syntorq 75W-90

 

Both of those above are good in newer/low mileage transmissions.

 

 

Redline 75W-90

Shell 75W-80

Mobilube 75W-90

Castrol Syntrax 75W-90

 

 

ATF fluid is a NO-GO!

Nothing fills the third place, since only the two above can cure the 2. and 3. gear KERRunches. Even on 20 year old Alcyones

 

Not true. The Redline shockproof is AWESOME. I run it along with the other contents of Scotty's. But I use two quarts of Redline in place of one of the quarts of castrol.

 

The reason this "cocktail" is prefered by many Subaru enthusiasts is that the front hypoid diff requires the additives in gear oil, but the tranmission syncro's like a lighter weight oil. These are difficult to combine without making your own blend. The Redline is great for the syncro's, but doesn't have the correct additives for the front diff gears. Thus the Syncromesh, and the Castrol.

 

At any rate I too tried a lot of gear oils, but the proof is in the performance. And based on the number of folks running Scotty's on Nasioc, LegacyCentral, and here the results are pretty clear.

 

I used to get a slight grind going into second - with Scotty's - I CAN'T shift it fast enough to make it grind. Cold, hot - doesn't matter.

 

GD

Valvoline Synpower....since I began using this oil in my gearbox (manual) the mound of metal shavings on the drain plug magnet has stopped forming. That's proof enough for me that the oil is protecting my differential gears.

Same goes for the rear diff.

 

The GL-3/4/5 rating is the big secret. Not many shelf oils span all three. And no, those ratings are not mutually exclusive.

 

 

I am not claiming that Scotty's cocktail is without result, but perhaps it's more hassle than necessary.

On a purely personal level, I prefer to use pure, well designed fluids and not mix them up with additives.

I hated uncle scottys when I tried it. Valvoline synpower is truly amazing.

 

Use mobil 1 for the diff....NOT the tranny as it is to slippery and you'll do more harm than good

I am about to switch to valvoline synpower in my wagon

You'll be glad you did

I'm assuming you guys are putting the Synpower in yourself? Called the valvoline instant oil change store next door and they wont put Synpower in any differential. I need to have mine changed but dont want to be laying on the snowy/salty parking lot ground.

Scotty FTW

 

I had some messed up second gear synchros. I lent my OBS to a "friend" of mine and he returned it to me messed up. I figured he was flogging it on the freeway and downshifted from 5th to 2nd b/c I have a short throw shifter.

 

Before scottys, downshifting from 4th to 3rd would cause a small crunch. couldn't downshift into the 2nd gear w/o a lot of grinding and crunching. First gear was impossible. On hard acceleration, 2nd would crunch and so would 3rd

 

After scottys, no downshift problems from 4th to 3rd. slight grinding into 2nd and once in 2nd 1st if no problem. NO noise at all on acceleration.

 

I realize that I will have to replace my tranny eventually b/c there is mechanical damage and this is just a band aid. But so far so good.

 

BW

Seriously: Refill with Synpower. You will be very surprised.

 

 

All those problems you describe were present in the 20 year old XT Turbo we bought recently. Synpower has cured it.