Best gear oil for Subaru front and rear differentials? Automatic

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slacktide_bitog

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98 Subaru Forester, automatic transmission, EJ25D
looking for the best gear oil to use in the front and rear differentials

What kind of gear oil is best to use? It calls for 75w90 for the front diff, 80w90 for the rear diff. GL-5 for both
I know I can probably use 75w90 for both

Is Walmart Supertech Synthetic 75w90 good? I know it's only $7, so it's a good price
smile.gif

I'm also considering Castrol Syntrax and Liqui-Moly #2048 GL5 75w90
 
I've used the Supertech in my Subaru transmission/differential several times. No problems, no noises, no issues.

However, I have a manual transmission, for what it's worth.
 
You, by changing the differential fluid, will have done something that probably 1/2 of Subaru owners have NEVER done ... and 99% of the people who never changed it never had a problem with the diff's.

The non-turbo Subaru differential is a low torque, low load application. It is not under a ton of stress, towing heavy loads or dealing with huge horsepower and torque. Pick an oil that meets the requirements, change it out, and drive some more !
 
We use Amsoil Severe Gear (SVG) 75w90 in all Subaru's at my shop, front and rear. Never had an issue.
 
Originally Posted by SubieRubyRoo
I use Motul Gear 300 in all my Subarus and all the Subarus I service... its specs are SUPER stout. Amsoil Severe Gear is also a great lube.



Motul 300 as well in my suby, which reminds me, I have to change fluids in the spring.
 
Amsoil Severe Gear 75w-90 in both differentials on my FXT. Probably overkill, but I like overkill.
 
Originally Posted by slacktide_bitog
98 Subaru Forester, automatic transmission, EJ25D
looking for the best gear oil to use in the front and rear differentials

What kind of gear oil is best to use? It calls for 75w90 for the front diff, 80w90 for the rear diff. GL-5 for both
I know I can probably use 75w90 for both

Is Walmart Supertech Synthetic 75w90 good? I know it's only $7, so it's a good price
smile.gif

I'm also considering Castrol Syntrax and Liqui-Moly #2048 GL5 75w90



I cant believe you missed the tens of threads on this subject!
smile.gif


I had to drain out the dealer installed mobil lube and put in supertech due to rear whine.

rear whine GONE.

Mobil gear oil has never worked for me.
The dealers around here use it ( Mobilube HD 80W90 and I always have issues after the r&r.
In the Nissan it was noticable drag and poor cold weather performance.

Supertech, Castrol Pennzoil and Valvoline. Whatever is 6 bucks a qt. Not expensive stuff to make.

so no need to spend 15 or 20 bucks a quart

Have at it.

and dont install in thr wrong hole up front.

Subaru has too many drain, fill and check ports - at least on the newer cars with CVT.
 
Originally Posted by fozzdesy2001

You can't go wrong with Mobil 1. My Subarus never have a problem when the differentials are filled with i

Amsoil 75-90 in my front and read diff's at 30k. First time for me as I've used Mobil 1 for every other diff change in all my vehicles.
 
Originally Posted by ARCOgraphite
Originally Posted by slacktide_bitog
98 Subaru Forester, automatic transmission, EJ25D
looking for the best gear oil to use in the front and rear differentials

What kind of gear oil is best to use? It calls for 75w90 for the front diff, 80w90 for the rear diff. GL-5 for both
I know I can probably use 75w90 for both

Is Walmart Supertech Synthetic 75w90 good? I know it's only $7, so it's a good price
smile.gif

I'm also considering Castrol Syntrax and Liqui-Moly #2048 GL5 75w90



I cant believe you missed the tens of threads on this subject!
smile.gif


I had to drain out the dealer installed mobil lube and put in supertech due to rear whine.

rear whine GONE.

Mobil gear oil has never worked for me.
The dealers around here use it ( Mobilube HD 80W90 and I always have issues after the r&r.
In the Nissan it was noticable drag and poor cold weather performance.

Supertech, Castrol Pennzoil and Valvoline. Whatever is 6 bucks a qt. Not expensive stuff to make.

so no need to spend 15 or 20 bucks a quart

Have at it.

and dont install in thr wrong hole up front.

Subaru has too many drain, fill and check ports - at least on the newer cars with CVT.




You are right! My 17 has the CVT and there are plenty of ports. Lot's of people have in error pulled the CVT drain.
 
Subaru manual transmissions of that era (but probably not only that era) are picky about what lube you put in, but the diffs on an automatic should not be as long as it's the correct spec.
 
What else only does not work for you but works for thousands like me in the private and industrial sectors?
 
I buy Delvac 1 from Summit Racing for my GM lockers (Eaton) … think it's there mainly for Porsche track guys … but carries OTR certs for long runs …
 
In your situation, I would use Amsoil Severe Gear 75W-90 in the front and their Severe Gear 80W-90 in the rear.

And you can rest knowing you definitely are protected. OVERKILL but I like it...
 
Originally Posted by ARCOgraphite

I cant believe you missed the tens of threads on this subject!
smile.gif


I had to drain out the dealer installed mobil lube and put in supertech due to rear whine.

rear whine GONE.
-snip-
and dont install in the wrong hole up front.

Subaru has too many drain, fill and check ports - at least on the newer cars with CVT.



Yeah, I didn't really pay attention to those threads in the past because I didn't think I'd ever get a Subaru
blush.gif


Most of the threads I've come across were for the manual transmissions, which seem to be more picky, as the trans is combined with the front diff in the manuals, but not the automatic I'm dealing with
45.gif
 
Originally Posted by slacktide_bitog


Yeah, I didn't really pay attention to those threads in the past because I didn't think I'd ever get a Subaru
blush.gif

....
45.gif



I hear Ellen will come to your house personally and Welcome you to the Club
smile.gif
 
I've used both Mobil and Valvoline 75W-90 in our Subarus. No issues. The OEM fluid can be very viscous, in our Forester, it came out like molasses.
 
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