Subaru Forester Front and Rear Differentials

[Titan]

Just changed a new Forester automatic to Specialty Formulation's HDS-5 in Front and Rear. Both differentials spec a GL-5 75w-90, at 700 miles...I like to get the factory stuff out soon.

But, the front differential was certainly thinner. Maybe it was thinner because it was warmer...the car sat for about 30 minutes before draining, and the front fluid was MUCH warmer. Anyway, they smelled the same, although the rear's had more gray color and there was more metal gunk on the rear's drain-plug magnet.

Then, I changed my Saab 9-2X (a Subaru in better clothes) rear differential fluid to SF's HDS-5. It already has SF's MTL-R, which REALLY helped shifting. This MTL-R is what sold me on trying the HDS-5.

I guess now all I have to do is change the Forester's autotransmission fluid to something SF makes, and I'll be set. Set for what, I'm not sure, but, I'd certainly be set for something! The Forester has a spin on filter on the auto transmission...I really like how they did that. I think I'll wait 15000 miles on the auto transmission, especially with such a nice filter on it. Anyone know if these Subaru autos are relatively trouble-free, or not? I sure hope they're better than Honda's autos.

 

[jbl]

You should be fine with HDS-5, 75W90.

What kind of front differential do you have in the Subare.

In my Volvo xc70 Mola recommended MTL-R but my front diff is an bevelgear.

In the rear end im using HDS-5, 75W90.

My manual gear box is using MTL-P.

Everything works like an dream and Molas support is the very best.

Im also thinking about HDS-5 75W90 in the front diff bevelgear. The only downside would be little worse fuel econemy. But i think the protection will be better.

 

[Titan]

I wish I could tell you the difference in the front and rear differentials. They both spec the same fluid in the owner's manual. The front holds 1.3 quarts while the rear holds 0.8 quarts, but that's all I know. It did concern me a little that the front factory fill was thinner...but, I think that was just because it was warmer. I'm trusting MolaKule's advice, plus, his advice matches the owner's manual, so it must be at least OK, if not perfect!

 

[springnr]

I have a Subaru Legacy GT 5EAT Auto. Not sure if the Forester uses the same setup but here is info for the Legacy GT.

Cntr/frnt Diff: 1.5 Quarts, 75W/90 GL-5
Rear Diff: 0.8 Quarts, 75W/90 GL-5

The AT (5EAT) uses an electronically controlled hydraulic transfer clutch Variable Torque Distribution (VTD) system that works with a planetary gear center differential to control torque allocation between the front/rear wheels.

Rear LSD(viscous coupling)
Open front diff

 

[Titan]

Sounds very similar to mine. I bet the front fluid was just so much warmer, it was noticeably thinner than the rear. Thanks!

 

[bulwnkl]

Note that Subie front diffs are hypoid units just like the rears. Thus, the GL-5 spec.

 

[Titan]

thanks bulwnkl. Nice to have someone that knows around.

 

[Cookie]

Subie auto trannies are often subject to torque bind. The average owner never changes the fluid until the symptoms occur. A flush and fluid change clears up most of them. If you actually maintain your tranny I would not be surprised if you see over 200,000 miles with no trouble.

 

[Titan]

Thanks, Cookie. I know Honda Autos have problems, I just haven't heard much about Subaru Autos. How about a drain/fill every 30,000 miles on the Subaru auto? Sound sufficient to you? That's what I'm going to do on the manual one I have.