If you plan to do all of your own servicing, as an alternative, you could drain the differential and refill with your favorite brand. Then, you would know what's in there. However, there exists a possibility that the lubricants would get mixed, anyway. Say, it's a cold winter day and you took the vehicle in to the dealer for some service work. Without asking, they'd probably check the lubricant levels of the differentials and add some if low. Sooo, your best bet is to find out what Subaru uses and keep a can or two in your garage. At first brush, it would seem that so long as the lubricant met the specification required by Subaru, there would be no problem. Possibly, there could be trouble if the lubricant base types were different such as synthetic mixed with petroleum. One place were additives can cause problems is the seals. Seal materials have been selected to survive in the particular fluid chosen by the manufacturer and the maker may not have run long term life tests on a variety of seal and lubricant mixes, but only tested the combinations they planned to use. To protect themselves from claims and customer discontent, they warn the user to use only the recommended lubricant. Mixing in an alternate lubricant may, or may not be ok. Let us know. Did the dealership tell you what to use? They may not know if they are supplied by Subaru.

I did not find a 5 hp engine. The link below is for a 5.7 hp engine. Is this one similar to yours? By the way, what is the year of manufacture of your engine? Here is a link that might be useful: Subaru Horizontal Shaft Engine

1929 Model A Ford, 4 dr with window shade, roll-up, style curtains on rear side windows. Color black - was there any other color? 1949 Plymouth, 6cy, 2dr, 3-sp manaul, column shifter, Blue, the last of the fast back designs. (Horrible rear visibility) 1954 Dodge, 4dr, w/ Red Ram V-8, 3-sp stick. This one was not a large displacement engine, rated only at 140 hp, but was the smoothest running engine that I have ever owned. Color: White top over Blue bottom. 1960 Plymouth Valiant, slant six, 100 hp, automatic, 4 dr, blue. Low torque engine - couldn't get out of the way of itself. Good fuel mileage. No power steering - didn't need it - very good handling. The next year, a longer stroke engine was offered with much more torque. This one was very driveable and became the engine of choice. 1964 Dodge Dart, 273 cid V8, 4 dr, automatic, white w/red interior. This one was a good compromise between, power and fuel economy and room. I wish that I had another similar car today. This one was well liked. The engine was a thin wall cast version of the 318, but with a smaller bore. The bore centers were the same as the 318, thus it was manufactured on the same engine line as the 318. Many engine parts were interchangeable with the 318. 1969 Dodge Coronet, 4 dr, 318 cid V8, blue Just an ordinary sedan to hold my growing family. EPA fix-ups began to appear and degraded performance a bit without any fuel mileage increase - lower compression and a low ratio rear end ( 2.71 to 1) Though I put 115,000 miles on it before moving on. 1974 Dodge Sedan, 400 cid V-8. EPA had struck this engine hard. It was based on the admired 383 V8, an engine upgrade option for station wagons and police cars. To meet EPA requirements, Chrysler lowered the compression ratio and installed a very mild cam. The resulting power was so embarrasing that chrysler bumped the displacement up to 400 cu in to gain back a bit of performance. (An earlier 383 in good tune would run cicles around it.) 1974 Oldsmobile Cutlass, 4 dr, V8. Bought used for a 2nd car and commuter. Had to put in a valve job after 1 yr ownership. As it neared the end of its life, sold it to a junk yard. I didn't want to see this on the road again as it had become dangerous. The body metal holding the rear body mounts had corroded away. The best part of this car: The radio. 1975 Buick Apollo, 270 cid V-8 (Oldsmoblie engine), 4 dr, Yellow. The smallest V8 made by GM. Not a good car. Was purchased as 2nd car for a winter-beater and comuter. Let my kids learn to drive with this one - they were not going to win any stop light drags with it. In fact, they were lucky go to get across a big intersection before the light changed to red. I bought this car during a period of runaway inflation. It was 3 yrs old and loosing value at a lesser rate than my hard earned cash in the savings account. That became part of my rationale for picking it up for a 2nd car. 1976 Buick Estate Wagon, 4 dr, 455 cid V8, Clam shell rear gate and window; 19 ft long! This one was the family land barge and vacation machine. The family had now grown to 5 and this station wagon held us all in comfort on long trips. This was the first year that GM put catalytic converter on all of the Buick line. (GM had put catalytic converters on a few select models the year before as a field trial.) With the converter, Buick put in a better cam and iginition advance curve and got better power plus 2 more miles per gallon. I garaged this one every winter taking it off the streets just before road salting began and it stayed off until next spring after a rain had washed away the salt. I kept this one 13 yrs and it was in very good condition the day I traded it in. It was showing signs of a catalytic converter plugging up, otherwise, the engine was in fine shape. 1980 Chevrolet Citation, V6, 4dr + hatch back, green, my first front wheel driver. A fair car. Had a very good useable interior layout and driver visibility - wished there was a car with those features today. Had too much braking on rear wheels compared to the front - gave the car a tendency to swap ends while braking on slippery surfaces. Over- sped the engine one time when the tranny failed to catch 2nd gear on a downshift - it went all the way to 1st gear at 45 mph. Loosened a rod bearing. GM got the steering geometry right on this one - no torque steer. The Chrysler K-car was plagued with torque ateer. 1983 Chevrolet Citation, V8, 4dr, white Engine was de-tuned a bit, but otherwise the same as the 1980. 1981 Pontiac Phoenix (twin of the Citation), 4 cy "Iron Duke", 4 dr., Brown. A dog. Served as a commuter. When climbibng a grade, engine vibration could be strongly felt in the steering wheel - each firing of the cyliners were perceptable. No. 2 son, a new driver, burned the engine up while driving home from a days outing with the guys. He had not been watching the oil level - it ran out. 1989 Dodge Dynasty, 4 dr, V6, Light blue 1st yr for Chrysler's new computer controlled transmission. It had issues - shifting algorithm should have been revised. It was programmed to give good results on the EPA fuel mileage test, but otherwise, was bad for commuting traffic. Car was too softly spring - people riding in back tended to get car sick. 1992 Dodge Dynasty, V6, 4dr, White. A much better car. Better handling. Held front alignment very well. Shifting algorithn improved, but still had glitches. I put 90,000 miles on it and sold it (cheaply) to my daughter. She moved out of state and later sold the car to her friend. By then, the rocker panels were holed out. I saw the car two years ago and it was still running with upwards of 140,000 miles on it. 1992 Jeep Cherokee, inline 4.0 L 6CY, 4dr, with part and full time 4-wheel drive, Red. Really liked this one. Gas mileage wasn't great, but it took us all over the lower 48 states and into places where an ordunary car could not go. We photograhed many interesting scenics using this vehicle. This one was my prime winter time driver - great in snow - can't beat it. 1998 Dodge Stratus, 4 cy, dual overhead cams, 4 dr, red. An OK car - not great, but OK. Its gets very good gas mileage on trips and that is what I bought it for. Runs great. I beem garaging this one very winter and there are no rust spots. 1998 Jeep Cherokee, in-line 6 cy, 4 dr, again with part and full time 4 wheel drive, Deep Amethyst Purple (appears black under many lighting conditions). Replaces the red Jeep which was getting body rust, but ran well - had 190,000 miles on it.

I have a 2019 cross trek and she's just fine. This is our 3rd subaru. I don't think you can beat them for safety or reliability. I specifically was looking for AWD and for the safety features as, I figure as I'm aging, I'm not becoming a better driver. I especially like the headlights that turn as you turn a corner and the auto hi/low beam adjuster. The back up cameras, side lane warnings and front collision signals are wonderful. I did turn off the lane drift feature though as, driving winding country roads which I do all the time, I often cross the yellow line and the warning was annoying. But it's great that you can turn these things off. I'd turn it back on on the highway especially if it was late at night and I'd worry about getting drowsy. I'm looking to give this one to DH and get a new little sweet ride for myself. And one thing I really like about the subaru is how they integrated the screen into the dash so it looks intentional. So many vehicles, they pop the screen on top so it looks like an after thought. I would love to get another subaru for myself, but I'm looking for small, and the subaru sports car is RWD which I won't go back to. So my search continues.