1991 Subary Legacy - I used to ski and thought the Legacy AWD would be a real boon to driving up. It acted odd > When going up hill under power (freeway or near freeway speed) the front wheels would lose traction, spin way up (verified by the tach), and SUDDENLY the AWD would kick in. Traction would be good, then just as suddenly the AWD would dis-engage and the process would repeat itself.
I thought it was poor tires, never having had AWD before. I was not sure HOW AWD should act. My previous ride was a 4WD Toyota Tercel that you engaged with a lever. Personally I thought it was great and worked quite well but was obviously different.
Quit skiing so the car seldom gets in snow anymore, but occasionally in our driveway on a slope one tire will end up on wet grass. When loaded (I scuba dive now so the load is not trivial), when trying to take off it will spin > then suddenly engage. Engagement is not smooth, more like revving up the car a middling amount and putting the automatic transmission in gear. Now I have GOOD tires and fairly new all around.
Recently I took it in for it's first CV joint replacement (160K). The shop (Subaru only) indicated the transmission had a problem with the rear not engaging correctly. Well, how about that. They also said that otherwise it was fine and probably not worth the trouble of tranny repair. I agreed since the AWD is about 95+% not necessary. If I didn't know there was a problem, there is almost nothing other than this odd and occasional behavior to indicate it.
Then talking with a dive buddy that runs a Transmission shop indicted it could be electrical with the throttle sensor providing input to gradually engage the AWD. I did some searching and find there appears to be a bunch of such sensors.
Anyone know where to start on this issue and what to check and where? I don't have anything to check computer codes nor do I have any CEL issues.
Note-While researching I found out about the FWD fuse. I JUST put it in and will be taking it on a 100 mile test trip this afternoon. A trip around the block indicated normal driving behavior and a new FWD red icon on the dash.
Appreciate any help.
Fritz