How do I tell what gearing my tranny/diff are?

[JonOfScio]

AWD, open diffs. 1995 Legacy L, converted to AWD and rebuilt using parts from all sorts of subies.

 

Now, my question - just out of curiosity, how do I tell what my gearing is? 3.90? 4.11? One way to simplify it I suppose, is to know whether or not my driveline in my car is the same size and length and swappable with any other model of subie driveline. (IE: 2door impreza, 4 door impreza, years of cars... ect.)

 

So if my driveline is swappable with the legacies only, then that would limit it to either a 4 door sedan just like the car is, or a wagon (or outback wagon)

 

Now, I think my speedo is off... I've passed radars many a time and it's ALWAYS way lower than what my speedometer says I'm doing. IE: I've passed a cop doing 70 in a 55... and then passed a radar - I was the only one on the road, and it said 60mph. It's always just about this same amount off. Passed one once at 20 and it said 16. Once at 30 and it said 25. So it's always off it seems... is this normal of radars? the color of my car? my sunglasses? (j/k on the last two)

 

So anyhow, when we lifted my car (at work) and the mechanic (to save time from me doing a clutch job I took it to work and had them do it) dropped everything, I could see that EVERYTHING under the car comes from B&R, which is a parts/wrecking yard in corvallis, OR. It was yellow dots and stock numbers all over the place... But, unfortunately, no tags on anything. so I can't identify if my tranny does come from an outback (which would explain for the speedo being off. they use 205/70/r15s. which I will have a complete set of alloy 6 spoke outback wheels with good tread next week! HA!) or if my diff is 3.90 or 4.11. It's really unimportant to me, but I know that if it's 4.11, I could get an LSD right? do they make 3.90 LSDs that bolt up from other subies? (in case mine is 3.90)

 

thanks for any who reply

[Hondasucks]

Your car is probably a 4.11 but I could be wrong, my 91 was 4.11. The transmission itself wouldn't be different, but there are probably several different speedometer drive gears, and if your car has the wrong one it will throw your speedo off. Best bet is to go to the subie dealer and order a drive gear for your car (EG 95 Legacy L AWD) I don't know about drive shaft differences etc.. I think the wagon and sedan are the same, but the Impreza might be shorter not sure.

 

Easiesty way to tell ratio is to clean the crap off of the rear pumpkin and read teh sticker. Or mark the drive shaft and see how many revolutions it takes to make one revolution of the tires. If it takes slightly less than 4, then you hve 3.90 but most likely you hve 4.11.. I think the only ones wiht 3.90s were the Turbo models (Automatics might have had 3.90 as well, not sure) and the LSDs are HARD to find for those.