G'day Ozark
I can tell you that there is some difference in the hi and low range of the L series. On the driver's side (oz side this is) of the gearbox there will be a little lever above the diff output shaft. Have some one change between hi and low range in the cab, if this little lever and rod aren't moving then there's something wrong with the mechanism that does this job.
Subarus don't have a true transfer case - their transfer case is built into the gearbox on the input shaft above the front diff. Its very tight in there to fit anything other than the L's low range which is the best subaru low you can get. The ratio is 1.59:1 - nothing like a "real 4wd's" low range but we're generally that light that we don't need it
And "changing" the diffs in a subaru requires a box pull down and with the L serie PT4wd gearbox you need some great welding and re-strengthening skills to change the ratios in them. The EJ AWD gearboxes are loads easier to change diff ratios - split box, swap ring gear and pinion shafts and you're done. Down side is that these boxes rely on an LSD as their centre diff so aren't truly locked like the L's gearbox - or most other 4wd's for that matter!
The L series' 4wd engaging mechanism is in the rear of the gearbox, it simply operates a type of dog clutch to lock the rear drive to the front drive. Then there's a complicated multi spring and ball setup that allows the same mechanism input shaft (the one connected to the lever in the cab) to select low range.
Here's a pic of an L series gearbox in stock form: You can see the shaft from the rear of the gearbox that goes to the lever above the front diff, this is the low range selector lever.
Here's a pic of the gear box with the top plate removed - those darker bits you can see are the 4wd engaging and low range selecting mechanism! Its pretty crazy:
Here's the bird's eye view of that cover plate space. Cab lever input from the bottom of the pic, low range selector rod out the top of the pic:
And here's what every subaru gearbox looks inside - except the 6 speed. The single range gearboxes don't have the low range gearing above the diff, just a solid piece of shaft:
So as you can see this is a pretty tight for space unit. They've jammed just about everything they can into the smallest space they could! The bottom shaft with the pinion gear on it is solid - the EJ gearboxes have a hollow tube that the lower gearset is fitted to with the pinion shaft passing through this tubing. This allows the centre diff to do its stuff - the centre diff is located in the rear of the gearbox! Like I said, the Japanese have got the most out of this box design since 1984/85ish its basically in its same form now with the 5 speeds! Minor things have change as you'd expect but its basically the same
Hope that helps you out mate! I also hope your brain isn't dribbling out your ear now - it took me some time to get my head around all of this to do what I've done with my gearbox! The next box is going to be the box of all boxes! Just need the coin for a professional builder to put this one together so its mickey mouse...
Cheers
Bennie
to ORS.
