legacycentral bbs

Alright, lets get started.

I have a 1994 Legacy SS rally car, running a 2.2L NA engine and the stock 3.9FD Turbo transmission with a rear mechanical LSD out of a 91 SS.

I bought a 1991 Legacy L that had a good 4.11 transmission in it, stripped down the car and sent it to the junkyard. However, I forgot to pull out the pedal assembly, clutch cable, etc. because I was under the impression I could swap over my hydraulic setup into the 4.11 with no issues like on newer transmissions. So when the time came to put in the 4.11 transmission and saw there was no boss for putting in the turbo clutch fork I was rather.... pissed. But probably should have done more research.

So! My question is now, can I still salvage this transmission and convert it to using the hydraulic clutch setup that I have in my rally car? The 3.9 FD is absolutely killing me on high speed straights and making my transmission a 3-speed trans rather than a good ole 4-5 speed rally transmission.

Also, I have 3 diffs. The mechanical LSD rear that is a 3.9. A 4.11 VLSD from an 01 RS, and the stock 4.11 Open diff from the parts car. Is it possible to swap the Mechanical LSD guts from the 3.9 into the 4.11 (either VLSD or the Open one) so that I can have a 4.11 Mechanical LSD? I absolutely love love LOVE the mechanical LSD over the open or VLSD (might as well be open) so ideally I would like to keep that, while running the 4.11 gearing.

Annnnnd Legacy experts engage!

You can convert the 91 4.11 transmission to be hydraulic, however it will retain the push style clutch setup. There is no way to convert the push style clutch setup to the pull style setup.

The hydraulic push style transmissions are found on the RS's and most if not all newer Subarus. What you will need to convert to the hydraulic setup is to move the pivot ball to the other boss in the transmission and use the hydraulic clutch fork. I believe you will have to tap that boss for the pivot ball. Ideally if you can grab the clutch fork, and master & slave cylinders from a donor, that'd be the easiest. You can also get any clips or other doo-dads that you need.

You should be able to use existing clutch MC, however due to differences in bore diameter, you may feel more or less effort as a result of different size pistons. So you can try keeping your MC and if you don't like the feel or travel, swap the MC to the matching one to the slave cylinder. I would recommend against gettering a "new new" clutch MC since they have built in dampers. Try to find one from the late 90's.

Regarding the rear diff, the one out of the 91 SS is not mechanical, it is also VLSD. I seem to recall reading something about someone swapping one of the VLSD units to a 4.111, but don't recall the details. Have you searched to see if anything came up?

So I went to my storage unit to check out the trans I still have (the 4.11 from the 91) and it doesn't seem to have any mounting provisions for even an RS style hydraulic push type. I also remember there was no way to mount the hydraulic clutch fork because that one requires the pivot cylinder (or whatever you want to call it). The trans I had didn't even have a hole or cover plate for that.

Now it doesn't seem like it even has any mounting holes on the front edge of the trans to mount an RS style hydraulic slave cylinder.

Am I just missing something painfully obvious? Wouldn't be the first time. Haha

I put the Turbo LSD in my 4:11 N/A diff, straight swap to 4:11 diff. I just measured everything before and after.

Matt, first off, congrats on the finish at 100aw!

Secondly, the only way to make those 4.11 gears usable without fucking with a new pedal box and all that junk is swapping cases.

It's how I'm running 4.11 gears from a legacy outback in my overboosted rusty sleeper DD. It's easier than it might appear too.

Open your 3.9 hydro(or a blown donor, saving your good 3.9 for a rainy day) case, rip everything out, both gear shafts, forks, rods, front diff, reverse, et cetera and drop in the guts from the 4.11 cable case. I've done this twice now. First time was to use another 3.9 gearset from some cable clutched 2.2 impreza, and then again 2 years ago to install the 4.11's from the outback I mentioned above. The lower ratio is better for their longevity too. (I've destroyed THREE 3.9 2nd gears, so I speak from experience) Once you get these 4.11 out of the cable case and into a hydro case they should last a while since you aren't pushing 300+ ft lbs.

Let me know if you need the FSM's...

Huh, interesting idea.

I do have a WRX trans of mine that was blown with type RA 1-3 gears (blew 2nd gear) that is just sitting in my garage. Wouldn't mind holding onto the 3.9 just in case, or be able to sell it later on.

Really is that simple? No machining needed, shimming, etc.?

Yeah, it's simple. I would check the lash on the front diff though. That's easy though.

The gear shafts don't get disassembled, just lift them from the case half and drop it into the hydro case half. Same with the diff.

What year is that wrx trans?