NOOB 90 & 93 Legacy TRANNYS? open/LSD tag ID........WHEW

[Red Knuckles]

Hi.

This is my first post here.... ...I feel fine.

I have several questions, I don't know the protocol if I should post them individually or all at once. They are all related, so I voted on all at once.

What I have:
I have a '90 Legacy 4EAT AWD and a '93 Legacy 5MT AWD. I've gone back 7 pages looking for this, and probably missed it several times...

What I want:
I'm seeking info/links to

1. How to decipher vehicle tag/label codes

2. Which tyrannies interchange (bolt in and electrical) in the '90 Legacy AWD? (works, no rear drive -towed wrong I think, and now additionally no speedo- )

3. Which type differential my cars have (open, LSD and how this is determined) Also, what is the correct rear differential gear ratio for the 90 4EAT Legacy? (It was switched, possible with the wrong gear ratio, hence perhaps why no RWD- fried viscous cup?) The 93 5MT has 4.111 rear end.

4. Long time ago I had a link to an article/forum discussion where a guy had opened up the console on a 4EAT car and jumped/crossed/disconnected some wires to make it a manual awd. Anyone know of this? Is this the duty c solenoid?

5. I seem to recall reading that the 4EAT Legacies are LSD, 90% front / 10% rear wheels power.
and
The 5MT Legacies are open diffs, 50% front / 50% rear wheels power.

Is this correct?

Thank you, Thank you, Thank you in advance.

[skid542]

I can't answer all your questions but I'll hit the ones I can.

1) No clue but I think there is a sticky in the body forum?
2) Physically any EJ tranny will mount to any EJ motor. There are a few issues about going between AWD and MT, do a search for Josh's AWD -> 5MT conversion. He did a good write up of his endevars.
3) I have a FWD so all those numbers for the centers and rear drive ratios all get mixed up for me.
4) I believe that it was Ciper that did this. There has been a lot of discussion about the duty c solenid but that's beyond me. You can however just put in the manual button and shift when you want to (or so is my understanding)
5) The 4eats I beleive you are right about the power distro though I think it may change depending on loading (??). The 5MT however is a 50/50 split.

Hope this helps and welcome to the board.

[Red Knuckles]

skid452 -

Thanks. On the tranny interchange, I just want to swap the 90 auto with another auto...if I have to...the easier the fit the better for me.

[skid542]

If you're swapping a another phase I into your 90 then you shouldn't have much trouble aside from possibly some wiring issues which can be completely alleviated if you get the new transmission with the harness (or so is my understanding, others here are much more knowledgable on transmissions than me).

[THAWA]

1 what exactly are you trying to decypher? If its the vin there's a link somewheres. If it's the tranny there hasn't been anytthing I've seen that breaks it down. I'm actually trying to figure this out myself.

2 to expand more on what skid said I believe all of the phase I tranny's (up to 96?) have the same connectors and use the same wiring pattern, with the exception of the svx.

3 Almost all subarus have an open front diff. The only ones I've heard of with a front LSD are certain versions of sti's and other special subarus. All of the new gen of subarus have some version of an LSD in the center, whether it by a viscous coupling, a clutch pack, or a planetary gearset, there's something in there. In the rear some trim levels of every model had LSD's. From Turbo legs, to GT's, to RS's, to XS's and so on. In the 90 you have a MPT clutch pack in the center and an open in the rear. In the 93 you have a viscous coupling center and an open rear. All 90-91 NA legacy's are 4.111 Final drive ratio which means 4.111 front and rear ratios aswell.

4 If you are talking about the thread where ciper said something about someone that made a "automonus manumatic" or something I dunno about it. But I dont think duty sol c has much to do with it. That just controls the lock up on the MPT clutch pack. Also the manual button doesn't do what you think it does.

5 Subarus official stance on the standard 4eat is a 90-10 ratio that transfers power when needed. However in regular driving you're rarely at that ratio. I'd say most of the time you're at like 70-30 or so. But it still varies power. But yeah the regular 5mt is 50-50 with a viscous coupling.

[Red Knuckles]

what exactly are you trying to decypher?

Ok, on another vehicle I have..... a big Ford truck, after much surfin', I discovered interpretations of numbers on differential and door tags that tell me what gear ratio & if it's LSD or open.

This saves time at the JY, and is helpful in car shopping. I'm just curious if this kind of info can be gleaned from subaru tags.

I guess concerning my differentials, I'm looking for "What is my differential?" (Thanks for your response) AND "How do you know that?" Is it just time and experience?

Manual button - I just read a post ....here I think, can't find it, about that. The gist was (I think) it tells 3rd to act like second?

In the 90 you have a MPT clutch pack in the center and an open in the rear. In the 93 you have a viscous coupling center and an open rear.

Oh. Ok, I was under the impression the 90 had VC. Is a MPT (multi-plate ?) adjustable? I've got no RWD.

Many thanks!

[THAWA]

Yeah that's kinda what I'm trying to do with all these codes. I'm beginning to understand the applied model code, but the trans code is still a mystery to me. The early differentials have the ratio and type on a sticker on the diff itself. The newer ones have a small number on the diff. I haven't taken the time to catologue any of that stuff though.

Generally speaking the codes tell pretty much everything there is to know about the car. The applied model code for instance tells the model, body style, trim, year, engine, trans, and destination on legacy. The engine code I still dont completely understand but from what I've seen tells the type of engine, size, head type, fuel type, turbo/na, and revision. Trans code I have yet to decypher

"How do you know that?" is yes from time and experience but there's about 4-5 different ratios in all the new subarus; 3.545(SVX, rear of MT WRX), 3.7(I "think" all FWDs), 3.9(Leg turbo, 92-94 NA leg auto, front of MT WRX), 4.111 (many cars, 90-94 NA MT legs, 90-91 NA AT legs, all MT RS's, Auto WRX, many foresters, most of the new MT turbos), and 4.444 (all AT RS's, more foresterts, most of the new AT turbos, etc). Most of the old subarus were 3.7 or 3.9 aswell.

The TCU adjusts how many clutches in the MPT (yes Multi-plate transfer) clutch pack to lock together to vary the rear power. You can't easily adjust it yourself. You'd have to rewire the Duty sol C to do that. Sounds like either your clutches are worn to all hell, or your duty solenoid C is crapped out, stuck at 100% duty.

[Red Knuckles]

THAWA -

Well, that's kind of discouraging; open differentials front and rear. So if I get a little side lean and lose forward momentum in snowS (spin-out), I've got a two wheel drive car. ? Or in the case of my '90, a one wheel-drive. lol.

The '90 runs like a top, speedo out @218k. I think where the speedo cable goes into the tranny there is an adapter that has a nylon gear on it. Believe I broke that (yep, stupid with a screwdriver), and I suspect the case has to at least be split, maybe the tranny removed, in order to replace it. Correct?

On the MPT being worn out - a little history: was my mothers car, she bought it used. She gave it to my sister, who drove it for a few years and gave it to me. When the mother had it....ok, long story short version....new tires installed, ma drives a bit, rear end lock up, brother-n-law & I replace w/JY part, ma drives a bit more another lock up, next rear-end in in 45 min., we LOOK, one new tire is 195 not 185. Ok, on first lock-up vehicle was towed. I suspect incorrectly. ALSO, whole time my sister drove it and for the first two years I drove it, the check engine light is on. After a lot of hugabah with the trouble codes and what-not, I figure out it's (as I recall) the purge control solenoid, $90, and this clears up all 4 (I forget what they were) trouble codes. And then I had AWD!!! And it ran a heck of a lot better!!!

Still runs great, but no RWD, AWD didn't last 6 months, and of course the engine light is on, I haven't checked the code, but it came on right after I broke the speedo and drove the car....and turned on the cruise control. Anyhow it was in (I think) a sort of "limp-in" mode for at least two years...where only the front wheels have drive power. I believe I read where this is hard on what I thought was some mystical viscous cup, but now am informed ( Thanks!) it is a MPT device.

Maybe it just needs a duty c solenoid? That's why I was asking about the console wire switching. Seems like I read where that was a way to test the solenoid. Dang I CRS!

ok
That's my story and I'm sticking to it. More or less.

Sorry, sleep deprived. Off to have subaru repair nightmares.
Hey thanks again!