Manual transmission overhaul- '94 Legacy GT

[chrisshara]

I am experiencing some normal driveline play, internal to my transmission. I say "normal" because my car has over 300,000 miles on it. I also have the typical bearing whine coming from my transmission. I get the whining when the vehicle is in motion, under load. I figure if I'm going to go inside of my transmission and begin to replace a bunch of bearings, then I should try to get in touch with someone who is familiar with the transmission internals of 90 - 94 Subaru manual gearboxes.

I'm curious to know if there any specific parts that I should plan to "refresh" while I'm in this deep. Parts that commonly: fail, stretch, wear, deteriorate, leak, bind, tweak, etc... Is there any parts inside these gearboxes that were updated or improved with superceded part numbers ?

I'd like to go through my transmission and fully rejuvinate it, and tighten it up.

Thanks in advance

[Legacy777]

Besides bearings, the balk rings (syncros) are good to replace. However, I'll caution you that unless you are familar with taking apart Subaru transmissions, you may be better off finding a good used transmission. Even if you are familar, I still think it'd be cheaper to find a good used transmission. A lot of the parts for these older transmissions can not be purchased any more, or if you can find them, they're expensive.

[SUBYLUV871]

mine is starting to pop out of 4th when i let off the gas in my 94 gt. chrisshara, is that what yours is doing too? i think im goin to just put a used on in it. josh, is there a year range that we can reference or a better one to put in with our factory parts?. mine has alot o slop in most gears even with my short throw in it.
chrisshara , if i find a good saloution ill let you know.

[Legacy777]

Pretty much all the 5MT's are very close to being the same. The big difference is going to be the final drive ratio and if they have a 1.1:1 reduction gear in the rear final drive output. All the non-turbo first gen Legacies 90-94 had a 4.111 final drive ratio with a 1:1 final rear gear reduction. There are certainly other Subarus that have that combo, so you'll just have to look and see what you can find.

[SUBYLUV871]

so if we got one off another 94. like an L model id be the same. how do i check ratio

[Legacy777]

Yes, the L should have the same final drive ratio.

To check the ratio, you'd have to determine the amount of rotation the axle stub did when the input shaft did one rotation. The tricky part is that you have to take into account the gear that your in. The 5spds do not have a 1:1 gear. 4th gear however is the closest.

For example, 4th gear has a ratio of 0.972. If I did my math correctly, one rotation of the main shaft would equate to about 1/4 of a rotation of the axle stubs. How I determined that is divided the 1 rotation by .972 and got 1.0288, and then divided that by the final drive ratio of 4.111 and got .25025.

[SUBYLUV871]

WOW. thanks josh. im in seaech of a tranny now. ill do a thread when i do the swap.

[chrisshara]

SubyLuv871,

No, my transmission does not pop out of any gear. I get a little bit of bearing noise. I think it's the front diff. It's not input shaft bearing noise, like on the 99 - 03 Legacies - Outbacks. My bearing noise isn't even that horrible. I'm more apt to rip into my transmission to try to tighten up end play and gear slap.

I'm afraid of buying a used transmission, only to run into more problems. I have a 1995 BMW 325ic that had no second gear, so I bought a junk yard transmission and it came with input shaft bearing whine. The problem is I waited until the 30 day warranty expired, before I had the time to install this transmission. So now I have to tear down both transmissions and make (1) good one.

If my best option is to buy a used transmission, then I'll be installing a WRX drive train. This way, part are available.

[SUBYLUV871]

I have the wine too, right at 40mph and also alot of play. if you do the wrx swap id like to know how you did it. cause i have better accses to wrx parts than old legacys.

[SUBYLUV871]

will a 93 sadan trans work in my wagon you think.

[mike-tracy]

Sedan, wagon, doesn't matter. Just make sure your rear end matches the tranny's final drive.

[SUBYLUV871]

Ill use joshes theory of the rotations the .

[SUBYLUV871]

got a tranny from lkq autoparts. i knew a girl that works there, 180k out of a 94 wagon. 6 month warrenty too. retail ws $490 i got it for $300. ill be swaping it out at the end of the month when my buddys lift is freed up. what is the best trans oil recomended? and diff oil?

[mike-tracy]

Best trans and diff oil is "Subaru Extra-S."

[chrisshara]

Transmission Cocktail ?? as seen on http://www.Grimmspeed.com (1) bottle of Penzoil Synchrol Mesh, (1) bottle of Redline Lightweight Shockproof gear oil, (2) bottles of Castrol Hypoy-C 80w90. NOTED: I could not find the Castrol Hypoy-C for the life of me. I saw listings for it, but these places didn't have it in stock. I think the Castrol "Hypoy-C" type of gear oil may have been discontinuted ? Since I could not find the Hypoy-C reasonably (meaning, without buying an entire case), I used Castrol Syntrax 75w-90 full-synthetic gear oil.

Ingredient pricing:

Redline Lightweight shockproof: $22.00 (ebaY)

Penzoil Synchromesh: $10.99 (Advance Auto Parts)

Castrol Syntrax 75w-90 $10.99 ea. (x2) (Auto Zone)

[mike-tracy]

That's not "Uncle Scotty's Cocktail" is it? The one that causes accelerated synchro and gear wear?

[SUBYLUV871]

used some red line oil. seems to be shifting good. put 500 miles on it this weekend.

[cj91legss]

That's not "Uncle Scotty's Cocktail" is it? The one that causes accelerated synchro and gear wear?

It is Uncle Scotties Cocktail

[jamal]

That's not "Uncle Scotty's Cocktail" is it? The one that causes accelerated synchro and gear wear?

Does it, though?

Or maybe it's just a lot of people who treat the transmission poorly and damage the sycros expect it to be some magic fix. So they try the fluid and it shifts better for awhile, but the real answer is to not drive like a moron.

I've just been using whatever is in a gallon jug and is cheap at the parts store. When I drained the transmission after 3 years there were no chunks on the drain plug and the fluid didn't look that terrible. And the transmission still shifts pretty well for having 200k miles.

[mike-tracy]

DS1 says USC does cause accelerated wear, based on hundreds of transmissions they've worked on that were filled with it. I imagine you're right that people (continue to) abuse trannies with USC in it, but even Uncle Scotty recently started recommending that the change interval of his coctail be half of the OEM fill. Does not "fill" me with confidence.

[Legacy777]

I ran USC for a little while and wouldn't recommend it.

[James614]

I remember seeing Josh's pics of the separated fluids of the cocktail in his trans case. It may quiet shifting, but I'd just run the recommended GL-5 oil personally. I hate "liquid fixes" for mechanical problems, they almost universally hide the problem and not infrequently make it worse with fewer symptoms before total failure.

[chrisshara]

RIGHT ON JAMAL ! ! ! There is lots of speculation after I mentioned this cocktail. I have read that the 5MT is bulletproof and I've read that the 5MT is weak, especially 2nd. gear. Different people speculate different things. This was just my input from what I saw on Grimm Speed's site. I was just offering other options, opinions, insight. Naturally, it's up to each and every one of us to do our own research and make our own final decisions.

I hate liquid fixes for mechanical problems too. But if you read earlier on, Josh states that the parts to fix these transmissions are either discontinued or quite expensive to come by. So if I pour a liquid fix into my transmission with over 300,000 miles on it (keeping in mind, this transmission owes me nothing) and it corrects the issues I'm having. Then, my personal decision is to go with it, because A) it's better than almost not being able to shift when it's colder than 25 degrees and B) I have raised my right hand and solmnly sworn to increase my transmission service intervals.

If my transmission fails, then I buy another transmission. Because at 300,000 miles, I'm expecting it to fail. Because I once read "5MT's are weak, easpecailly 2nd gear." If it doesn't fail, I'll speculate that it's because I read "5MT's are bullet proof." Either way, I'm not going to be upset if my 300,000 transmission fails and I have to come up with $300.00 to replace it. In my opinion it's worth running the risk of total failure, to be able to shift. Because when I nearly can't shift, it seems like I'm about to break a synchro or bend a shift fork.

[James614]

Well put sir.