Built manual transmission or where to get sychros
 

Well since I'm not the only one having issues with terrible synchros do we have any info on rebuilding this transmission? or just replacing the synchros?

There's a 5 year/60K miles warranty on the drivetrain. Are you out of warranty?

No but I have a competition stage 3 clutch, short shifter, aftermarket bushing, and the mtec spring.

IMO switch to stock then go to the dealer.

Wouldn't they give me an issue with having a supercharger? The stock clutch slips so I had to upgrade the clutch.

Nope, perfectly ok /sarcasm.

I don't know of any shops that are rebuilding these AISIN gearboxes. The dealer told me that they don't fix them; they pull and replace the complete unit.

It's a pity, really. I like the short throws of the gearbox but that second gear synchronizer "scrunch" greatly lowers my opinion of this gearbox, and the car, for that matter.

And even if we can live with this problem, what will prospective buyers think when trying to sell the car when the time comes? I can just imagine the excuses when the buyer goes for a test drive and experiences the scrunch: it's normal; they all do that; your not holding your tongue just right; or... .

The reason Subaru dealers aren't rebuilding these things under warranty is Toyota/Aisin has a unit replacement policy, and the dealerships "don't have the special tools required for disassembly or reassembly." I put that in quotes because there are plenty of generic tools that can be used, and the service manual has the complete procedures for overhauling these units. The dealership can order internal parts.

So, if you have a trusted mechanic, it can be done.

Yes you can rebuild them I know I have one apart on my bench. You wouldn't want to though because the cost of the parts which have to be dealer ordered are outrageous. For 4th gear, synchro springs and pins, the shift collar and a bearing was over $600!!!

The Frozen North

That's for ONE gear????????????????

Yup

The Frozen North

Jesus. A whole new unit lists for about $2300.

U can find it for less that 2000$ if u search. It's a junk trans that's why its cheap

The Frozen North

True, the trans in this car seems pretty low end, especially if you do any type of FI to the car. I have a friend pushing over 400whp and is on his 4th transmission. Though he does have a pretty hefty clutch and clutch pressure plate for track racing.

I'm doing a little over 400whp myself (FBM FI kit) and shifting at high RPMs seems pretty difficult since the gears don't want to shift quikcly under full load (possibly from all the torque and inertia due to Forced Induction FI). I hoping my transmission doesn't take a crap on me too lol.

-Running a Clutchmasters FX350

someone should start working on a z33 trans swap kit or something. the trans they chose for the BRZ is very light duty, swapping in a stronger box is the only real fix. and not a v160, that's crazy overkill for a little boxer 4cyl.

The V6 Camaro, and Tacoma guys are having the same issues. The problem is the synchros, and a lot of the vehicles I mentioned above are swapping for the 2012 and up AISIN in the V6 Camaro as the first three gears have carbon synchros vs brass synchros that come equiped with them. If you get a chance test drive a 2011 v6 camaro, and a 2012 v6 camaro to see the difference. I believe you might be able to fit the carbon synchros onto the FRS.

Your friend needs a lesson on driving then man... an FX350 and pushing 400 whp (guess around 300 wtq) is nothing to break much trannies, let alone 3!

I guess we can say the tranny is not up to par for tracking, but for general street use is generally fine.

Do you make this statement in regards to OEM power or after FI is added?

After FI installed for anything close to 300 WTQ and talking from personal experience. I am at around 383 WTQ right now, with a map with 471 WTQ (on THAT map I fear for it...), and no issues to date but my statement also considers his friend tracks the car at those power levels.

Won't fit unless you want to hack the crap out of your tunnel by your thigh. I have a trans sitting here in a box and I attempted to fit it but it's just too wide, that and the starter on the twins makes it even more difficult.

The Frozen North

Sounds like time for someone like Crawford to research what it would take to upgrade this box. HINT! HINT!

If internal parts ore so expensive, then it sounds like one could offer better parts for the same cost as stock... Carbon synchros & titanium gears?
Maybe better lubrication flow and ports for a cooler?

That's a good point. There's not a lot of transmissions that are slender AND sturdy.

Built T5 maybe? Anything with a removable bellhousing (so not z33 trans) would be good, then you can make an adapter to put the FA-to-aisin bell on the new trans.

Shifting at high rpm with 400whp is no different than shifting at high rpm stock, the boxes are identical, save for the different clutch. Once the engine is WOT in gear it's a different story, but shifting should be identical.

Your high rpm resistance may be due to either clutch drag or a heavier clutch disk; I don't know how much your disk weighs compared to stock, but if it's heavier it will have more inertia and cause the synchros to work slower, this is certainly plausible. Having FI however, has nothing to do with how the transmission shifts between gears. Once the pedal is depressed the engine is physically disconnected from the tranny.

What fluids are you using?

hobbing gears to the tolerances required in modern automotive transmissions is no simple task. designing them is even more difficult. and if you switch to some sort of unobtanium that's more durable than the hardened alloy steel they're making gears out of already, and come up with a tooth profile which is somehow stronger than the one they're using on the same size gears, and actually manage to make the damn things, you're still only going to see an incremental improvement in torque capacity. if there was a way to double the torque capacity of a transmission, believe me, these guys would be doing it already. the little AZ6 is simply too petite.

I agree someone should make better quality synchros since even stock cars are having issues with them failing. Hopefully someone comes out with a breakthrough. It's a shame we can have built automatics but no one pays attention to the manuals.

PPG was making gear sets for Subie transmissions for years, for both the 5sp and 6sp boxes. I believe they had a full array of straight cut, helical, and dog box sets, etc and they were apparently a huge improvement over stock.

Another company, can't remember the name, Was doing rebuilds on Evo transmissions, reshimming and tweaking tolerances, replacing some minor parts, and it was apparently making a big difference in longevity and strength.

Haha, training is always good. Though I am not sure what he is running for his clutch. I know he was originally using the Twin Disc from Exedy.


Thanks for the break down. I know my pressure plate is heavier than stock. So it must be the synchros working slower than my foot. :p If I don't try to push it high RPMs and shift quickly I don't have any problems shifting. I am also using AMSOIL Severe Gear® 75W-90. In the rear diff I am using Mobil 1 Synthetic Gear Lube LS 75W-90. Thanks again!

Im keeping my fingers and toes crossed that someone slides an r154 in the tunnel. Not as expensive as the v160 and not as weak as the w58. Yes you lose a gear (gas mileage may suffer) but at least it should withstand higher torque/hp numbers for longer than the stock 6 spd trannys.

The r154 is not an option either due to its top mount shifter design. It would necessitate cutting the top of the trans tunnel 12" from the stock shifter forward to clear and it's too tall to say drop it down without the engine being on a less than desirable angle.

The Frozen North

Dont tell me that:(

I know that when I was working on my sc400 r154 swap the shifter would have to be extended/adjusted to sit in the center of the shifter collar, I figured on our cars this may have been the case as well, but 12 inches, damn.

I guess It may be a good time to start a v160 fund now. Woot woot money pit.

Yeah the issue is our transmissions are rod shift. Meaning they have a rod that goes into the back of the trans and the shifter is mounted on a tower like the v160. It also makes our bell housing to shifter distance very long not good for trying to find compatible trannies

The Frozen North

Take from my experience the r154 is a shitty shifting trans, I have it in my mk3 supra with 2jz swap (700-800whp) v160 is awesome but the price is crazy..I'm def waiting to see if anyone will release a build for our transmission betting that won't be cheap either. I'm sure someone will find a way to swap a different trans in for cheaper route.

What about a turbo 400? I've seen those in lots of high powered cars down at the strips.

Well, it seems this box comes in several flavors in many cars.

https://kaizenfactor.wordpress.com/2...e-know-so-far/

https://i0.wp.com/cdn.mkimg.carview....1568e2cf9a.jpg
https://i0.wp.com/cdn.mkimg.carview....d87c9fd0aa.jpg
http://jpx.responsejp.com/jpx/images...jpg?fit=normal
http://www.ft86club.com/forums/attac...7&d=1324164055

I see the S15 listed there. I remember when that came out people were grenading them so I guess this box doesn't have a lot of extra beef in it. I see the Miatas seem to have got one, would that box be close?

http://www.barringtonperformance.com/images/miata1.jpg

This whole state of affairs concerns me. The rental that I test drove had a synchro going out so it seems like a forgone conclusion on that part. I beat the living crap out of a gearbox too so it's especially problematic. I will let Subaru swap boxes for me under warranty, but if somebody doesn't come up with an answer before that expires I am going to have a problem. Right now the repair parts are expensive, but is there likely to be secondary sources for the parts at some point?

TBH I am surprised there's no aftermarket (or at least specialist rebuild shops) for it yet.

Yeah replacement boxes are "cheap" but that's a band aid. Fortunately for me my box is getting smoother as the miles accumulate, and I occasionaly get some notchy shifts. I'm looking at the JRSC in the next year or so, and while its not crazy power and I consider myself a smooth shifter, I'd really like an alternative.

I swapped cryo'd RA gears into my shitty wrx 5mt and good lord, what a night and day difference. After grenading second on the stock box and reading about the similar problems people are having, I'll forever be wary of what subaru considers baseline/OEM quality. I recognize Aisin is not Subaru's go-to box, and probably was Toyota's recommendation, but still..

would be nice to see a stronger gearset available. I love how this transmission feels compared to the 5 and even 6mts from the EJ series subis.

That's a HUGE transmission and it's an auto.

There are ways of getting rid of that 2nd gear crunch. You can just switch out fluids. I switched over to Motul and I don't have that issue anymore. Made shifting even better than before.

ehhh.. motul is thicker at cold... actually motul's performance is worse cold than OEM. well documented here members have similar results.. the oil is great when temps get up to speed. I have it in my tranny, have had it in the past 7k miles

One of the prevailing techniques to avoid the crunch is to keep the car in 1st a little longer than usual, hang the initial start off to 3k rpms or so and hold it for a second or so before shifting. Has helped lots of others too :)

To be honest if you're on your third transmission in less than 20k miles and it's all been simply commuting to/from work and it's siezing up while just "driving in 6th gear at 70"... I don't want to sound rude, but that's pretty hard to believe.