Chocolate syncro's on 6 speed gear boxes
#32
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Whats this talk with "beating" synchros guys?
I very nearly bought Ty's 6-speed out of his Spec-C, but it was gonna work out too much to realistically warrant it on
My classic. It would have been an ideal long term
Solution though. My existing 5 speed is hanging in there (original and running circa 330bhp), but its only a matter of time i think, it does get a lot of abuse when i drive the car. I do up and downshift very fast (habbit for motocross bikes and race quads) which i cant seem to get out of, so it wont be long. Im told te later gc8 sti gearboxes are good for my sort of power and should be stronger than mone atm? Id like to retain the close ratio's as much as o can cos i love 'em!
Rob
I very nearly bought Ty's 6-speed out of his Spec-C, but it was gonna work out too much to realistically warrant it on
My classic. It would have been an ideal long term
Solution though. My existing 5 speed is hanging in there (original and running circa 330bhp), but its only a matter of time i think, it does get a lot of abuse when i drive the car. I do up and downshift very fast (habbit for motocross bikes and race quads) which i cant seem to get out of, so it wont be long. Im told te later gc8 sti gearboxes are good for my sort of power and should be stronger than mone atm? Id like to retain the close ratio's as much as o can cos i love 'em!
Rob
#33
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For those that don't know, the reason I asked, and it really is a genuine question, is Max aka Hurst cars mentioned on another thread that he's had to replace the syncro's on two 6 speed gear boxes recently, so I just wanted to see exactly how many had experienced problems.
I'd actually like to discover that problems are few and far between or more a case of poor maintenance, which is probably most likely as not too many people get involved with their gear box until there is a problem.
There's plenty of info about 5 speed failures/problems but nothing much gets said about the 6 speed, now I know that's because generally speaking they are more reliable and can take big power.
I'd actually like to discover that problems are few and far between or more a case of poor maintenance, which is probably most likely as not too many people get involved with their gear box until there is a problem.
There's plenty of info about 5 speed failures/problems but nothing much gets said about the 6 speed, now I know that's because generally speaking they are more reliable and can take big power.
Dm, here are some answers as we see it. Consider this too; If ANYONE ever makes a gear oil that can fix dodgy synchro - they will make millions. You might mask a problem, it will not fix the underlying fault.
Any of the early 6 speeds - JDM or UK / Euro - suffer from knackering the viscous centre. It has a silly little thrust washer in one end that can be seen [ if it is still there ] when the centre diff is out. The locating tags are small and erode. Once eroded, the washers spins and destroys itself. that seem to allow movement inside the unit and the conical thrust washers drop out and the diff is scrap. You can get the viscous to bits just for the sake of looking, but once in bits they are never going back together again. It is just a learning exercise to see what's what.
Incidentally , no matter who or what, they cannot be "rebuilt" or "reconditioned". I researched it a year or so back and whilst mechanically you could make a good one out of several old ones, no one will advise what the spec of fluid is inside it is and no one can figure out - if and when you get the fluid - how to get it in there under pressure.
Anywhere up to 2007 [ pre Hatch ] the 4th,5th & 6th synchro rings are weak and have been replaced by a later version with a carbon coating on the grip surface. That fixes the problem.
BUT it is rare when a box is stripped, that there is no damage to the little 'dog ' teeth that the hub and ring use as engagement. So, if the teeth are damaged all 3 parts, [ gear , hub and ring ] need replacing. Doing part of it will never help, as the old damaged parts will damage the new part and the new part cannot ever repair the damage, however minimal, on the older parts.
Doing half the job is very short term.
We also find that the quietening pads on the selectors forks are worn away and they need replacing. Most folks can live with a bit of gear chatter from worn pads, but when they wear away completely the fork tends to twist when engaging gear and failure of some sort if imminent.
I have never seen a 6 speed gear with stripped teeth, they seem robust enough. We do have an input shaft from a 6 speeder that did nothing but 1/4 mile strip work and after a season of launches on a ceremetallic clutch and 559 hp there was a twist in the clutch spline in the shaft. Eventually it would have sheared off.
We are beginning to see damaged plates in Dccd type centre diffs and are having plate sets made that will be cheaper than the original parts, which are only available from Japan, [ as a repair kit at about £1300.00 + VAT or a new centre dccd at about £2700.00 + VAT ] The APi repair kit is expected to cost no more than £500.00 + VAT. GOOD advert eh ?
Individual gears are available from Subaru so in many ways, apart from the weight difference, a 6 speeder is a solution to many peoples transmission woes and is generally cheaper to repair than any of the PPG, Modena, types when replacement gears are needed.
When customers come in with a "cheap" box they have bought off the net or wherever, we usually expect to put 600- 700 quids worth of bits in to make them worthwhile fitting. Fitting an unknown quantity might mean it all has to come out again and have parts fitted which is plainly foolish. Boxes and kits that we sell have been rebuilt and are ready to fit with a warranty. [ another good advert.... ]
That's about it in a nutshell, David APi
#34
I really am genuinely curious about this as I think are many others and it's also not a subject that has seen much coverage, certainly not in the time i've been around, add to that most of the new age cars are getting on a bit now it's interesting to see what problems they get and helps everyone know what to look out for on the old girls.
Besides, you've been slacking a bit lately so someones got to liven the place up a bit.
Besides, you've been slacking a bit lately so someones got to liven the place up a bit.
#36
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I really am genuinely curious about this as I think are many others and it's also not a subject that has seen much coverage, certainly not in the time i've been around, add to that most of the new age cars are getting on a bit now it's interesting to see what problems they get and helps everyone know what to look out for on the old girls.
Besides, you've been slacking a bit lately so someones got to liven the place up a bit.
Besides, you've been slacking a bit lately so someones got to liven the place up a bit.
its too hot lately. I have heard the early boxes can give trouble as mentioned above but it seems on the whole the 6 speed is pretty robust, but as you say some of the early cars are now 10 plus years old so bad maintenance can be an issue as can abuse.
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My early 6 speeder(2002) is at 109k. Still has a nice gear selection with no crunches etc. Car is at 400hp and had plenty of launches and fairly hard use. Although it probably is over maintained.
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#46
[QUOTE=jayallen;11152968]It would have to be a pretty special New age STI to make me buy one and to be honest as a daily drive they are just not my cup of tea, and as a week end toy just not interesting enough or hard core enough, i'm not an everywhere at warp speed kind of guy, I get my thrills from the twitchy on the edge feeling that the type r gives, if I want to go fast i'd sooner do it on a 1000cc sports bike for a fraction of the cost. there aren't many cars that can stay with a gixer thou or a ZX12 R in a straight line on the open road up to 180mph, and I can get my hands on one for that extra £3k that the STI would cost me, which is a damm sight less than it takes to make a subaru do that.
I'm just too much of a tight wad.
I'm just too much of a tight wad.
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AND yes Steven seems to have no luck with boxes until recently.
Horses for courses and i think the Letral car is up there by the 700's for power.
Rather much to ask any 'standard' box to take.
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