91GTX /w a HKS DOG

is the recommended 12k rebuild only if you beat the crap out of it(drag racing etc)?

Would a friction modifier like redline lightweight shockproof reduce the amount of gear grind in this tranny and extend its life? I know that this product helped me A LOT in getting rid of nudges/nutchy trannys and in some cases completely removed gear grind.

 

you should get rid of it and sell it to me...

 

I believe that the 12k service would be to check/replace the dogs from corner wear induced by not having close enough match between engine and shaft RPM at the point of engagement.

I would venture to say daily driving would be more likely to wear it faster as you are more likely to be distracted/lazy/skipping gears/unwilling to rev the loud car to proper rpm on downshift with that officer behind you.

Dog engaged transmissions want a relatively fast, deliberate shift with the engine and the selected gear at the same RPM.

My first '70 Honda car was dog engaged from the factory and it took a bit of driving to learn the gear spread and engagement. Early cars and all motorcycles are dog engaged, so you know it can be daily driven- it is just assumed the operator has some skill.

If you are the type that drives your regular synchro trans car without the clutch for fun or when the clutch goes out, you will have no problems getting the longer service life out of this transmission.

You should stick to a thick transmission oil as the manufacturer recommends. Probably 75w-90 and thicker. Ideally, you want something thick with a very high shock rating to cushion the dogs slapping against the ends of the slots for smoother operation.

 

So the most efficient way to drive it is to slam gears?

I would never get it in gear without the clutch , I don't understand how is this good for your tranny?

Redline has heavyweight shockproof.

 

I'm going to put pull it out as soon as I find S4 pieces to bolt a S4 tranny into an
S5 car, I havent driven it since it landed in Canada sorta scared to drive it on the streets

 

pretty much.

 

wait a second, you got dropped the money on a dog box and didn't know that?

why?

 

It's not about slamming gears. It's about matching the engine speed to the gear speed and engaging quickly.

People slam the gears, because they don't have time(race) or don't know how(street). To some degree the match will never be perfect, which is why the gears ever need to be rebuilt. Every time you shift you are damaging, to some degree, this transmission.

 

Car came this way from Japan.

I see a ton of FDs selling with dog boxes fully modded to around 500hp for 9-15k

 

I need help!

I thought a dog box was a synchromesh transmission but with straight cut gears as opposed to helical cut gears. Straight cut being stronger and without thrust loading. Is there one that treats the synchros different? Dogs instead of cones?

I'm confused.

 

You sir need to pm me if your looking to sell the HKS trans. need something to put behind my 20B for time attack.

 

So the most efficient way to drive it is to slam gears?

I would never get it in gear without the clutch , I don't understand how is this good for your tranny?

Redline has heavyweight shockproof.

The most efficient way (least damaging) to shift it is a relatively fast shift (faster than a synchro transmission is happiest shifting at) with constant and deliberate pressure at the point of contact between the dogs and grooves and you must have the engine and the selected gear at the same rpm.

It doesn't matter if you use the clutch or not. You just need to momentarily decrease the power to the transmission before you disengage the gear with a stab of the clutch or a lift of the throttle or pushing a button that retards timing. This is to get the undercut dog out of the slot.

It won't be that much easier on the transmission if you keep the clutch in as you engage the next gear or not as there is no synchro to cushion the engagement by matching the shaft speeds- YOU match the shaft speeds with timing and gas pedal.

If driving a regular manual transmission car without using the clutch and without grinding gears or making spooling syncho noises sounds daunting to you, you are in for a steep learning curve.

Redline heavy weight shockproof might be fine, but my experience with Redline oils is they have a low viscosity which won't be as good for softening the whack of the dog hitting the end of the slot. There is also a lot of empirical evidence that Redline does not lubricate the transmission bearings well.

Bottom line- use what the manufacturer recommends.

 

I need help!

I thought a dog box was a synchromesh transmission but with straight cut gears as opposed to helical cut gears. Straight cut being stronger and without thrust loading. Is there one that treats the synchros different? Dogs instead of cones?

I'm confused.

A dog box is like a regular synchro transmission where they remove the synchos assemblies and put in beefy dog and slot engagement.

A synchro assembly has a cone clutch to match speeds and slots in the circumference of the assembly to engage for power transmission while dog engagement is simply a dog and opposing slot on the faces of the gear assemblies which is much stonger and compact allowing more space for wider gears, bearing etc if used in same case as synchro trans or a more compact case (like motorcylce) if in an original dog engaged application.

Race applications will usually have straight cut gears as they have a larger tooth profile and put less thrust load on the transmission bearings/housing, but you can get them with helical or straight cut gears.

 

To make things even more confusing, the teeth on the gear that are engaged on a synchro transmission are called gear dog teeth.

 

so I unflooded my car and decided to test drive it, wow the tranny is pretty friggin loud and the straight turboback isn't helping with the noise either

No gear grind at all ! but apparently the previous owner turned something off cause I'm not even hitting .5 bar (boost controller and fcon are on..). However, evertime I shift, there is a hit as the engagement is hard, going to put in a stock T2 in a few weeks and maybe change the clutch, this one is worse than the following in terms of engagement and taking off: twin plate and, stage 3.

 

From what one of my friends was telling me... one of the worst things you can do with a dogbox is shift with the clutch. The shift collar and the gear rattle against each other and increase wear dramatically. To make it last the longest, shift quickly, firmly, and without the clutch, just unload the engine with a throttle lift or ignition cut.

And no matter what, all it can take is one misshift to screw up the dogs and you need to replace that collar and gear. That's why you used to see transmission replacement all the time in Group A rallying, before electronically shifted transmissions were made legal. No misshift = no dog problems.

Funny, those have been made illegal in WRC, so we'll probably start to see emergency 10-minute transmission replacements again

 

funny story; we were replacing the trans in the honda @the 2009 25 hours of thunder hill. as the new one broke something, and would actually pop out of gear with enough force that it was pulling the drive of the seat, after about half an hour.

anyways we were using the spare trans to hold down the easy up. so it was a little windy and while the trans held down the easy up just fine our photographer didn't! he got lifted off the ground and almost went for a ride!

 

You sir need to pm me if your looking to sell the HKS trans. need something to put behind my 20B for time attack.

 

Anyone else at asking if a DOGbox had DOGS in it instead of syncros?

 

i wouldn't drive it on the street, i have broke 2 hks now and 1 trust/quaife ( from excessive wear street driving) but using in anger at the strip they are fine, you would need the dogs looking at regularly and the box servicing if using in autox or t.a

hth

c