Jump to content
SAU Community

Recommended Posts

Shifting into 2nd is a bit 'stiff', 'clunky', also down shifting into 1st.

Doesn't make a difference if vehicle is well warmed up.

What does that mean? Gearbox knackered? I think my clutch is ok.

What's the $ to sort this if it is the gearbox?

Link to comment
https://www.sau.com.au/forums/topic/285719-gearbox/
Share on other sites

Synchros are worn mate, nothing much you can do. Changing gearbox oil will help MASK the problem but it won't ever be fixed. Either get a new gearbox or freshen up your current one

What's the rough cost of say rebuilding my current one? Can you just buy new synchros?

Link to comment
https://www.sau.com.au/forums/topic/285719-gearbox/#findComment-4797037
Share on other sites

Need to recondition the thing with new synchros. Will cost about $1000-1200 with you taking the box out.

Why are you downshifting into 1st? Unless the car is at a stop you shouldn't be putting the gearbox in 1st. It'll just wear out your 1st gear synchro something bad.

Link to comment
https://www.sau.com.au/forums/topic/285719-gearbox/#findComment-4797200
Share on other sites

at $1200 + labour ($300-400 for labour?) ...how much is a new gearbox ?

never mind ..found an R33 genuine nissan from a popular jdm sho in sydney (ie. exxy shop) for $3200 ..so I'm guessing it should be doable for $2500 or so.

Link to comment
https://www.sau.com.au/forums/topic/285719-gearbox/#findComment-4797248
Share on other sites

Need to recondition the thing with new synchros. Will cost about $1000-1200 with you taking the box out.

Why are you downshifting into 1st? Unless the car is at a stop you shouldn't be putting the gearbox in 1st. It'll just wear out your 1st gear synchro something bad.

I mean going into 1st when still rolling, not then engaging the clutch as such, but keeping the clutch out until stopped and ready to move off again after say the lights change. Is that a no-no? Damn I've been driving like that for years. :)

Anyway I just was wondering if I get the gearbox rebuilt that would be worn syncros, seal and bearings? right? Is there any disadvantage to doing that over getting a 'new' box (which would just be one from a wreckers right? so low km?). I don't need an 'upgraded' gearbox since my car is stock and even though I'm planning some mods I doubt I'll get more that 200 kw at the wheels since I'm not planning on anything more that stage 1 (ish).

I mean I can live with it since the car still drives ok(ish). But it's just a niggling thing that isn't going to get better then and is kinda annoying to be honest.

Link to comment
https://www.sau.com.au/forums/topic/285719-gearbox/#findComment-4797375
Share on other sites

have you considered draining your gearbox oil and putting in some Redline Shockproof Lightweight oil instead ? So many people swear by it ... as it 'masks' all the existing problems with your gearbox ie. worn syncros. So it feels as new until it completely dies I guess ..which could be in 10 years time, long after you've already sold/crashed/written off the car.

I have the same notchy feeling, especially on cold starts ... so I'm gonna try this shockproof oil soon. Don't see the point in reconditioning gearbox as I'm not gonna take my car over 200rwkw anytime soon. For $100 I can get the same feeling as new/recon box :)

Link to comment
https://www.sau.com.au/forums/topic/285719-gearbox/#findComment-4797429
Share on other sites

redline shockproof is from what i hear not good for syncros or not approved for use with sychro gearboxes

Best I could figure out is that the Shockproof oil is good for worn boxes with synchro issues etc ie. any 10+ year old car. On a new/reconditioned box you would use the normal oil (MT90 or whatever it is)

Link to comment
https://www.sau.com.au/forums/topic/285719-gearbox/#findComment-4797548
Share on other sites

at $1200 + labour ($300-400 for labour?) ...how much is a new gearbox ?

never mind ..found an R33 genuine nissan from a popular jdm sho in sydney (ie. exxy shop) for $3200 ..so I'm guessing it should be doable for $2500 or so.

Is that a brand new gearbox you found or a second hand import? If it's second hand that's a rip off IMO. If brand new it sounds about right / worthwhile.

I mean going into 1st when still rolling, not then engaging the clutch as such, but keeping the clutch out until stopped and ready to move off again after say the lights change. Is that a no-no? Damn I've been driving like that for years. :D

Anyway I just was wondering if I get the gearbox rebuilt that would be worn syncros, seal and bearings? right? Is there any disadvantage to doing that over getting a 'new' box (which would just be one from a wreckers right? so low km?). I don't need an 'upgraded' gearbox since my car is stock and even though I'm planning some mods I doubt I'll get more that 200 kw at the wheels since I'm not planning on anything more that stage 1 (ish).

I mean I can live with it since the car still drives ok(ish). But it's just a niggling thing that isn't going to get better then and is kinda annoying to be honest.

I recommend waiting until the car is stopped, or atleast around 5km/h. The synchros match vehicle speed with gear speed, working somewhat independantly of the clutch. I'm not saying "you can't do this, blah blah", I'm just saying that this is what wears out your synchros. They are a wearing, serviceable item just like any other mechanical part of the car. And it's always a balance between how hard you want to drive your car and how long it lasts :)

A full and proper gearbox recondition will have all the worn synchros, seals and bearings replaced. I highly recommend doing this over buying a second hand box, as the process leaves the box refreshed in an as new condition. The only disadvantage is on some really worn/old boxes you can be left with a slight rollover bearing noise in neutral, which comes about after resetting gearbox tolerances. Second hand boxes in general are cheaper, but it's lucky dip whether you get a good one and most places won't offer you a warranty on them. Some last 1000km, others last 100,000km. Also remember that the car went to the wreckers for a reason and it's not uncommon for accident damage to have an impact on the gearbox. This is just my opinion - not everyone has a spare grand or two to get their gearbox reconditioned.

have you considered draining your gearbox oil and putting in some Redline Shockproof Lightweight oil instead ? So many people swear by it ... as it 'masks' all the existing problems with your gearbox ie. worn syncros. So it feels as new until it completely dies I guess ..which could be in 10 years time, long after you've already sold/crashed/written off the car.

I have the same notchy feeling, especially on cold starts ... so I'm gonna try this shockproof oil soon. Don't see the point in reconditioning gearbox as I'm not gonna take my car over 200rwkw anytime soon. For $100 I can get the same feeling as new/recon box :D

No harm in trying the stuff on a worn box, it probably does wonders (have no experience with it myself), but you are correct in guessing it masks the problem and it will be an unfortunate surprise for the next owner :)

For the record guys, synchro wear doesn't have much to do with the power your engine is putting out...it has more to do with your style of driving; type of clutch; how fast/slow you change gears. Power/torque is more likely to strip or blow the gear itself. If you want to preserve synchros, avoid changing down at high RPM, double clutch when appropriate and don't slam the thing into gear. A smooth, positive shift is a fast shift anyway.

Link to comment
https://www.sau.com.au/forums/topic/285719-gearbox/#findComment-4798175
Share on other sites

on that note .. maybe some shockproof lightweight + one of those ebay shortshifters would be a good idea? You get easy shifts due to oil and you can shift faster without damaging the synchros any further since it's a much smaller throw to put into gear ?? That way your worn/factory box will last as long as possible AND feel great... Just an idea :thumbsup:

Link to comment
https://www.sau.com.au/forums/topic/285719-gearbox/#findComment-4798808
Share on other sites

Well actually, those short shifters usually only change the pivot point (and therefore the throw) of the gear shifter...the synchros still travel the same distance to engage. Short shifters alter the balance between ease of gear shift and speed of gear shift, much like closing a door by pushing on a part closer to its hinges rather than using the handle. Thus making it worse for the synchros because more physical force is required on the shifter to change gears...and across a shorter throw...making for a harsh and not-so-smooth shift. Nice try though :thumbsup::D:(

I really should go home.

Link to comment
https://www.sau.com.au/forums/topic/285719-gearbox/#findComment-4798930
Share on other sites

I get what you're saying but I woulda thought a short shifter would allow you to shift without missing a shift ..where most of the crunching is done and damage to synchros. ie. with a short shifter you could still shift SLOWLY but it wouldn't be such an annoyance as the throw is shorter... ah well, just an idea albeit a pretty weak one :laugh:

Link to comment
https://www.sau.com.au/forums/topic/285719-gearbox/#findComment-4798970
Share on other sites

Took the car to a mech and he took it for a blast around the industrial estate (literally, I'm glad no cops were lurking about :laugh: ) Reckons syncros aren't worn too bad, but maybe a tooth has been knocked off here and there making a few shifts clunky on occasion. His advice is to change the oil to something more suitable (not sure what), probably not worth a full rebuild. Anyway I'm gonna take it in to do that if a couple of weeks and also get them to check the whole car over for EVERTHING. The guy could easily have told me to do a rebuild. Had a chat about light mods (exhaust, inflow) and will probably do that after he goes over the whole car.

Link to comment
https://www.sau.com.au/forums/topic/285719-gearbox/#findComment-4799132
Share on other sites

Just wanna point out the difference between reconditioning and rebuilding, with the latter involving the replacement of every component in the gearbox (including the gears) for brand new parts. It is an unnecessary and overly expensive process, because gears themselves only break with excessive torque or driver abuse. Reconditioning involves only replacing the worn items plus all the bearings and seals. It is much cheaper and realistically what you would get done if you had the cash / wanted to fix your synchro problem for good.

Link to comment
https://www.sau.com.au/forums/topic/285719-gearbox/#findComment-4799461
Share on other sites

  • 1 month later...

My R33 GTS-t has pretty much the exact same symptoms as you have just described. i have been thinking about the above options and recon ill look to get it reconditioned. looking to eventually push at least 250 kw atws out of it by the time if finished doing it up so i recon a strong drivetrain will be the best place to start. at the moment it is 100% stock except for a pod filter.

anyone know any good gearbox places in adelaide? preferebly once with experience in working with these gearboxes???

Link to comment
https://www.sau.com.au/forums/topic/285719-gearbox/#findComment-4865590
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Thanks for the reply mate. Well I really hope its a hose then not engine out job
    • But.... the reason I want to run a 60 weight is so at 125C it has the same viscosity as a 40 weight at 100C. That's the whole reason. If the viscosity changes that much to drop oil pressure from 73psi to 36psi then that's another reason I should be running an oil that mimics the 40 weight at 100C. I have datalogs from the dyno with the oil pressure hitting 73psi at full throttle/high RPM. At the dyno the oil temp was around 100-105C. The pump has a 70psi internal relief spring. It will never go/can't go above 70psi. The GM recommendation of 6psi per 1000rpm is well under that... The oil sensor for logging in LS's is at the valley plate at the back of  the block/rear of where the heads are near the firewall. It's also where the knock sensors are which are notable for 'false knock'. I'm hoping I just didn't have enough oil up top causing some chatter instead of rods being sad (big hopium/copium I know) LS's definitely heat up the oil more than RB's do, the stock vettes for example will hit 300F(150C) in a lap or two and happily track for years and years. This is the same oil cooler that I had when I was in RB land, being the Setrab 25 row oil cooler HEL thing. I did think about putting a fan in there to pull air out more, though I don't know if that will actually help in huge load situations with lots of speed. I think when I had the auto cooler. The leak is where the block runs to the oil cooler lines, the OEM/Dash oil pressure sender is connected at that junction and is what broke. I'm actually quite curious to see how much oil in total capacity is actually left in the engine. As it currently stands I'm waiting on that bush to adapt the sender to it. The sump is still full (?) of oil and the lines and accusump have been drained, but the filter and block are off. I suspect there's maybe less than 1/2 the total capacity there should be in there. I have noticed in the past that topping up oil has improved oil pressure, as reported by the dash sensor. This is all extremely sketchy hence wanting to get it sorted out lol.
    • I neglected to respond to this previously. Get it up to 100 psi, and then you'll be OK.
    • I agree with everything else, except (and I'm rethinking this as it wasn't setup how my brain first though) if the sensor is at the end of a hose which is how it has been recommended to isolate it from vibrations, then if that line had a small hole in, I could foresee potentially (not a fluid dynamic specialist) the ability for it to see a lower pressure at the sensor. But thinking through, said sensor was in the actual block, HOWEVER it was also the sensor itself that broke, so oil pressure may not have been fully reaching the sensor still. So I'm still in my same theory.   However, I 100% would be saying COOL THE OIL DOWN if it's at 125c. That would be an epic concern of mine.   Im now thinking as you did Brad that the knock detection is likely due to the bearings giving a bit more noise as pressure dropped away. Kinkstah, drop your oil, and get a sample of it (as you're draining it) and send it off for analysis.
    • I myself AM TOTALLY UNPREPARED TO BELIEVE that the load is higher on the track than on the dyno. If it is not happening on the dyno, I cannot see it happening on the track. The difference you are seeing is because it is hot on the track, and I am pretty sure your tuner is not belting the crap out of it on teh dyno when it starts to get hot. The only way that being hot on the track can lead to real ping, that I can think of, is if you are getting more oil (from mist in the inlet tract, or going up past the oil control rings) reducing the effective octane rating of the fuel and causing ping that way. Yeah, nah. Look at this graph which I will helpfully show you zoomed back in. As an engineer, I look at the difference in viscocity at (in your case, 125°C) and say "they're all the same number". Even though those lines are not completely collapsed down onto each other, the oil grades you are talking about (40, 50 and 60) are teh top three lines (150, 220 and 320) and as far as I am concerned, there is not enough difference between them at that temperature to be meaningful. The viscosity of 60 at 125°C is teh same as 40 at 100°C. You should not operate it under high load at high temperature. That is purely because the only way they can achieve their emissions numbers is with thin-arse oil in it, so they have to tell you to put thin oil in it for the street. They know that no-one can drive the car & engine hard enough on the street to reach the operating regime that demands the actual correct oil that the engine needs on the track. And so they tell you to put that oil in for the track. Find a way to get more air into it, or, more likely, out of it. Or add a water spray for when it's hot. Or something.   As to the leak --- a small leak that cannot cause near catastrophic volume loss in a few seconds cannot cause a low pressure condition in the engine. If the leak is large enough to drop oil pressure, then you will only get one or two shots at it before the sump is drained.
×
×
  • Create New...