Hilux Gearbox - Any Variants ( Mk1 , Mk2 ) ?

[Live Steam Mad]

After futher investigation, it would appear that the front end of this shaft is well supported with a Bronze bearing, and there is only the tiniest amount of play (side play) in the centre bearing when the shaft has it's front end supported. Hmmmn. Also I learned from the link above that the shaft and gears have to both be machined and chemically treated (apparently) in order to be able to re-assemble them after you have pressed them apart. In that case I am tempted to leave it and see how it goes.

BTW seller now accepts that he did not look in the gearbox and that I "may be right" about the spur gear having "some wear" on it. No $%^ ?!

Cheers,

Alistair G.

[robysoldtamiya]

The pinion is a special 10T gear. I try to explain: the spur gear is a 0.6 module gear, it means you can get one of your Sand Scorcher, F1, On road, Sand Rover, Manta Ray, TA01/02 and so on pinions and you'll find they will work with it. But if you'll ever be able to find a 10t pinion you'll find it will be too small, you have to find a 11T to have the good mesh.

The only reason I can think they made it this way is there is small material on a 10T 0.6 pinion to make it a press fit pinion and could easily broke, also they needed 10T to maintain reduction.

Same happens inside in both counter shafts: the small gears are both special gears, just look at the teeth and you'll find they will non look the same to all other gears.

Keep in mind that all gears of the tranny except main spur gear are 32p in hilux/blazer.

In Bruiser/Mounty everything is 32p.

[Live Steam Mad]

Your pinion is in extremely good conditions, don't worry about that.

Those teeth are particular because it is a 10 teeth built over a bigger radius than a normal 10t 0,5 module pinion.

Infact you can sobstitute this pinion with an 11T 0,5 module if you can find it.

Oh boy this is a bit of a problem for me to be able to understand it Yes OK I understand I think, but surely "10 teeth built over a bigger radius than a normal 10t 0,5 module pinion" would surely make the pinion is no longer 0.5 module and it's pitch has gone more coarse (larger "0.x" number in millimetres, than 0.5) to make up for it. Otherwise if it were still 0.5 pitch and a bigger radius, it would have more teeth! So it can't still be 0.5 module. Unless it was a lower pitch before like 0.4 module, and putting along a bigger radius would then make it e.g. 0.5 module. Very odd.

The pinion is a special 10T gear. I try to explain: the spur gear is a 0.6 module gear

I thought you just said that the pinion was 0.5 module. How could the spur then be 0.6 module? They wouldn't mesh, surely?

it means you can get one of your Sand Scorcher, F1, On road, Sand Rover, Manta Ray, TA01/02 and so on pinions and you'll find they will work with it. But if you'll ever be able to find a 10t pinion you'll find it will be too small, you have to find a 11T to have the good mesh.

Ahh, you are I presume meaning that SRB, F1, On road, Sand Rover, Manta Ray, TA01/02 all have the same pitch pinions ? And I assume you then mean that Hilux is the same pitch as those for pinion and spur?

The only reason I can think they made it this way is there is small material on a 10T 0.6 pinion to make it a press fit pinion and could easily broke, also they needed 10T to maintain reduction.

Same happens inside in both counter shafts: the small gears are both special gears, just look at the teeth and you'll find they will non look the same to all other gears.

Keep in mind that all gears of the tranny except main spur gear are 32p in hilux/blazer.

In Bruiser/Mounty everything is 32p.

OK I can kind of see what you are saying. Can someone clarify the whole of the above for me so that I can understand properly? I am getting a bit confused on how this works?

Cheers,

Alistair G.

[robysoldtamiya]

I really don't know why there is "0.6 module" almost everywere, I'm pretty sure I wrote 0.5 even when I read before posting.

Oh well I have to stop drinking this red wine bottles

[Live Steam Mad]

The spur gear is gone, the smaller gear I mean.

You're right there!!

But if you are handly you can use 18T 32p gears to rebuild it.

On the output shaft, what cause this problem is the single gear that is screwed on the cap. It runs with plastic bushing and often the nut get loose and the gear turns bad causing all 3 gears to worn out fast. You can still change these gears with 18T 32p gears.

Yeah, the 4WD output's "Counter gear", it runs on a pressed in plastic bush like you say. I will have to make sure that the nut on the outside of the case there gets Tamiya Liquid Threadlock'ed on properly. I checked mine and it's still pretty OK with reasonably fat teeth.

Other than that I see gears in nice conditions inside this tranny.

Roby

Yes, having taken a magnifying loupe to all of the gears, and having now accounted for what you told me about the design of certain of the gears where they are a 'lower number of teeth than expected on a larger radius', I can now see that they are quite OK for use, mostly nice fat teeth, with some wear in places but not bad at all really, except for about a 2mm width out of the approx. 8mm total width, along the edge of the teeth, on the outer edge of the "idler" gear (the one facing outwards on the rear main centre shaft), a 2mm section of it has the teeth worn to dagger like sharp triangles, but the rest of this gear for about 80 per cent of it's width is fine, so it's just the end that has been severely chewed, but by what is at the moment a mystery to me!

Synchro-mesh rings are fine as well (teeth I mean). Bearings seem to have some slop in them, but no more so than on an SRB, and it doesn't seem to be enough to create a cause for any gear stripping.

In a way I am thankful that the gearbox seems to be unpolished and the original version i.e. with Aluminium and Brass mixed gearing, I always like to feel that I have an original "1st edition" as it were LOL... Just a pity about the motor cover, it's crubling at the edges along the underside.

Cheers,

Alistair G.

[Live Steam Mad]

OK I thought that it would be interesting for those who have never looked inside one of these to see the shape of the gears (as they are a very strange cut on some of them). Also you can compare this to your own and see how worn mine is LOL.

And also I have a question about the shape of the teeth on the gears. Please can someone explain to me why the Brass gear's teeth on e.g. the first Countershaft (front gearbox half) are this curious shape that Roby told me about ?! I would appreciate an explanation from someone who really knows their stuff about gears and diametric pitch and the technical parts about gear teeth shapes etc.

The pictures below are of the first Counter shaft in the front gearbox half (which is the next thing in line in the drive train, after the motor pinion and then the plastic spur gear).

It's called the "2nd Speed Countershaft and Gear Unit", item #9 ;-

http://www.kope.com/bruiser/Exploded.pdf

(yes this is the Bruiser g.box but the Hilux one is very similar).

I am cleaning things up with White Spirit and taking pictures as I go.

BTW the seller now compensated me for the cost of a new Spur gear And the second gearbox arrived with a new spur gear in it (looks great, all teeth perfect on the spur) so I'm happy now.

Cheers,

Alistair G.

[Live Steam Mad]

Pictures of the gearing in the other Countershaft (the one in the rear gearbox half, labelled as item #10, "Low Speed Countershaft and Gear Unit") ;-

Again note the strange shape of the teeth on the Brass gear.

Cheers,

Alistair G.

[Live Steam Mad]

Pictures of the final 4WD front wheel drive output gear. Item #14, "Front Drive Shaft and Gear Unit" ;-

Thankfully conventional looking gear teeth here! Although it looks well chewed and mangled towards both ends of the teeth .

Cheers,

Alistair G.

[Live Steam Mad]

Pic's of the infamous gear that runs on the plastic bush which is the "idler" or "counter gear" before the final 4WD front drive output gear. It's called item #12, " Final Drive Countergear " ;-

Mine looks to be in fair condition, only mildly chewed

Cheers,

Alistair G.

[Live Steam Mad]

Here are pic's of the "new" Spur gear that was in the second gearbox that I am going to use for this 1st gearbox. You can compare it to the pic's on the 1st page to see the difference in wear! This one is practically new it seems ;-

Cheers,

Alistair G.

[Live Steam Mad]

Pic's of item #11, " 18T Idler Gear " ;-

Note that for about 2mm width out of the approx. 8mm teeth width it has been very heavy worn, you can see this by the shape (dagger like spikey teeth). The rest looks usable though.

Cheers,

Alistair G.

[WillyChang]

Somebody has been changing gear whilst on the move, or the shift servo isn't calibrated correctly to the gearbox.

Possibly both!

[Live Steam Mad]

Somebody has been changing gear whilst on the move, or the shift servo isn't calibrated correctly to the gearbox.

Possibly both!

Good point Wills, and I think I can see what has happened now. Someone (seller or person who owned it before he did) has been as you say shifting gears on the fly which has worn the heck out of the edge of the gear's teeth (2mm out of 8mm) by the Brass Synchro ring biting into it. I checked the Synchro rings and all 3 of them look OK on both sides thank goodness so it looks like the thing that has sustained the wear is this Aluminium gear since it is softer. Once the gear was very worn in 4WD mode and either stopped engaging properly or sounded horrendous when shifting gears, they have simply swapped this gear around so that it's facing the opposite way which means the teeth on that end are in perfect condition for engaging with the Synchro ring and hence 4WD worked properly again!

It's a pity that Tamiya did a "Crash gearbox" as it's called, instead of making the gearbox "Synchronised" (but I suppose using the cone shaped Brass clutches of such a gearbox would have added expense and complexity and be difficult to make to 1:10 scale). Also, spiral cut gears like a real 1:1 vehicle gearbox would have been nice, to increase strength via greater effective length of gear teeth, reducing wear, and also would make the gearbox quieter when running. With a Synchronised box, we could have shifted gears on the fly with very little wear and no horrid noises of a crash box. BTW some Mechano gears have even been made with spiral teeth so it can't be all that expensive to do, especially in these days of CNC and churn them out by the 1000's but I suppose this would have added some significant costs, back when these gearboxes were made and it was all done manually on lathes. Also BTW, Morris Minor gearboxes were also crash 1st gear if I remember right so even 1:1 cars did it on the cheap on occasion!

It also bugs me how Tamiya could have made the gears all out of Mild Steel, relatively free machining and relatively soft, and then case hardened them afterwards, as hardened steel is way harder than Brass or Aluminium. Why on earth Tamiya decided on Aluminium for gears is beyond me!

I was speaking to Jon an engineering friend that I know last night and he told me that the reason that the Brass gears have the teeth in that strange profile is that they are not that unusual they are just Involute cut gears (look it up on Wikipedia, it's interesting!) and the gears ROLL together instead of rubbing like on normal gears, and also they are done like that with very few teeth on the large radius so that each tooth has a large cross section and is very strong and resistant to torque, whilst allowing them to have a relatively higher gear reduction at the same time. I have to say that it must work as the teeth on the Brass gears which have this profile seem to have very little wear, whereas the conventional cut Brass gears like that one shown earlier above that runs in the plastic bush on the inside back plate of the gearbox has worn away significantly faster it seems.

PS. edited as I misunderstood how Synchromesh gearboxes worked LOL. Just learned from Wiki

Cheers,

Alistair G.

[twisty]

At the time these gears were cut,brass and alloy was much cheaper to do,it still is as far as i know.Problem is,most things are built to a price,the early 3 speed kits were IMO way ahead of thier time and very expensive.

When you see what is/was involved in creating such a beast you can see why they cost so much back when new in box.

Hard for the normal punter(so to speak) to see how a model car could be so expensive in a cardboard box,it only becomes more obvious when you actually lift the box and feel how heavy it is compared to what you thought and see the engineering involved.

Hows the gearbox going on anyway?

regards,

Simon F

[Live Steam Mad]

Hi, points understood and accepted. I have now cleaned nearly all of the gearing, you can see by the pic' below that I have put them in a bag to keep them clean until they get reinserted into the gearbox. Just working on cleaning the set of gears which is labelled as item #8 " Main Gear Cluster " on http://www.kope.com/bruiser/Exploded.pdf . You can see it to the right. It's a ****** to get clean as you can't separate the gears from each other, the 2 outer gears are locked to the shaft (probably on splines) with a tight press fit or something. Also the cleaned new Spur is in the bag.

That's where half my time goes, cleaning and restoring the parts before I can use them. That's what comes of building 30 year old models, you have to restore them first before you can even get to step 1 in the build manual Of course, rather that than buy the just about all plastic non-gearbox looking 3 speed gearbox that comes when you buy a HiLift or F350 or 1:14 lorry (truck). Oh hang on I already bought all 3 Euro trucks I love the look of the HiLift too. Just a shame about all that plastic...

Cheers,

Alistair G.

[WillyChang]

i was always told that spiral-cut gears aren't as strong as straight-cut gears, but they do run quieter & less chatter

spirals should also be run immersed in lubricant so their friction is minimised and the fluid conducts away the heat too

synchros only act to speed up or slow down gear clusters - you've forgotten there's also no clutch

Try changing gears on your 1:1 without the clutch... its possible, but best reserved for rental cars.

wouldn't be much benefit doing 1/10 synchro when you could just design one where all the gears are always spinning, like the semi's 3spd

Synchros also create friction when doing their work, so (1) they wear out and (2) best run immersed in oil.

Most pre-1960s cars didn't have synchros in 1st (and sometimes 2nd too) due to cost, only the fancy expensive marques do.

People learnt to DRIVE properly and match engine speed with the drivetrain, double-declutch etc.

Don't really need synchro in 1st as you're unlikely to change down into 1st whilst on the move too often.

[Live Steam Mad]

i was always told that spiral-cut gears aren't as strong as straight-cut gears, but they do run quieter & less chatter

Hi Wills,

According to Wiki the former point is not correct but the last 2 are.

To quote ;-

"The angled teeth engage more gradually than do spur gear teeth. This causes helical gears to run more smoothly and quietly than spur gears."

"With [parallel] helical gears, each pair of teeth first make contact at a single point at one side of the gear wheel; a moving curve of contact then grows gradually across the tooth face. It may span the entire width of the tooth for a time. Finally, it recedes until the teeth break contact at a single point on the opposite side of the wheel. Thus force is taken up and released gradually.

With spur [straight cut] gears, the situation is quite different. When a pair of teeth meet, they immediately make line contact across their entire width. This causes impact stress and noise. Spur gears make a characteristic whine at high speeds and can not take as much torque as helical gears because their teeth are receiving impact blows. Whereas spur gears are used for low speed applications and those situations where noise control is not a problem, the use of helical gears is indicated when the application involves high speeds, large power transmission, or where noise abatement is important. [..]A disadvantage of helical gears is a resultant thrust along the axis of the gear, which needs to be accommodated by appropriate thrust bearings"

and there is "a greater degree of sliding friction between the meshing teeth" with helical [spiral] cut gears".

synchros only act to speed up or slow down gear clusters - you've forgotten there's also no clutch

Quite so, I forgot about that, apparently the synchronised mechanism *relies* on a clutched gearchange, unless you manually very closely match the gear speeds to motor speed. That would be very difficult in 1:10 scale LOL.

wouldn't be much benefit doing 1/10 synchro when you could just design one where all the gears are always spinning, like the semi's 3spd

Synchros also create friction when doing their work, so (1) they wear out and (2) best run immersed in oil.

Points taken LOL.

Cheers,

Alistair G.

[hedge]

Good point Wills, and I think I can see what has happened now. Someone (seller or person who owned it before he did) has been as you say shifting gears on the fly

This was always the intended use. It was one of the main selling points of the 3speed changing gears on the fly. In fact once you start running it you will soon see that accelerating from low 2wd to high 2wd is by far the preferred method as opposed to starting in high 2wd.

However what was recommended then when parts where freely available vs todays second hand gearbox market might sway your descision.

PS the things are pretty freakin hard to control at top speed on all but the flatest surface and running in straight line

I would also urge you to look at the traxxas TQ3 3ch trigger grip conversion to complement your original 4 ch radio. Its fun, a bit technical (which I think you like) and IMHO a better gear change system than the 4ch shift gate.

http://www.rccrawler.com/forum/showthread....ghlight=tq3+mod

Cheers and Happy Christmas one and all.

Paul

[Live Steam Mad]

This was always the intended use. It was one of the main selling points of the 3speed changing gears on the fly. In fact once you start running it you will soon see that accelerating from low 2wd to high 2wd is by far the preferred method as opposed to starting in high 2wd.

However what was recommended then when parts where freely available vs todays second hand gearbox market might sway your descision.

Yes, in the Tamiya vintage Hilux video it does indeed mention that this is one of the main selling points i.e. on the fly gearchanging. Funny how the manual then seems to contradict this!

I would also urge you to look at the traxxas TQ3 3ch trigger grip conversion to complement your original 4 ch radio. Its fun, a bit technical (which I think you like) and IMHO a better gear change system than the 4ch shift gate.

OMG do you mean a wheel and trigger TX? I got one with my Gallop MK2 and it's the most awful thing I have ever used. Completely counter intuitive. At 34, being brought up on sticks, I cannot go to wheel TX's. Or did you mean a conversion for a twin stick TX?

PS you are right about me liking technical stuff

Cheers,

Alistair G.

[hedge]

OMG do you mean a wheel and trigger TX? I got one with my Gallop MK2 and it's the most awful thing I have ever used. Completely counter intuitive. At 34, being brought up on sticks, I cannot go to wheel TX's. Or did you mean a conversion for a twin stick TX?

PS you are right about me liking technical stuff

Cheers,

Alistair G.

LOL I can't stand wheel/trigger TX for racing, its sticks all the way, but at the gentle speed at which these trucks miander its simple enough to use a steer wheel. The benefit is the gear change mechanism its a three way toggle switch (2wd high, 2wd low, 4wd which you must install) and it allows very fast changes between 2wd slow and 2wd fast all the way back to 4wd, simply better than a shift gate IMHO.

Merry Christmas

Paul