How to treat the gearbox?

 

 

The lifespan of a gearbox depends on how it has been used during its life. It’s a simple as that. If the box get’s noisy, or goes kaput, 9/10 it’s your fault only or/and the car’s user before you, in the case if it is a used car.

If you’re buying a used car and you stumble upon a car with a sloppy stick, noisy changes and whining driving, simply don’t buy that one. If the gearbox has been treated that bad, how are the rest of its mechanics been used and how well have they been maintained, if maintained at all.

Many times when the car is out of it’s warranty-period, people seem to “forget” the maintenance because it’s too expensive.    

 

Keep the following points under consideration and the lifespan of your gearbox will be significantly extended. Starting with the worst:

 

·         Do change oil regularly.

Though practically no manufacturer advises an oil change for their gearboxes at all, they simply state its oil is holds for a lifetime. Why this is I have no clue, because there’s always synchromesh wear -where the debris eats in the gasket seals-, water can come in through its ventilation on the top, and there’s always the leakage along the drive axles seals and between gearbox half shells.

Leakage is the biggest gearbox killer; since there are only a few litres in there and a leakage of a few drops a day over several years is enough to loose too much oil from the ‘box to still function properly. But before it is empty the fifth gear’s needle bearings will give the ghost because of lack of lubrication, due to the fact the fifth is positioned ‘outside’ the actual gearbox. It gets just enough lubrication when the oil is on level, but only gets oil by chance if the level is only a bit -say half a litre- under it. Long lefthanders don’t do any good either, in that case. Hot, thin oil on long drives neither. And if there’s water in the oil it will become *very* thin, since it will start to foam in that case!

So, check the level -or have it checked- at every engine oil change. Don’t listen to the ‘sealed for life’ guarantees from the professionals or people who think they know.

It’s as simple as undo the level plug and eventual fill up until it refluxes. Leave it running out until it stops dripping and put the plug back with a new seal ring. Otherwise you are ‘carrying water to the sea’. Go cheap on the ring and it is better not to check at all, because the plug will start to leak as a fishnet!

A gearbox oil change (which normally costs max €100/$160 if done at the dealer) should be done every 60-100,000 km. Keep at least to the advised grade stated in the manual, but a known brand full-synthetic is better. Stick to the normal ones, not the friction reducing crap. Same story for add-ons: don’t: the PTFE used in for example Slick50 causes the metal debris to continuously float around in the oil instead of it getting caught by the magnet fitted in every gearbox (sometimes on the end of the drain plug, sometimes in the box itself). Plus a worn box cannot be fixed by add-ons. It simply needs an overhaul.      

 

·         Secondly, avoid jerky power changes, such as clutch-drop launches and full throttle accelerations followed by sudden idle (full deceleration) repeatedly.

Though for some it’s incomprehensible that a gearbox can’t handle this abuse (“a WRC car can do that too” failing to understand it has a straight-cut purpose-build ‘box that, even though it’s supposed to be bullet-proof, lives for two rounds only), so they claim that “my ‘box is crap” after they themselves totally wore out each and every single mechanical part in the gearbox…

Hopefully you can now make your own opinion next time you hear a story like that. 

 

·         Avoid fast gear shifts, especially in combination with short-shifts.

Largely like the above, since a road ‘box is not a straight-cut dog ‘box, it’s made for comfort and actually has something called synchromesh rings to make the gearshifts smoothly and noise-free (ever hear a dog ‘box engage 1^st gear?). The best way to shift gears is to “slowly” pull it out of gear and hold it against the next gear until the gearbox’ synchromesh has done its work and the lever almost gets “sucked” into gear.

A good gearbox manages this in half a second, so it’s not going cause you to miss your dinner.  

 

·         Avoid shifting diagonally when making a change from (for example) 3^rd to 2^nd. Use a square movement following the H-shape as pointed out on the lever. Mechanically this is how it’s supposed to be done and if not, the levers and the internal shifter-forks and its shifter-rail will wear unnecessarily. Over time this will show as a sloppy, gutless lever and when it becomes excessive it will be impossible to shift into reverse and/or 5^th.

 

·         Don’t put your hand on the shifter when you’re not changing gears. Basically for the same as above. Unnecessary wear on the mechanics and especially the gear used as the armrest gear, which is normally the fifth.

 

·         Also under the chapter "bad habits"; don't rest your foot on the clutch pedal either. This will keep the clutch’ thrust bearing unnecessarily engaged over long periods and it simply cannot cope with that. It's a bit of a waste to have a big operation like removing the gearbox from the car, just to renew the clutch bearing.

 

·         Last but not least; do treat the clutch with respect. Fully depress the clutch pedal with each and every shift. As with gearboxes, there is a significant difference between race and road clutches. The first is made for (again) comfort, so even your granddad can drive you car and for mechanical preservation. A road clutch plate is made with a centre part (attached to the gearbox) and the outer part with the friction material (connected -when the clutch is engaged- to the flywheel of the engine and the two are separated by springs fitted in a radial fashion around the clutch’ centre. These springs help to isolate the transmission from the shock of the clutch engaging. All the forces go through these springs. The more you “launch”, the more you abuse the springs (apart from nearly every other single mechanical part of the drivetrain). There are also waved sheet-springs between the front and backside of the clutch’ outer plates, under the friction material. These are fitted to progressively engage the clutch, just help you not to stall the engine. A race clutch is one pieced, purely made to get the torque from A to B, no build-in comfort at all. That’s one reason why it’s much easier to stall an engine when trying to drive off, if the engine’s fitted with a race clutch. Long story short; if you don’t have one fitted, don’t treat the standard clutch like a race clutch and stop imitating what you see on TV.