Layshaft vs no layshaft

[VMJYogi]

I'd like to know if there are manual transmissions with no layshaft. EX. the input shaft would have gearing on it and the driveshaft would be directly above or below the input shaft with no need of a layshaft. Has this been done? Is it still done? If not wouldn't it be a good idea to try it? What would be the problems with said tranny?

[88GrandPrixSE]

Originally Posted by VMJYogi

I'd like to know if there are manual transmissions with no layshaft. EX. the input shaft would have gearing on it and the driveshaft would be directly above or below the input shaft with no need of a layshaft. Has this been done? Is it still done? If not wouldn't it be a good idea to try it? What would be the problems with said tranny?

Do you mean the driveshaft would have gears on it...? Because that'd be the only way to transfer the power to the driveshaft from the input shaft.. If that's what you're saying, well, it has been done, it is done, but only on small applications. ie: 2 speed R/C cars. But in the real world, never been done to my knowledge. There'd be loads of problems with something like that, like there'd be no oil to cool it/lubricate it so it would wear and over-heat very quickly.

[shulle3]

The layshaft you refer to is actualy a countershaft. and no it would not work without a countershaft. wouldnt be able to get reverse without an idler off of the countershaft so no you cant have one without a layshaft(countershaft).

[VMJYogi]

Couldn't you have an idler off of the input shaft directly onto the driveshaft? And yes there would be gears on the driveshaft. and the oil system could relatively be the same. if you look at how mnual transmissions work on howstuffworks.com u'd see what i was askin if ur confused as to my question. Go to http://auto.howstuffworks.com/transmission5.htm and look at the second picture down. Now imagine that the green shaft and gear are removed from the equation and instead the red shaft extended further to the left to the engine. I know u'd have to change the gear ratios around but could it work?

[ChrisV]

Actually yes, it could easily work in that example, as often that first gear ratio over to the second shaft is a 1:1.

The reason it's done the way the diagrams have it is to center the output shaft (and thus the driveshaft) with the input shaft. it gives a nice line of torque through the transmission. and so al lteh parts spin in the correct direction (doing it your way would reverse the spin of the driveshaft in relation to the engine)

But, either way, there's still two total shafts in the transmission, so you're really not gaining anything.

[VMJYogi]

Hey i see!! Thanks.