Gearbox Input Shaft Protrusion

[Drewmotty]

I’ve just finished rebuilding my TR4 gearbox and noticed that when I stood it on its bell housing for temporary storage that the input shaft doesn’t protrude beyond the bell housing. 
The TR6 gearbox in my TR3 and the original TR3 3 synchro box both need to be stood on blocks of wood to avoid the input shaft hitting the floor. 
Can anyone shed any light on this?

[RogerH]

Hi Andrew,

 that is odd. Does it stick out the back further than normal

 

Roger

[rcreweread]

As I understand it, input shafts on early TRs were "long" and stuck out beyond the bellhousing, hence gearboxes would not stand on end fully upright - I might be wrong but I have a feeling they changed to a "flush" one when the "thick rimmed" bellhousings were introduced later on in the TR4 production.

The "long" bit is only the round machined tip which fits into the bush in the crank/flywheel and if you are fitting a gearbox with a long tip input shaft into a later short tip car, you just need to cut off the difference, about 10mm I think.

AFAIAA, nobody quite knows why ST changed the shafts, but it is speculated that they did so to stop gearboxes falling over in the factory!

Cheers Rich

[stuart]

On 4/24/2021 at 7:54 PM, rcreweread said:

 

 you just need to cut off the difference, about 10mm I think.

 

 

No you dont, they both fit.

Stuart.