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Type 9 gearbox and Sierra diff fixed to chassis so no axle movement.

Going to position gearbox mounting holes today. How much play should there be back to front when prop shaft goes into gearbox tail ?

Just perceptible? An inch ?

The sliding joint at the gearbox end takes up any tolerance in the setup and will compensate for any movement in the system during use.

Steve

Yes I know Steve but when I shove the splined bit into the gearbox, do I shove it hard in as far as it will go or do I leave some room for eg expansion, chassis,engine mount flexing or whatever ?

Position is, I have the diff fixed, and the propshaft attached. now I have to trial fit the gearbox (with the appropriate play) so I can drill the gearbox mounting holes.

[Edited on 14/11/07 by Macbeast]

I believe a good rule of thumb is ......

shove it in all the way, pull back 1 inch.

But i've no idea where i've got that idea from so wait for someone else to comment before you weld brackets.

do you have a rubber donut? or two UJs?

in all the way, then pull out an inch was what I did. You only need to account for the engine movements on the rubber mounts so 25mm of end float would be plenty.

I thought I posted a reply to this at 04:30 this morning. Obviously i failed to complete, god knows why.

Any way I went out to the garage (at 04:20) and measured the spare/clean section of the propshaft nose sticking out from the gearbox tail. 20mm was the answer. Thats a new propshaft made from the measurements taken from end of gearbox to the diff flange then supplied to Bailey Morris. If 20mm is good enough for them then it should be good enough for you.

20mm.


enjoy

You want as much spline as possible engaged in the gearbox so there is no risk of the spline bottoming out and so you can fit the prop.

As has been stated, in practice this means push in all the way and pull out 20mm to 25mm.

I built thousands of propshafts and that is the dimension we used.

quote:

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Originally posted by MikeR
I believe a good rule of thumb is ......

shove it in all the way, pull back 1 inch.

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Ok 20mm it is then

Many thanks to all, especially JGG for the early-morning penetration check

Oh and Ben - if I did that it would fall out

[Edited on 14/11/07 by Macbeast]