Fitting an e36 gearbox to a e30 318i

[Pontyleeroy]

Iv purchased an e36 gearbox from a 318 for its lower ratios and would like to know what issues there are with fitting this box to a e30 318i? Thinking of swaping them this weekend, Is this swap a straight forward job? Your information will be greatly appreciated. Thanks.

[Pontyleeroy]

Well I have carried out the box swap and realised from my own experience a couple of mods needed for this job. The e30 gear linkage fits the e36 but needs to be shortened by 10mm, The e30 rubber guibo needs to be drilled out to 12mm to match the e36 box bolts, but what has puzzled me is why the prop centre bearing housing doesn't line up with the holes on the car? I know the e36 box is longer but from reading other threads I haven't heard of this? can anyone tell me why or what prop should be used?

[Motorhole]

May need the e36 318i prop and guibo too. E30 centre bearing may fit with the E36 prop, if not, fitting it backwards might give a few more mm adjustability. Can't confirm any of this from experience though! But the general gist is, you want to be fitting the prop from whatever car donated the 'box...

[DanThe]

You cant fit the centre mount backwards, it only fits the body one way. If you do fit it backwards and manage to bolt it up the prop shaft will not be straight. The centre mounts are body specific, early prefacelift cars had a different mount to later cars, E36 mounts are very different.
The E36 Getrag box's used an output flange the same size as most E30's but with M12 bolts rather than M10, Ideally you use E36 donut and prop to match, if you must use an E30 prop then drill the bolt holes out to 12mm so you can use the correct bolts, I wouldnt be drilling the donut though

[Pontyleeroy]

Cheers boys. I'll try and get my hands on a e36 prop and offer it up. I have read in the e30 wiki that there is a shorter prop fitted to the 318is. Both 318i n 318is have the same box in shape n size just 3rd is a lower ratio in the IS box. But to fit a 318i gearbox to a IS you also must swap the prop. The output shaft on a IS sticks out further, hence why I'm thinking the prop is shorter. Would anyone know the length of the front half of a 318is prop?

[Pontyleeroy]

Instead of spending money on all different props to offer up, I took my original prop down to "Bar Props" and had it shortened by 23mm and balanced for only £50. Problem solved. But nothing is straight forward, put oil in my gearbox to find it dripping on me. Only a crack along side the exhaust mount casting. Luck isn't on my side.