Gearbox

The E30 was available as both a Manual and an Automatic. In total, seven different gearboxes were fitted to the E30; four manuals, all produced by Getrag, and three automatics by ZF.

The gearbox, prop-shaft and Differential make up the Transmission, and gearbox ratios are also dependent on the ratio of your diff. For example, a high ratio diff (4.27) combined with a high-ratio first gear (3.72) will make first gear useless. In contrast, a low-ratio diff (3.25) with a low-ratio gearbox (2.48 in first)

Gearboxes

Transmission gear ratios:

	4-speed manual	5-speed manual			3-speed automatic	4-speed automatic
available on	316, 318i	316, 316i, 318i, 320i	323i standard, 325i	323i sports	316, 318i	320i, 323i	325i
1st	3.76	3.72	3.83	3.76	2.48	2.73	2.48
2nd	2.04	2.02	2.20	2.33	1.48	1.56	1.48
3rd	1.32	1.32	1.40	1.61	1.00	1.00	1.00
4th	1.00	1.00	1.00	1.23	-	0.73	0.73
5th	-	0.81	0.81	1.00	-	-	-
reverse	4.10	3.45	3.46	4.10	2.09	2.09	2.09

Manual Gearboxes

All manual gearboxes were 5-speed with floor-mounted shifters.

Upgrades

Compatibilities

When upgrading the engine of your E30, you should also consider what effect this will have on the gearbox. When changing your M20B20 to M20B25, the gearbox is compatible, with the Getrag 240 gearbox of the former engine having similar ratios to the Getrag 260 Sports gearbox available for the latter. However, the 240 isn't as strong a unit, and may break prematurely.

The M42 engine mates up to the same gearbox used in M40 engines, but is not campatible with earlier M10 gearboxes due to the angle of installation, which will cause problems with the shifter and rear gearbox mount.

A Z3 short shift conversion will help you change gears quicker.