drive model. 1995 saw the introduction of the X20XEV Ecotec engine, a new version of the classic C20XE 16 valve or "red top" engine. This marked a reduction in power from to for the 16 valve version, although the Turbo continued with the C20LET. 2.0 litre 8 valve SOHC I4 – (all years) (C20NE) 2.0 litre 16 valve DOHC I4 – (1990–1995) (C20XE or redtop) 2.0 litre 16 valve DOHC Ecotec I4 – (1995–1997) (X20XEV) 2.0 litre 16 valve DOHC turbocharged I4 – (1992–1997) (C20LET) 2.5 litre 24 valve DOHC Ecotec V6 – (1993–1997) (C25XE from 1994–1996; X25XE in 1997) The availability of engines is dependent on specific modellvariants, accessory levels and domestic markets. Technical data Transmissions In addition to the Aisin four-speed automatic transmissions that were available on all models, except the C20LET (although some countries such as Australia did not sell the C20XE with the four-speed auto), there were five manual gearboxes produced by Getrag (all of which were five speed gearboxes, except the six speed F28/6). F16CR-5 – Fitted to early 2.0 litre SOHC NA (i.e. C20NE) F18CR-5 – Fitted to late 2.0 litre SOHC NA and late 2.0 litre DOHC NA (i.e. C20NE, X20XEV) F20 – Fitted to early 2.0 litre DOHC NA (i.e. C20XE) F25 – Fitted to 2.5 litre NA (i.e. C25XE, X25XE) F28/6 – Fitted to 2.0 litre Turbo (i.e. C20LET) AF20 – Fitted to late 2.0 litre SOHC NA and late 2.0 litre DOHC NA (i.e. C20NE, X20XEV) and 2.5 litre NA (i.e. C25XE, X25XE) The transfer gearbox in the AWD models — the same as used in the Vauxhall Cavalier AWD—was somewhat on the flimsy side, liable to suffer damage from conditions such as minor differences in tyre wear or tyre pressure between front and rear axles. Since front and rear tyres would naturally wear at different rates in normal driving, it was necessary to swap front with rear tyres every - recent user recommendations propose 3,000 miles (5,000 km). All four tyres had to be of the same make and model, and all four tyres had to be replaced at the same time — if one tyre was damaged or punctured, the three remaining good tyres also had to be replaced. In addition there were other maintenance requirements which were both exacting and unusual. Neglect of these points through ignorance or a misconceived attempt to save money was common, and