In terms of their physical external design, VW used 6 types of manual gearbox in the ’68 – ’92 rear engined models. There are many different gearbox codes for each, denoting different internal specs (usually different ratios):

VW Gearbox Type:Gears:Dates:Engines used with::Notes:Gearbox code location:
0024 + R1968 – 19791584, 1679, 1795The bus gearbox for all ‘1600’ Bay / T2a / T2b models
091 Bay / T2b4 + R1975 – 19791970Stronger ring and pinion than 002, often more desirable final drive ratio than 002, shift rod on gearbox centreline pointing forwards, often referred to as the ‘6 rib’ ‘box, although this causes confusion
091 T25 / TT3 / Vanagon4 + R1980 – 19831970 Petrol, 1588, 1709 DieselNot interchangeable with the sought after 091 Bay ‘box. Shift rod points to the right from the side of the gearbox nosecone casting. Often confused with the 091 Bay ‘box because it also has ‘6 ribs’. Front of getabox sits significantly higher up in diesel models, requiring a diesel specific rear shift rod section
091/14 + R1984 – 19921913, 2109 Petrol, 1588, 1709 DieselThe ‘new’, long cased 4 speed positions the engine further back in the chassis. Shift rod points to the right, from the side of the centre gearbox casting, about 1/3 of the way along the ‘box. All new all gearshift components relative to earlier models. Also requires a diesel specific rear shift rod section
0945 + R1984 – 19921913, 2109 Petrol, 1588, 1709 DieselSame external dimensions as the 091/1, so also positions the engine in the further back location. Different front casing casting and mounting bracket. Revised gear lever mechanism to suit 5th gear. Some models have an incredibly low 1st gear, which is virtually redundant with even a little more torque than standard. ‘Dog leg’ shift pattern (i.e. 1st to the left and back). All previous version have the conventional ‘H’ pattern.
5 speeds don’t generally have any ‘overdrive’ – there is almost always a 4 speed with exactly the same ratios in top gear, as shown in the table below
094 SyncroG + 4 + R1985 – 19921913, 2109 Petrol, 1588, 1709 DieselThe Syncro gerabox is a special version of the 094 5 speed, with a front output for the 4WD. Also, in place of 1st gear, Syncro’s have the G gear Gelande (‘terrain’ in German), which is far lower than 1st. You never used in on the road (unless you’re stuck in a queue going very slowly), so Syncro’s are effectively 4 speed on the road. Unique front mounting arrangement and rear shift rod section.

If you are looking to identify the spec of a gearbox, the code as shown in the table below is always stamped into the gearbox (never cast in – all cast in numbers are part numbers for individual pieces). They are always followed by a series of numbers. These are a date code, so do not specify what spec the ‘box is.

The table below shows all the VW gear ratio we’ve been able to find. It covers almost all of the gearboxes used in rear engines bus models from 1968 onwards, but there are a few gaps in the info. All the data came from wherever we could find it, mostly back in around 2008. Where possible it came from workshop manuals, but much of it came from other far smaller tables online, so we don’t know it’s origin or how correct all of it is, but it’s probably the most comprehensive table out there unless someone else has genuine VW info.