Getrag 5-speed dogleg gearbox for BMW and Mercedes

Getrag built a sports transmission for BMW and Mercedes from 1979 to 1993 with first gear on the left rear. It has now achieved cult status. There was also a version for Jaguar and Opel.

First gear, rear left: The unusual shift pattern is a feature of the Getrag Sport transmission for BMW and Mercedes. However, there was also a longer "overdrive" variant with a conventional shift pattern, which Opel and Jaguar also used. The sports variant with a directly translated fifth gear and the first gear on the left in the rear are used by BMW and Mercedes in various models. The supplier manufactured the gearbox from 1979 to 1993. The name "dogleg" (English for dog leg) gave the gearbox the image that the shift lever gave when first gear (rear left) was engaged: with a little imagination you can see it Bellows around the lever and its shift stick with knob protruding to the rear, like a dog stretching out a leg backwards or – somewhat cruder – lifting it. The British also refer to sharp curves or golf courses with a fairway that bends to the left or right as a "dogleg".

What were the goals during development?

Of course, the scheme that deviates from the usual H with first gear at the front left was not devised: Rather, Getrag wanted to build a light, compact and smooth-running transmission with a high level of efficiency: "In order to keep the center distance as small as possible with high power density (small installation space, low weight and yet high rigidity), a triple bearing of the transmission output shaft and the auxiliary shaft was developed," explains the manufacturer. All wheels and shafts have roller bearings, which ensures high efficiency. An aluminum housing keeps the weight down. The wheelbase is 76 millimeters.

The gearbox is designed for a torque of 380 Newton meters. It is therefore also suitable for larger six-cylinder engines, such as those used by BMW, Jaguar, Mercedes and Opel at the time. The sports variants have first gear on the left rear - this shift pattern was found in the 190E 16-valve engine and in the 300 CE-24, for example. Another feature of the sports variant is the directly translated 5th gear and the very short translated first gear.

How many gearboxes of this type has Getrag built?

The two biggest buyers were BMW and Mercedes. Getrag delivered 130,000 overdrive 265s for the 5, 6 and 7 series with the M30 six-cylinder and 22,000 sport 265s to Munich and Dingolfing. BMW installed the gearbox in the 5-series E12 and E28, the 6-series E24, the 7-series (E23) and the E30-M3. 140,000 Getrag 275s in sports and overdrive versions went to Mercedes. There, Mercedes used them in the W 201, W 124 and R 129 series in combination with four-valve engines. Specifically, these were the 190E 2.3-16 and 2.5-16 models as well as the Evo 1 and Evo 2, the 124 series and the SL (R 129) with the M 104 straight-six (300-24 and 320) Getrag built 12 for Jaguar.000 and for Opel 28,000 five-speed 265, each in an overdrive version.

Getrag 265 for BMW, Opel, Jaguar

Like BMW, Jaguar and Opel use the 265 transmission type, but with a loose sliding flange on the output. The Getrag 265 for BMW had a fixed output flange. According to the manufacturer, the gearbox housing was "designed for BMW in such a way that it could be equipped with different clutch bells and thus attached to different engine flange patterns."

Getrag 275 for Mercedes

The Getrag 275 for Mercedes has an integrated clutch bell and shift units on the side. This is different with the transmissions for BMW, Jaguar and Opel: Here the clutch bell is separate and the transmission housing has a central selector shaft.

What is the advantage of first gear on the left rear?

With the different shift pattern, gears 2 and 3, as well as 4 and 5, which are frequently used when driving, were in a longitudinal aisle, so that changing between them only required a simple forward or backward movement. The path from second to third gear is short. This is great for narrow and winding country roads: Before corners, you can quickly downshift without changing lanes and then quickly upshift again.

No wonder, according to Getrag, a racing version of the gearbox was installed in almost all vehicles with rear-wheel drive and front-engine in the DTM of the 80s and 90s. Of course, the wheel sets were adapted for racing and the spread was narrower. If you want, you can still think briefly of Roberto Ravaglia or Johnny Cecotto on your home track - and the doorknob duels of the German Touring Car Championship at that time.

Shifting scheme from motorsport

Motorsport is also the reason for the shifting scheme: On racetracks, first gear is only needed to start off. It is much more important to be able to change quickly and without changing lanes between second and third gear or between fourth and fifth. A feature that was no longer necessary when sequential and automated transmissions became established in motorsport.

How does the "dogleg" gearbox drive?

In today's real road traffic, a Mercedes 320 CE with the Getrag 5-speed can remain in the highest gear because of the directly translated fifth gear on motorways from construction sites up to the top speed. The M-104 straight-six pulls up smoothly, linearly and with a nice sound at just over 1,000 rpm. The transmission switches between second and fifth gear without hesitation and over short distances. In any case, the first is only necessary for starting from a standing start – like back then on the race track.

The extremely short gear ratio of the first makes starting off in conjunction with a high-torque six-cylinder, such as in the 320 CE, an exercise in concentration.With the short gear ratio and the high-torque engine, the play in the drive train is quickly felt; if you switch gears improperly, you set the whole system in motion.

So that it doesn't jerk when changing to second and the whole, nice propulsion doesn't collapse, smooth shifting is the order of the day - and a smart choice of speed: Between 2,200 and 2,500 rpm is best. Compared to the manual transmissions in other Mercedes models of the time, the distances between the gears are shorter and more defined, but the effort required to shift gears is slightly higher. However, a real comparison is not easy with transmissions that have been in use for around 30 years: maintenance and treatment can also affect shiftability here.

Compared to newer manual transmissions, the "dogleg" scheme and shiftability seem a bit antiquated. The translation with a very short first and direct fifth gear is more of an anachronism - and not necessary with a powerful six-cylinder. In the case of a Mercedes 320 W 124, the speeds on the Autobahn correspond to those of the four-speed automatic transmission; at top speed the engine turns off. An active driving design that was rather unusual at Mercedes at the time and today ensures that some road users do not expect the speed of this 124 model at all. In any case, the term "sports transmission" is not wrong.

Conclusion

Fans are right to celebrate the "dogleg" transmission: The Getrag 265 and 275 with first gear at the rear left is a sophisticated transmission for connoisseurs. The rare shift pattern is a bit of a challenge. After a short period of getting used to it and with a little concentration, the gear can be operated very easily from the wrist. The short distances between second and third as well as fourth and fifth gear never cease to amaze when driving.

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