rear axle question

[dreyer635]

Hi
Perhaps a dumb question, but how can I find out the ratio on my rear axle? (280Sl 4 speed US model built 25 nov 1968) (I can't testdrive it at the moment)

My datacard does not show any codes in the 200 range i.e. 232 for a 4,08:1 or 212 for a 3,93:1 - or is it me that don't know were to look?

At the moment I have the rear axle out of the car, and inspection after stamped numbers is easy; but I cant find any number refering to the ratio. Is there anyplace on the axle the ratio is spamped? Where?
I have found numbers (difficult to read)but I beleve  296682 and 110357 is spamped on the right swing axle part (not on the diff)

Anybody out there that knows?

Regards
Kjell
Norway

280 SL 4 speed

[DaveB]

If it's like mine it will be stamped on the lower left of the central casing (looking from the rear).

DaveB

[Naj ✝︎]

Kjell,
Look on the left side of the diff housing. There is a horizontal rib with the face machined off and the the ratio and serial # is stamped on it.

naj

65 230SL
68 280SL

[ja17]

Hello Kjell,

Late version W113 cars had the number on the side rib as Naj has mentioned. Earlier versions had the ratio on the rear of the casting as described by Dave. I am not sure when the change occured. Here are some photos of both.

Download Attachment: gear ratio location early.JPG
51.67 KB

Download Attachment: gear ratio location late.JPG
40.28 KB

Joe Alexander
Blacklick, Ohio

[TheEngineer]

Look at the speedometer and the tachometer: With a 4.08 rear axle ratio the tachometer needle and the speedometer needle will always be parallel in fourth (high) gear. i.e. at 2000RPM it will indicate 32 MPH. The 4 speed came with the 3.92 rear axle. The speedo should show 3300 RPM at 62 MPH. You don't need to drive the car, one look at the speedometer dial will tell.

[dreyer635]

Thanks - found it. I've got a 4.08. As always - it's easy when you know!
Regards
Kjell

[TheEngineer]

Many years ago, when cars were very rare and roads were not paved, this old guy from Germany took his Mercedes east into Poland. These cars were not as reliable then, as they are now, when it rarely happens that a car just quits. But that is what happened to the old guy. Fortunately, there was a blacksmith nearby who claimed to know something about cars. He looked at the car, opened the hood, got a small hammer and tapped the engine once. He started the car and it ran flawless. The old guy was overjoyed and asked to pay him. The blacksmith wanted twenty Kopeks. That was a lot of money then. The old guy was shocked and asked the blacksmith to please itemize his charges. The blacksmith did: One tap with small hammer: One Kopek. Knowing where to tap: 19 Kopeks.

'69 280SL,Signal Red,113044-12-007537,tired engineer, West-Seattle,WA