My 280ce has a 3.46 ratio. I could put in a 2.88.

Is this a good idea? It would be nice to have a longer first gear, and I never mind having low cruising revs.

But is this too much of a jump?

Manual box or auto box?

If an auto box with 1st gear start, 2.88 should be fine on Long Island, beware the Catskills. If a manual box, 2.88 may be a bit tall.

Yes, its a manual 5 speed box. 1st is pretty short at the moment ...

I always go with taller rear tires,for extra mpgs

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1999 w140, quit voting to old, and to old to fight, a god damned veteran, deutschland deutschland uber alles uber alles in der welt

The 5-speed boxes that attach to a M110 have 1st ratios of ~3.9:1, and a 5th of ~.8:1.
2.88 x .8 = 2.3; that is a very tall top gear to try to pull with a 2.8L engine.
2.24 was used with the 560 V8s, but not in the USA.
A 3.07:1 final may be worth a try.

Guys - I think we are getting old. How many of the youngsters now even know what "tall" means? In reference to gears, I mean.

like my 2256016s were 26.1 diameter 2356017s are 29 almost

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1999 w140, quit voting to old, and to old to fight, a god damned veteran, deutschland deutschland uber alles uber alles in der welt

Ok . So it's a no to 3.46 but a yes to s 3.07?

It may be worth noting that 3.46 x .8 (5th) = 2.77
That is taller than the 2.88 (4th 1:1) that was used with some 3L diesels.

Yes, 1st with the 3.46 is short (3.9 x 3.46 = 13.49), however, as we can see, without changing the gearbox internal ratios, making 1st taller also shifts 5th upward too far. A 3.07 x 3.9 = 11.97, and 3.07 x .8 = 2.46

The gearing as delivered in Europe (3.46) w/5-speed is just fine for a cruise south thru Bavaria, and then a week spent crawling around in the Austrian/Swiss Alps!

Heavy car with a small engine... leave it as is. That engine was designed for relatively high revs, but should be doing no more than about 2500 at 60 MPH with the five-speed. A taller gear that drops it to 2000 or less will make fifth mostly useless.

My 190E 2.6 special order five-speed has a 3.27 axle, a 3.86 first and 0.80 fifth. It runs about 2200 at 60 in fifth and it's useable down to 30-35 MPH after I figured out how to make the spark advance more aggressive. Prior to that the increase in advance with engine speed was so lazy that fifth wasn't useable below about 45 MPH.

First-second and to a lesser extent, second-third have a wide spread and revs tend to hang, which means it has to be shifted fairly slow to be smooth, but 3-4 and 4-5 are progressively closer, and I can shift faster. Other than the revs hanging the gearing is good and the short first gear means minimal clutch slippage for long life.

The other problem you may have is finding someone who can properly set up a new ring and pinion... best to buy a different geared axle that will fit, but for the time an expense, I don't think you'll gain much.

A few years ago there was a 300SE owner who wanted a taller rear axle. He replaced the 3.46 with a 2.87, but it wouldn't pull fourth gear (4-speed auto, 1:1 fourth) even on a slight highway grade or good headwind. I don't think he gained much.

The reason the 300 SE has such a short rear gear relative to the V-8 S-class models is that it was something like 4000+ pounds with a torque-shy 3L engine, so it needs a short axle ratio to have decent performance, and that applies to your 280SE, too.

It turns fairly high revs at 60, but Mercedes inline sixes are butter smooth, and the M103s don't achieve peak torque until the mid-4000 range, so they need to rev.

I run into the same issue with vintage Corvette owners, especially if they own a modern Corvette. They're accustomed to less than 2000 revs at maximum freeway speeds, but their torque shy, high revving Special High Performance/Fuel Injection 327s with a close ratio four-speed (2.20:1 first) and a 4.11 axle are turning 3000 at 60. They could install a 3.08 (2350 at 60), but then it will be like a five speed with no first gear (close to 80 MPH at 6500 in first), so it will be a dog around town and eat clutches.

I tell them the same thing. The engine was designed to rev (again, mid-4000 rev torque peak, 6000 peak power, 6500 redline), so let it rev.

Duke