Hi guys, im getting started on the SEC -> diesel project again, and I have had one problem nagging at me for a while, the stock diff is a LSD 2.47, Since most of my driving is done at 65 MPH, I would prefer a decent rear gear.

So Im curious as to how I might swap my 2.47 LSD for a 3.07 from an 83 300 SD. Can I keep the LSD or not.

I dont think my clutch will be happy if i leave the 2.47 in there.

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1984 Euro 300SDC, (4spd standard)
1986 Toyota Landcruiser Diesel HJ60 5spd X2

Gone but not forgotten (some sold, some stripped)
1983 300 SD, 1985 300 SD, 1983 240D, 1986 300 SDL, 1985 300 SDL, 1983 300 D, 1984 300 D, 1985 300SD, 1987 300 SDL, 1983 300 SD, 1985 300 TD Euro, 1983 380SEC, 1990 300 D, 1987 300D, 1982 300D, 1982 300D, 1994 E420, 1987 300 TD, 1987 300 D, 1984 300 D

It would be geared pretty high, but I think that unless you abuse it, the clutch would handle the slight extra load at start up. You might not like the performance, but you could make more use of 3rd gear in city driving. You might wind up with a mileage maker extreme, which with a buck a liter or more for fuel isn't all bad.

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Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!

It has been proven that using a 2.47 in the 617 powered cars does little to improve mileage, it just lowers rpms/noise/acceleration. With a manual I bet it'd not be much fun, especially on hills!

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

I would recommend no higher than the 307. YOur clutch will be happier if you go with the 346 ratio that came on the 300d na euro sticks and na 300d automatics that were brought here.

Tom W

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Actually I would really debate that 2.47 doesnt make a big difference, it certainly does, I put a 617.951 into a 500SEL and averaged 27.5 MPG over 60Kmiles, at times hitting 32 MPG,

DO i need a diff from a W126 or are the ratios from a W123 fair game. Can i keep my W126 LSD or does that need to go when i change the ratios.

__________________
1984 Euro 300SDC, (4spd standard)
1986 Toyota Landcruiser Diesel HJ60 5spd X2

Gone but not forgotten (some sold, some stripped)
1983 300 SD, 1985 300 SD, 1983 240D, 1986 300 SDL, 1985 300 SDL, 1983 300 D, 1984 300 D, 1985 300SD, 1987 300 SDL, 1983 300 SD, 1985 300 TD Euro, 1983 380SEC, 1990 300 D, 1987 300D, 1982 300D, 1982 300D, 1994 E420, 1987 300 TD, 1987 300 D, 1984 300 D

You can use a W123 diffs but the LSD goes when you remove the 2.47 and you have to change the axle spacers.