How do you guys like your rear differentials? Our driving consists of mostly fast local roads/highways, and I'd rather avoid repeating the Corolla's 55 MPH @2000 RPM in 5th. What RPMs do the 3.07s run at highway speeds (hopefully, I can find this out myself sooner rather than later)? What do the 2.88s and 2.47s run? How is the 2.47 in the city? Is the 2.47 a direct bolt-on to my '84? Is there anything else I should consider? How does a potential 4-speed swap affect his?

Oh, and could I take a camper 5-speed w/extra-low first and mate it with the 2.47 to ease city driving?

__________________
"Senior Luna, your sense of humor is still loco... but we love it, anyway." -rickymay ____ "Your sense of humor is still loco... " -MBeige ____ "Señor Luna, your sense of humor is quite järjetön" -Delibes

1982 300SD -- 211k, Texas car, tranny issues ____ 1979 240D 4-speed 234k -- turbo and tuned IP, third world taxi hot rod

2 Samuel 12:13: "David said to Nathan, “I have sinned against the Lord.” And Nathan said to David, “The Lord also has put away your sin; you shall not die."

hi mate,

it depends which engine you do consider i.e I had some experience
with 300d n/a and turbo,manual or auto.... diff's act quite different under those two.

for the n/a manual I would not go under 2.88 as the starting will take forever
on the other hand turbo engine especially with auto will do nice with any
in range 2.24-3.07....only thing you have to decide what is the desired state
- low noise or top speed.

2.88 is my choice as you can see from the signature
2.24 is also from gasser and can be used also (quiet little thing
and a bit of a slow dog...2.47 will do fine IMHO)


edit; 2.47 w/o abs


380,500 1:2.47

380,500,560SEL 1:2.47 ABS

420SEL 1:2.47


as for the 4spd swap:

if you have 300n/a and a manual with 2.47 ...NO good. you have to go lower...3 point something...


.

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w126 500SEC gen II euro, powered by OM617 turbo stolen from 84 300SD 2.88 diff,EGR blinded
next wish/project: w114 coupe OM603 powered

also, most 2.xx diffs have the large flange that will need to be swapped for your vehicle's

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

I have a 2.88 diff I pulled from an '85 to put into my W126 with the 3.07.
I thought it was a direct bolt on. Are those flanges different?
Please tell me it ain't so!

Jeff

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1984 300SD 300,000 miles--two tank WVO setup
2.88 diff & 500SEL anti-squat rear end

He meant to say "2.47". The 2.88 came from the '85 diesels and it is a direct swap.

I have put the 2.88 in the SD ('84) and it is, for me, a perfect setup.

I would only recommend the 2.47 to those who do extensive high speed driving (70 mph +) on relatively flat roads and will suffer the difficulty in launching the vehicle from a standstill.

The 2.47 does have the larger case and requires a change of flange. It also may require a change in axle shafts but I am not certain.

I've got no complaints about my 2.47. I bought it that way so I can't really compare it to the stock diff. It turns over at about 2300rpm when cruising at 100km\hr so its nice and quiet on the highways. It is a little slow off the line if your on a really steep hill but I think that might be an issue with the bowden cable not engaging 1st as soon as it should. Theres a delay before it down shifts and there shouldn't be... Over all it seems good to me.

__________________
2004 F150 4.6L -My Daily
2007 Volvo XC70 -Wife's Daily
1998 Ford F150 -Rear ended
1989 J-spec 420SEL -passed onto its new keeper
1982 BMW 733i -fixed and traded for the 420SEL
2003 Volvo V70 5 Speed -scrapped
1997 E290 Turbo Diesel Wagon -traded for above
1992 BMW 525i -traded in
1990 Silver 300TE -hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold

I agree with Brian 100% on this.

My previous 617 had the 3.07:1 which seemed a bit high strung at 65-70mph on the freeway. The current SD has the 2.88:1 factory, seems about ideal considering the powerband of the motor and US speed limits. I suppose it could tolerate a 2.47:1 on the road, but with the A/C on and a locked fan clutch... I think it would be pretty sad around town.

These are econo cars, going 80mph is not going to permit good fuel econ regardless of which diff you have installed.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Yep.........80mph cost mucho fuel. I go 63 mph and the SD is currently getting a steady 29, even on the winter fuel.

I tend to run 85 on the toll roads around Austin... That will net you 19mpg in a wagon.

And that's with the 2.88

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'85 300TD "Puff The Magic Wagon" - Rolling Resto
'19 Mazda CX-9 Signature - Wife's sled
'21 Morgan 3-Wheeler P101 Edition
'95 E300d - SOLD
'84 300TD "Brown Betty" - Miss this one
'81 240D "China Baby" - Farm grocery getter

My 1978 300SD is driven 1,000 miles/week to and from work. With the 3.07:1 axle, 70 is 3000 rpm.

My 2.47:1 is almost ready to install, a 600 rpm reduction in cruise rpm...

__________________
Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

Dude! That's worth it.

__________________
"Senior Luna, your sense of humor is still loco... but we love it, anyway." -rickymay ____ "Your sense of humor is still loco... " -MBeige ____ "Señor Luna, your sense of humor is quite järjetön" -Delibes

1982 300SD -- 211k, Texas car, tranny issues ____ 1979 240D 4-speed 234k -- turbo and tuned IP, third world taxi hot rod

2 Samuel 12:13: "David said to Nathan, “I have sinned against the Lord.” And Nathan said to David, “The Lord also has put away your sin; you shall not die."

My car has the 2.88, From the graphs that I have seen the engine makes peak torque at about 2000 rpm. I don't accelerate hard and would be very happy with a 2.47.

I have looked at GM transmission adapter plates. The GM 4 speed auto has a .7 top gear. Might give similar effect if it would fit in the tunnel.

I am leaving my car stock unless a specific part quits.

__________________
85 Merc 300D - Unwinding 31 years of wear
86 VW TD
Mahindra Diesel
Iseki Diesel

In 2007 I didn't own a diesel.

The 2.47 actually doesn't make much difference in take off acceleration on a 300SD, it just holds each gear longer, and you don't need/use 4th under 50mph...highway acceleration in 4th does suffer a little, but the rpms are much lower and makes it very pleasant.

I have the torquemonster setup in my 300SD, a 1985 torque converter (2600 rpm stall speed) and trans + 3.07 diff. Front of the car practically lifts off the ground with takeoff torque. I dare say for the first 10-15mph it can take off faster than my 420....its great around the city, it just effortlessly takes off and gets up to 40-50 easily.

Overall the 2.88 is probably best for a diesel, and 2.47 or 2.24 for a gasser (of adequate power levels) The key with the diesels is the torque converter, it really makes a difference!

__________________
-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)

so what is the stock on a 84 sd?

am I imagining the w123 300 turbo D seems to have a taller or lower ratio rear end as it seems to rev slower.
cheers

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[QUOTE=SD300;3099623]so what is the stock on a 84 sd?

3.07

Jeff

__________________
1984 300SD 300,000 miles--two tank WVO setup
2.88 diff & 500SEL anti-squat rear end