300SD dif??????

[The Gears]

Can anyone tell me what the dif ratio is in a 1894 30SD
I am planning to buy one tomorrow. My 84 300D had a 3.07
Is the SD the same.
Hope to get an answer to night.
Thanks

[pawoSD]

Yes it is the same. The 1985s have a 2.88 ratio, all prior years have a 3.07.

[The Gears]

Thanks pawdSD
Not really looking forward to doing the change again. Are there any good
2.88 difs around any more?

[Actros617]

Get a 2.47 they are even better and easier to find

[charmalu]

Originally Posted by The Gears

Can anyone tell me what the dif ratio is in a 1894 30SD
I am planning to buy one tomorrow. My 84 300D had a 3.07
Is the SD the same.
Hope to get an answer to night.
Thanks

Not too many 1894 30SD left , may have been one or two HP

Did you mean 1984 300SD? they are a 3:07 also.

The 85 300D and 300SD have the 2:88.

The Gasser V8 have the 2:47. I pulled one out of a 85 380SE.
The 86 to 91 W126 will not fit the W123, the mounting is different.

Charlie

[The Gears]

Thanks Charlie. Will the 2:47 leave the car under powered in a high wind or a highway hill?
Love to have that ratio if it will work. Has that match been made by any one as yet?

[pawoSD]

Originally Posted by The Gears

Thanks Charlie. Will the 2:47 leave the car under powered in a high wind or a highway hill?
Love to have that ratio if it will work. Has that match been made by any one as yet?

Depends on the engine.....we swapped a 2.47 into my dad's SD and it works well, a bit slower at highway speeds than with a 3.07, but much lower RPMS and quieter. It can still easily hold 80-85 even on a hill.

[charmalu]

Changing from a 3:07 to a 2:88 or a 2:47 will throw off the speedometer.
Be sure to get the speedometer from the donor vehicle. the spedo is geared to the diff.

It would look cool to have a 2:47 with the 160mph spedo in a SD.

I think the flange on the 2:47 diff will have to be swaped from the one off the SD
The gassers use a larger flange.

If you go this route, then you will have to determine the friction preload on the pinion seal and bearing.

www.peachparts.com/shopforum/showthread.php?t=233540

Charlie

[The Gears]

Thanks charlie. I have learned a lot on this subject in this thread.
I will swap the 2.88. I did the 2.88 swap to my 84 300D and I like very much the way it feels in town and on the highway.
Should I re seal the unit or assume that the seals are good if the case is dry?

[sknaffl]

On this same subject...but different model....

Does anybody know which diff's are interchangeable with the 116? I have an 1980 300SD.... I love everything about the car but it really winds out at highway speeds. I have a friend who has an '85 SD that cruises at a much lower RPM. Would a swap from a 126 work into a 116?

Thanks