Comments on: R/C107 Differential Ratios

By: admin

admin — Sun, 21 Apr 2024 11:10:25 +0000

In reply to ionut boruga. Sorry I don't have a rebuild manual for a diff.

By: ionut boruga

ionut boruga — Sun, 21 Apr 2024 06:46:05 +0000

Hi there!
Do you have all technical data for rebuilding one?
Something genuine manual from MB.
I am planning to rebuild mine that has wasted clutch pads
but i don’t have any data regarding torque values, etc

Many tahnks

By: R. Botha

R. Botha — Fri, 15 Dec 2023 12:52:18 +0000

Hi there very interesting read. I stumbled on this chasing options to bring down the engine rpm on my W115 “74 240D, I recently done a engine swap to a 4M40 turbo engine the conversion was a lot of work but came out great and suit the car very well it is great to be able to keep up to traffic. The Mitsubishi max torque is at 2000 rpm though and with the standard gearing sitting on 3200 rpm at 100km/h and would love to bring that down looks like according to the work done here the ratios that will get me there will be the 2.65 or 2.72.
The cars that came with these ratios is just very very very scares in Australia. Is there any body with the knowledge to advise if I’d be able to change the crown wheel and pinion over in my diff if I can source them ??
Thanx Dutchie

By: admin

admin — Thu, 27 Jan 2022 23:35:23 +0000

I would go with 2.47 or even 2.82 off an early 500SE. I think 2.24 would be too tall for a 380

By: Richard Tyzack

Richard Tyzack — Thu, 27 Jan 2022 15:13:56 +0000

I have a UK supplied 1981 slc 380 with 4 speed gearbox and the diff ratio is way too high, I want to be cruising at 80 mph all day at below 3000 rpm so sounds like I need to find a 2.47, or should I go for the lowest at 2.24?

By: admin

admin — Sat, 14 Aug 2021 02:19:10 +0000

Yes, the lower the number the lower the revs on the highway.
its possible to replace the crown wheel and pinion but not a simple job. Not sure if the V8 one is the same size as the smaller one.

By: Tim Shapcott

Tim Shapcott — Fri, 13 Aug 2021 10:59:01 +0000

OK thanks for the advice

Not being a diff / gearbox expert the smaller the number the less the revs for a given speed….

I am based in the UK

Do I replace the whole diff or just the gears inside?

Tim

By: Tim Shapcott

Tim Shapcott — Fri, 13 Aug 2021 10:59:01 +0000

OK thanks for the advice

Not being a diff / gearbox expert the smaller the number the less the revs for a given speed….

I am based in the UK

Do I replace the whole diff or just the gears inside?

Tim

By: admin

admin — Fri, 13 Aug 2021 10:32:18 +0000

In reply to Tim Shapcott.

The V8’s used the bigger case, presumably for the torque. You would probably need the driveshafts etc.

Personally, I wouldn’t. The M103 doesn’t have the torque to drive a 2.47 ratio and certainly not a 2.24. I find even the 420 is a bit over geared and probably should have had a ratio like 2.82.

Not sure where you are located, but finding a 3.07 from a french market 300SE might be a better option?

By: Tim Shapcott

Tim Shapcott — Fri, 13 Aug 2021 10:23:54 +0000

Excellent post

Would it be possible to swop a 420 or 500 diff into a 300SL