Is this 500SL differential non-ASR?

[natejgreene9871]

400e rear diff non asr

I’m looking for a rear diff for my NON ASR 1993 400e.

Based on the photos, i think this one below is from a NON ASR 500sl.

Can anyone confirm this is what I need? I don’t see the two sensors on the top, only the single one on the side.

https://www.ebay.com/itm/266692028547

 

[gsxr]

Yep, that should be plug+play in your non-ASR 400E. Replace the side radial seals and re-seal the rear cover with Right Stuff or similar before installing. I'd leave the pinion seal alone unless it starts leaking, those rarely leak.

You'll need a speedometer correction module, I use the YellowBox.

 

[winmutt]

Wanna buy mine?

 

[natejgreene9871]

Yep, that should be plug+play in your non-ASR 400E. Replace the side radial seals and re-seal the rear cover with Right Stuff or similar before installing. I'd leave the pinion seal alone unless it starts leaking, those rarely leak.

You'll need a speedometer correction module, I use the YellowBox.

Perfect, I have a yellow box on hand. Ordered it last year. Thanks all for the input

 

[winmutt]

Perfect, I have a yellow box on hand. Ordered it last year. Thanks all for the input

Ah you were looking for a 2.65?

 

[natejgreene9871]

Ah you were looking for a 2.65?

Yes, I was torn between the 2.65 and the 2.82.

Ended up ordering 2.65, hopefully it will feel fast enough…

 

[winmutt]

I have a 2.65 in mine, the 2.82 would lack significant traction in most conditions.

 

[gsxr]

I have a 2.65 in mine, the 2.82 would lack significant traction in most conditions.

...which is why LSD helps, dramatically, if you don't have ASR. The "one wheel peel" gets annoying. I don't know why MB didn't have LSD as standard equipment on all 124's except perhaps the carbureted 4-cylinders (never sold in USA).

ASR is sort of electronic limited-slip, and it works very well under most (not all) conditions.

 

[natejgreene9871]

...which is why LSD helps, dramatically, if you don't have ASR. The "one wheel peel" gets annoying. I don't know why MB didn't have LSD as standard equipment on all 124's except perhaps the carbureted 4-cylinders (never sold in USA).

ASR is sort of electronic limited-slip, and it works very well under most (not all) conditions.

Are you saying this r129 differential I ordered has LSD? And my stock 400e diff is NON LSD?

Or just that it would be nice to have on a non asr 2.82

 

[gsxr]

Are you saying this r129 differential I ordered has LSD? And my stock 400e diff is NON LSD?

Nope. All 124 chassis have open differentials, NO LSD... the only exception being 4Matics and models with optional ASD.

Both your new R129 diff and original 400E diff are standard, open differentials.

Or just that it would be nice to have on a non asr 2.82

It would be nice to have both ASR and LSD, but LSD is better than nothing.

 

[natejgreene9871]

Ok so I have been messing around with my yellow box. I think I have this thing set correctly?

Do I set the box using the difference in ratios? For example 2.65 (new gears) - 2.24 (old gears) = .41


OR just set the box to the new 2.65 ratio? The closest ratio listed on the chart is 2.6610. That is how I currently have it set.

Anybody remember?

 

[gsxr]

It's not that simple. The ratio is a percentage difference in speed indicated.

You'll need to do more maths, and likely also need some trial & error adjustments.

I like to verify GPS readings at 25, 50, and 75mph so I know if the final reading is off by 1-2mph more at lower or higher speeds... it's rarely dead-accurate through the entire range. Non-stock wheel/tire sizes will affect the readings as well, which is part of the reason for the trial & error.

 

[AMG5PT4]

@gsxr - keeping my comment slightly on-topic, I have installed Dakota Digital boxes (similar to the Yellow Box) in my W126 because I changed the rear diff from stock 2.24 to 2.82 (LSD, ABS). For the install, there is a ground wire with each, and I am sure for the Yellow Box. I attached the ground wire to one of the 3 large ground wire bolts on the steering column and then spliced in the signal wire to the appropriate wire to the speedo connector. Calibrated the DD box using a speed gps app. No issues.

However, in both instances (the older DD I bought 12 years ago or so and the new DD box I bought last year), I get significant electronic interference to my left multi gauge (Fuel, oil pressure, water temp) - the gauge goes haywire (pun intended). Jono suggested I run a temporary wire straight from the battery - terminal to the DD box to see if that helps. Have you ever had electronic interference with your install?

 

[gsxr]

However, in both instances (the older DD I bought 12 years ago or so and the new DD box I bought last year), I get significant electronic interference to my left multi gauge (Fuel, oil pressure, water temp) - the gauge goes haywire (pun intended). Jono suggested I run a temporary wire straight from the battery - terminal to the DD box to see if that helps. Have you ever had electronic interference with your install?

Oh weird! I had the YellowBox on 2 different cars, located directly behind the clock/tach. I tapped into available +12v switched power from one of the cluster connections (forget which). Zero interference issues with any of the gauges. Wouldn't hurt to try running an additional ground wire, and/or a direct-to-battery wire if the DD can be powered continuously.

 

[AMG5PT4]

the new DD has to have switched power to operate while the original one could use direct power at all times. Jono and I will run a ground directly from the battery through the window to see if that has any impact. I also just sent an email to DD tech support. Just so odd.

 

[natejgreene9871]

Does anybody know what wire/pin on the back of the cluster is the speed reading (receives output from yellr box)

 

[gsxr]

 

[natejgreene9871]

View attachment 208324

Wow you are quick, thank you. Looks like I need to snip and tie into the white wire I circled

 

[gsxr]

Yup! You'll splice the YellowBox in between after cutting that wire.

 

[gerryvz]

I never had a problem with my ratio box since 2006 or so when I did a 3.07 in my 560SEC's 2.47. It's still working just fine going on 23 years. It's tucked back behind the instrument cluster. It's not a YellowBox or Dakota Digital though -- I have the instruction manual for it in my files, so I'll get the brand. I checked a couple of years ago and they were still selling it.

As I remember, for calibration, I had to take the car out on the road and I used mile markers on the freeway to calibrate it, then did the maths and programed the correct ratio in with the DIP switches. Over the years I've casually checked the speed via mile markers, phone GPS and radar in construction zones and residential areas, and it's never read more than 1 MPH "off" of the external readings.

 

[gerryvz]

Does anybody know what wire/pin on the back of the cluster is the speed reading (receives output from yellr box)

View attachment 208322View attachment 208323

You need to splice into the power wire in the bundle that plugs into that round plug on the back of the cluster there. I can't remember which wire it is.

 

[gerryvz]

I never had a problem with my ratio box since 2006 or so when I did a 3.07 in my 560SEC's 2.47. It's still working just fine going on 23 years. It's tucked back behind the instrument cluster. It's not a YellowBox or Dakota Digital though -- I have the instruction manual for it in my files, so I'll get the brand. I checked a couple of years ago and they were still selling it.

As I remember, for calibration, I had to take the car out on the road and I used mile markers on the freeway to calibrate it, then did the maths and programed the correct ratio in with the DIP switches. Over the years I've casually checked the speed via mile markers, phone GPS and radar in construction zones and residential areas, and it's never read more than 1 MPH "off" of the external readings.

Here are a few photos of the instruction book from my ratio box. They are still selling it -- $180 on their web site.



Here are a couple of links relating to this ERA box from Abbott:

Abbott Enterprises - ERA

Cable X and ERA(Electronic Ratio Adapter)

Abbott Enterprises, Inc. manufactures and repairs various speed devices for trucks, trailers, buses and the automotive industry.

www.atrol.com

ERA (Electronic Ratio Adapter) Your Speedometer Solution

Abbott Enterprises, Inc. manufactures and repairs various speed devices for trucks, trailers, buses and the automotive industry.

www.atrol.com

Wiring diagram is below. Note that it only requires a switched power lead.




I have never (in 19 years) had any electronic interference with a switched power lead.

 

[natejgreene9871]

Here are a few photos of the instruction book from my ratio box. They are still selling it -- $180 on their web site.
View attachment 208466 View attachment 208467 View attachment 208468 View attachment 208469


Here are a couple of links relating to this ERA box from Abbott:

Abbott Enterprises - ERA

Cable X and ERA(Electronic Ratio Adapter)

Abbott Enterprises, Inc. manufactures and repairs various speed devices for trucks, trailers, buses and the automotive industry.

www.atrol.com

ERA (Electronic Ratio Adapter) Your Speedometer Solution

Abbott Enterprises, Inc. manufactures and repairs various speed devices for trucks, trailers, buses and the automotive industry.

www.atrol.com

Wiring diagram is below. Note that it only requires a switched power lead.
View attachment 208470



I have never (in 19 years) had any electronic interference with a switched power lead.

Good info thanks for sharing

 

[natejgreene9871]

Out here in the driveway trying to Google wiring diagrams for the cluster. I have everything hooked up to the yellr box except switched 12v power. Does anybody know what wire to tap into?

 

[natejgreene9871]

Never mind. Everything you need is right here in this plug. Black/violet/red stripe is switched power. White wire is speed sensor.

 

[natejgreene9871]

So everything here was a success. Got the differential resealed, installed. Yellr box is working well. I got the speedometer correction ratio by taking an average across five speed readings. It seems dead accurate, just tested on the highway and around town compared to my phone.

this was more work than I expected. I didn’t anticipate having to remove the exhaust to get to the drive shaft center support. Took several hours of work.

Overall I am definitely happy. The 2.65 feels right. It is enough power that you can break the wheels loose if you want, but not too much to require asr. I can’t imagine why the USA 400e didn’t leave the factory this way, It’s just better all around and it clearly feels like the “correct” ratio the car was designed to have.

If I had to do it again I would more strongly consider going to the 2.82 but the availability of the 2.65 r129 diffs make it easier to source.

Thanks all for the input.

 

[natejgreene9871]

Also these worked good I recommend them

 

[gsxr]

I can’t imagine why the USA 400e didn’t leave the factory this way, It’s just better all around and it clearly feels like the “correct” ratio the car was designed to have.

2.65 was the original design! Only North America and Japan received the silly 2.24 gearing. For USA/Canada it was allegedly to avoid a gas-guzzler import tax. Probably something similar for Japan. Every other region got the standard 2.65 gears.

If I had to do it again I would more strongly consider going to the 2.82 but the availability of the 2.65 r129 diffs make it easier to source.

The 2.65 option is by far the easiest. The 2.82 options require more part swapping (since it's almost impossible to find a good used 036 diff).