Disabling LSD and use non-LSD oil

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Smart_Guy

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Hello guys!

In my MB W124, the LSD has been disabled by disconnecting the LSD ECU. Is it safe to use a non-LSD oil in the rear differential now that it's disabled? Does that make it act like a normal differential without needing an oil with LSD additives?

I'm using this oil by the way:
http://www.liqui-moly.de/liquimoly/produktdb.nsf/id/en_1413.html?OpenDocument&land=GB

I made a stupid mistake and jumped the gun using it.
 
So is this an LSD at all then? Are there clutch packs in the diff if its electrically actuated? Or is this selective brake distribution through a traction control type system.

If there are not clutches in there, it probably never mattered. If there were, the only difference is how they shudder, and Id suspect that they wont.
 
Ah, the diff is physically LSD. Dunno how it works. All I know is that there is a LSD ECU that I disconnected and no matter how much I try engaging it in tests, it does not work. The "working" light that indicates it being activated when needed does not show up. I also dunno if it has clutches (how does one know this anyway?).

Do the above details help?
 
I would at least siphon it out and add some M1 or Valvoline Synpower (cheapest options I know of that offer LSD add. packs)
 
It says non-LSD oil for non-LSD diff and LSD oil for LSD diff. But manuals always speak generally, not in details. So there is no definition for having LSD if it is actual LSD hardware or LSD actually active.

I don't want to run it normally anyway, I'm just wondering if I can at least use it for a couple of days to find the right oil and install it.
 
I would just grab some Lucas gear oil. It should be fine for use in both. It says on the bottle, it doesn't require LSD additive to be used with an LSD.
 
If it has a clutch pack, it will require an LSD (friction modified) gear oil, even if the lock-up is low.

When you say you disconnected the LSD ECU, what does that mean? If there's a controller, it probably controls hydraulic locking of the diff. If this is true, and your rear diff is a clutch-type, it will still lock up, just not fully and maybe not much at all, especially if the clutch pack is worn out.

How did you verify the LSD isn't working and why would you want to disable it?
 
Originally Posted By: Smart_Guy
Hello guys!

In my MB W124, the LSD has been disabled by disconnecting the LSD ECU. Is it safe to use a non-LSD oil in the rear differential now that it's disabled? Does that make it act like a normal differential without needing an oil with LSD additives?

I'm using this oil by the way:
http://www.liqui-moly.de/liquimoly/produktdb.nsf/id/en_1413.html?OpenDocument&land=GB

I made a stupid mistake and jumped the gun using it.


It's not quite ok to use non-LSD oil in your differential which physically has LSD clutch pack whose controls with LSD ECU is being disconnected by you.
It still acts like a LSD differential ... without a LSD ECU control , thus a LSD gear oil is appropriate.
blush.gif
 
Originally Posted By: gathermewool
If it has a clutch pack, it will require an LSD (friction modified) gear oil, even if the lock-up is low.

When you say you disconnected the LSD ECU, what does that mean? If there's a controller, it probably controls hydraulic locking of the diff. If this is true, and your rear diff is a clutch-type, it will still lock up, just not fully and maybe not much at all, especially if the clutch pack is worn out.

How did you verify the LSD isn't working and why would you want to disable it?


There is an Electronic Control Unit that has ASD printed on it (ASD is a type of LSD) that I disconnected. When ASD engages, a light in the instruments panel blinks in that period. That does not blink. I don't want to specifically disable it. I think it is already not working. The hydraulic pump is acting up so I drained all the fluid. I think this is why the LSD is not working in the first place. The issue is the current oil used that's not LSD modified. I want to make sure that it is okay to use it in this condition, at least for a couple more days until I find a solution if not.
 
Originally Posted By: zeng
Originally Posted By: Smart_Guy
Hello guys!

In my MB W124, the LSD has been disabled by disconnecting the LSD ECU. Is it safe to use a non-LSD oil in the rear differential now that it's disabled? Does that make it act like a normal differential without needing an oil with LSD additives?

I'm using this oil by the way:
http://www.liqui-moly.de/liquimoly/produktdb.nsf/id/en_1413.html?OpenDocument&land=GB

I made a stupid mistake and jumped the gun using it.


It's not quite ok to use non-LSD oil in your differential which physically has LSD clutch pack whose controls with LSD ECU is being disconnected by you.
It still acts like a LSD differential ... without a LSD ECU control , thus a LSD gear oil is appropriate.
blush.gif



Haha, I feel like a jerk now :p

Point taken. It's the language barrier. English is not my native language, sorry!

Oh boy, I put myself in deep. I guess I'll just find an LSD additive and add it... or not... Oh boy!
 
Originally Posted By: Smart_Guy
Does GM's additive work? I think it is the only we have here. The capacity is 1.1L. How much should I replace with LSD additive?

Yes, that's a fine product. As for the amount needed, that, I cannot answer, unfortunately.
 
Most NAPA and Autozone stores sell generic LS additives. I'm usually given Equa-torque. I suggest vacuuming out a small amount of gear oil, then add the LS additive.
 
With the drive axle off the ground, and the tranny in gear, or park, spin one wheel by hand.

If it spins easily and the other side spins the other way, you have no clutch pack action in the diff....if it's impossible to turn, you need LSD additives.
 
Cool man! I heard about this but doubted it. Thanks for confirming.

I'll try it in the morning.

I also found a Ford Friction Additive in the trunk this morning.

I remember now that I got it long time ago before replacing the diff. but didn't use it.

If it turns out to be an LSD diff., it will save me time to look for one.
 
Last edited:
Originally Posted By: Smart_Guy
Cool man! I heard about this but doubted it. Thanks for confirming.

I'll try it in the morning.

I also found a Ford Friction Additive in the trunk this morning.

I remember now that I got it long time ago before replacing the diff. but didn't use it.

If it turns out to be an LSD diff., it will save me time to look for one.


I personally think that the Ford XL-3 additive is better than (albeit MUCH stinkier than) the GM additive.
 
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