Too much LSD additive?

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What negative effects would occur if you put too much LSD additive in your diff? I was thinking of adding more to avoid chattering in the future, but do not want to ruin my Limited Slip or anything else. So would adding more help in any way? Is there too much and if so would that be say double the amount or more than the? Thanks
 
The additive changes how the clutches grab. Most likley there will be no problems with the amount added. You can get real hard core and use a non posi lube and add a little at the time to get the locking you want,an old hot rodding trick.
 
Too much, and it will pretty much act like an open diff, as the clutches will slip too easily. Either go with what the manufacturer recommends, or as little as you can get away with without chattering.

In the case of the rear LSD in my Jeep, I'm running Mobil 1 75W-140 LS gear lube, and the FM already in it is enough to keep it from chattering, so I didn't add any more.
 
Originally Posted By: Steve S
You can get real hard core and use a non posi lube and add a little at the time to get the locking you want,an old hot rodding trick.


Yes, it is.

BUT, Eaton tech themselves will tell you that you will burn up their clutch packs pronto running too little in anything but a direct straight line/drag racing (i.e.; street driving, road course/autocross use, etc.).
 
I'm no fan of clutch type LSD's, many of them have had issues in my higher powered street cars and dedicated drag racers. But most of them are fairly reliable in stock cars and trucks.

Brand new Getrag units are experiencing the same failures/issues on brand new LC/LX Chrysler cars. Simply not enough clutching capacity for the torque.
 
I put about between 5-6oz. in my rear diff, and it is still turning both tires if I "peel out". I use that method to check the grab as if the clutches do get weak it will turn only one wheel. So far it has been fine I will keep an eye on it, and any other information would be greaty appreciated. Many thanks for the quick replaies so far. and the video posted was awesome, too much LDS.. HEHE.
 
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Originally Posted By: SteveSRT8
I'm no fan of clutch type LSD's, many of them have had issues in my higher powered street cars and dedicated drag racers. But most of them are fairly reliable in stock cars and trucks.

Brand new Getrag units are experiencing the same failures/issues on brand new LC/LX Chrysler cars. Simply not enough clutching capacity for the torque.


Even though I never had any problems with my Eaton c.f. clutchpack Posi myself, I tend to agree with you on this.

BUT, the problem with the Eaton/Detroit True Tracs, and most other helical/worm gear/Torsen type diffs (save for the new Auto Tech Wave Trac, Torsen T2R, and some of the pure racing 'Gold/Platinum' Tracs) is that there is not quite enough biasing/bias ratio for great road course handling/turn exit powering, etc.
frown.gif
 
Agreed.

Many of my GM products have had a delay in the Locker rear that is not conducive to high performance driving.

I'd be timid about cutting back on the additives in fear of long term issues.
 
I was told by a former Dana drivetrain engineer that too much LSD additive effects the viscosity and decreases oxidative resistance of the oil, that is resistance to oxidation from heat. Too little, of course, causes chattering which in turn wears the unit out prematurely or breaks it outright. He suggested that the best procedure is to use as little as it takes to eliminate chatter and no more, but you have to experiment to find that point. Each oil has slightly different friction characteristics so each may need more or less additive.

That process involves extra effort, which is why not too many people do it. It's outlined in some manuals, though it's more common to see, "Add X-oz." The one time I did it the hard way, it took me the better part of an hour. Starting with a newly installed plate-clutch type LS. I filled the axle to about 90 percent and located a parking lot near my home. With no additive I went to the parking lot and did some tight figure 8's in both directions, with a little power on. Chattered like a big dog. I added about half a bottle of the Ford additive and did some more figure 8's. At first it chattered just as bad, but you have to work the stuff into the unit and mix it well with the oil. After a little while, the chattering lessened considerably. I added about a quarter of a bottle more and that eliminated the chattering. For then. Later, it started to chatter a little so I added the rest of the bottle and it chattered no more. The instructions with the unit said to use two bottles, but I don't recollect their capacity in ounces, so I used half that.

I have a new cone clutch style LS now and since it was installed by the mfr., they installed their recommended amount of additive (two bottles). No chattering at all (cone clutches are somewhat less prone to chattering but they still do). When I change out that oil, I should probably have it analyzed to see if it's sheared a bunch and oxidized a lot. If I remember to do it.
 
Originally Posted By: Jim Allen
I was told by a former Dana drivetrain engineer that too much LSD additive effects the viscosity and decreases oxidative resistance of the oil, that is resistance to oxidation from heat. Too little, of course, causes chattering which in turn wears the unit out prematurely or breaks it outright. He suggested that the best procedure is to use as little as it takes to eliminate chatter and no more, but you have to experiment to find that point. Each oil has slightly different friction characteristics so each may need more or less additive.

That process involves extra effort, which is why not too many people do it. It's outlined in some manuals, though it's more common to see, "Add X-oz." The one time I did it the hard way, it took me the better part of an hour. Starting with a newly installed plate-clutch type LS. I filled the axle to about 90 percent and located a parking lot near my home. With no additive I went to the parking lot and did some tight figure 8's in both directions, with a little power on. Chattered like a big dog. I added about half a bottle of the Ford additive and did some more figure 8's. At first it chattered just as bad, but you have to work the stuff into the unit and mix it well with the oil. After a little while, the chattering lessened considerably. I added about a quarter of a bottle more and that eliminated the chattering. For then. Later, it started to chatter a little so I added the rest of the bottle and it chattered no more. The instructions with the unit said to use two bottles, but I don't recollect their capacity in ounces, so I used half that.

I have a new cone clutch style LS now and since it was installed by the mfr., they installed their recommended amount of additive (two bottles). No chattering at all (cone clutches are somewhat less prone to chattering but they still do). When I change out that oil, I should probably have it analyzed to see if it's sheared a bunch and oxidized a lot. If I remember to do it.



Great repsonse, Thanks!
 
Originally Posted By: Wolfpack
What negative effects would occur if you put too much LSD additive in your diff? I was thinking of adding more to avoid chattering in the future, but do not want to ruin my Limited Slip or anything else. So would adding more help in any way? Is there too much and if so would that be say double the amount or more than the? Thanks


LSD additives tend to not be good for oxidation stability.
 
Originally Posted By: Whitewolf
Originally Posted By: Wolfpack
What negative effects would occur if you put too much LSD additive in your diff? I was thinking of adding more to avoid chattering in the future, but do not want to ruin my Limited Slip or anything else. So would adding more help in any way? Is there too much and if so would that be say double the amount or more than the? Thanks


LSD additives tend to not be good for oxidation stability.
Which would make it wear more or deteriorate faster?? I am not sure if thats really bad or just a bad thing help a rookie out?
 
That means that too much of it reduces the oil's oxidation stability, so it will break down and oxidize faster. In other words, too much LSD additive can shorten the working life of the oil.
 
If you change your gear oil every 30k/2-3yrs, then you don't have to worry about it.
 
Ahh, Thanks that makes great sense now. I will change mine on a regular shcedule so I am not too worried, and the LSD is locking upi really well with no chatter, so I'm good, I think. Thanks for the responses Fellas!
 
One thing to bearin in mind is that oxidation is heat related, so you would want to be more careful if you find yourself towing a lot and running real high diff oil temps. In theory, the FM treated oil will go south faster in that situation. Likely still within a reasonable OCI, but worth mentioning.
 
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