Breaking in a LSD

[Skylarking]

Many threads exist around diffs but I haven't seen break in prodedures discussed in any detail, just diff ratios and such....

I've read that a number of figure 8's should be done to help distrbute the diff oil between the clutch packs after a LSD rebuild.

The owners manual states the new vehicle run in procedure. That section defines how the new car should be driven during its first 1000kms (light throttle, avoid downshifting, don't drive at constant speed, moderate acceleration in lower gears only and avoid speeds above 110kph) and from from 1000kms to 5000kms (heavy acceleration in lower gears may be used and vehcile speeds above 110 should be limited to 5 minutes per use). Also it states to avoid towing for the first 1500kms else speeds must be below 80kph...

So what precautions should one take in breaking in a rebuilt clutch pack LSD to avoid whines. When should the diff oil be changed?

 

[hademall]

Many threads exist around diffs but I haven't seen break in prodedures discussed in any detail, just diff ratios and such....

I've read that a number of figure 8's should be done to help distrbute the diff oil between the clutch packs after a LSD rebuild.

The owners manual states the new vehicle run in procedure. That section defines how the new car should be driven during its first 1000kms (light throttle, avoid downshifting, don't drive at constant speed, moderate acceleration in lower gears only and avoid speeds above 110kph) and from from 1000kms to 5000kms (heavy acceleration in lower gears may be used and vehcile speeds above 110 should be limited to 5 minutes per use). Also it states to avoid towing for the first 1500kms else speeds must be below 80kph...

So what precautions should one take in breaking in a rebuilt clutch pack LSD to avoid whines. When should the diff oil be changed?

I’m out.

 

[Skylarking]

I’m out.

Thanks for your contribution.

Close the door behind you

 

[Immortality]

I don't think clutch packs will cause a whine as such. The clutch packs only slip when the rear wheels are turning at a different speed, aka when going around a corner so during regular driving all the internals in the diff center are stationary.

The diff shop that rebuilt my LSD had me do a couple of complete turns in either direction at full lock to force the friction surfaces to slip and allow the oil to work into it. After that the instruction was to let rip which I followed by a long burnout going up his driveway.

Seeing as clutch packs wear out and contaminate the oil, more regular changes would be advisable to remove this contamination/grinding paste from the diff case.

 

[losh1971]

When I had my D35 rebuilt I was told same as Mort, do a couple hard tight lefts and a couple of hard rights to push it together and call it done. Also like Mort said keep up the oil changes. I assume you have the average at best stock LSD and not an ultra trick one like a Kaaz.

 

[lmoengnr]

Rebuild the diff with a Truetrac instead of clutch packs.

 

[losh1971]

If the OP does have a stock ZF clutch pack fitted and he paid for it, the diff tech should be shot lol. There are much better options in the way of clutch packs, albeit more expensive but you'll only do it once.

My diff tech said the clutch pack centres he fits to heaps of diffs are better than a Harrop. He said to me fit one of these and you never fit a Harrop ever again. Me I'm not wanting a $4.5k diff, so will opt to have my SH low KM centre fitted when it comes time.

 

[daves8]

Many threads exist around diffs but I haven't seen break in prodedures discussed in any detail, just diff ratios and such....

I've read that a number of figure 8's should be done to help distrbute the diff oil between the clutch packs after a LSD rebuild.

The owners manual states the new vehicle run in procedure. That section defines how the new car should be driven during its first 1000kms (light throttle, avoid downshifting, don't drive at constant speed, moderate acceleration in lower gears only and avoid speeds above 110kph) and from from 1000kms to 5000kms (heavy acceleration in lower gears may be used and vehcile speeds above 110 should be limited to 5 minutes per use). Also it states to avoid towing for the first 1500kms else speeds must be below 80kph...

So what precautions should one take in breaking in a rebuilt clutch pack LSD to avoid whines. When should the diff oil be changed?

When I had my new LSD put in, I was told to drive it for 10-15 mins, keeping speed below 80, heat up the oil then let it cool for a few hours. I was to do this the first few hundred kms from memory

 

[VYCommodore76]

I've only ever had to do the figure 8 thing with a KAAZ

 

[Skylarking]

I don't think clutch packs will cause a whine as such. The clutch packs only slip when the rear wheels are turning at a different speed, aka when going around a corner so during regular driving all the internals in the diff center are stationary.

The diff shop that rebuilt my LSD had me do a couple of complete turns in either direction at full lock to force the friction surfaces to slip and allow the oil to work into it. After that the instruction was to let rip which I followed by a long burnout going up his driveway.

Seeing as clutch packs wear out and contaminate the oil, more regular changes would be advisable to remove this contamination/grinding paste from the diff case.

Correct, clutch packs wont cause a whine. Chatter, clunks and knocks yes but whine no

The whine in my rather low milage diff was due to who knows what, may be poor pinion to ring backlash from factory or poor breakin procedure or something to do with the bind up and clunks that couldn't be eproduced at service... and the fact i don't believe the oil was changed by the dealer.

After a number of complaints, the dealer tech could finally hear the whine and then dumped some oil to find there was lots of metal specs found within the oil. So the dealer replaced the factory diff with a new factory diff which they said comes dry?

They said they did the figure 8's on their test drive to ensure all clutch packs were correctly lubricated and I should not drive it > 80kph for 5,000kms... Seems a bit over the top from a breaking perspective really....

If the OP does have a stock ZF clutch pack fitted and he paid for it, the diff tech should be shot lol.

As is, it was a warranty job so when the subject of what could be put in was broached, the dealer wouldn't enertain much as they wanted to keep keep warrenty work and other work separate. I'd have liked a Truetrac centre and a ratio change but I wasn't willing to pay for the whole job .... now ...

I'll assess how the diff performs from a noise perspective over the next 5000kms, which on past performance will take another couple of years... Then i'll revisit the issue of diff centre and ratio change

For the moment it's breaking procedures for the factory clucth pack LSD I'm interested in It sound like there aren't any consistant methods used and I'd have thought it would be standard across most manufactures