What did you do to your Hellcat today?

[jgilj]

That gear has 1800 miles , didn’t last long ZF make junk rear differential in my opinion.

 

[2ndAmend]

That gear has 1800 miles , didn’t last long ZF make junk rear differential in my opinion.

What are you replacing it with?

 

[jgilj]

Another ZF gearset
From east coast moparts

 

[DGatzby]

That sucks. Break it in easy I guess. Mine howls a bit at about 45-50, but is not bad. The ‘15 sucked.

 

[jgilj]

I definitely have run it hard at least it never broke the case 😯

 

[Jimmy N.]

Does anybody have properly broken in gear set that ended up making noise?

 

[Unholy707]

Does anybody have properly broken in gear set that ended up making noise?

Launch control is active at 500 miles

 

[Bowlerguy92]

Trailered it nearly 6 hours to PA in preparation for RaceMotive on Sunday at Pocono Raceway. Staying at Aquatopia with the family about 25 minutes from the track. Should be a fun day in the water tomorrow and then racing on Sunday. View attachment IMG_0010.jpeg

 

[Jimmy N.]

Launch control is active at 500 miles

So? Have you ever read the gear break-in procedures recommended by gear manufacturers and larger resellers?

As it happens, today I took the first 20-mile drive (at lower speeds) to get the first of several work hardening cycles done in my new Durango. That'll be followed by four or five more short drives and cooldown periods.

Of course, that was after checking the fluid levels in the diffs and transfer case and installing magnetic level plugs. At 500 miles or so I'll check the magnets and put fresh (and better) fluid in the diffs.

And after the first 100 or so miles, I start going by the factory recommended break-in for the rest of the drivetrain. But I absolutely can't stand noisy gears, so those first 100 miles are crucial to me.

 

[Unholy707]

So? Have you ever read the gear break-in procedures recommended by gear manufacturers and larger resellers?

As it happens, today I took the first 20-mile drive (at lower speeds) to get the first of several work hardening cycles done in my new Durango. That'll be followed by four or five more short drives and cooldown periods.

Of course, that was after checking the fluid levels in the diffs and transfer case and installing magnetic level plugs. At 500 miles or so I'll check the magnets and put fresh (and better) fluid in the diffs.

And after the first 100 or so miles, I start going by the factory recommended break-in for the rest of the drivetrain. But I absolutely can't stand noisy gears, so those first 100 miles are crucial to me.

No, and neither do 99% of car owners. If it's not in the owners manual it's not part of the car's break in procedure. Not saying you're wrong, but very few are going to research the manufacturer of the gear set and their recommended break in for the gears themselves. What I'm saving is 500 miles is the break in period and shouldn't be beat on before then, which would also cover those first 100 miles

 

[Unholy707]

I've had 3 different diffs and they've all gotten noises regardless, but yes they've all been raced

 

[1971demon]

So? Have you ever read the gear break-in procedures recommended by gear manufacturers and larger resellers?

As it happens, today I took the first 20-mile drive (at lower speeds) to get the first of several work hardening cycles done in my new Durango. That'll be followed by four or five more short drives and cooldown periods.

Of course, that was after checking the fluid levels in the diffs and transfer case and installing magnetic level plugs. At 500 miles or so I'll check the magnets and put fresh (and better) fluid in the diffs.

And after the first 100 or so miles, I start going by the factory recommended break-in for the rest of the drivetrain. But I absolutely can't stand noisy gears, so those first 100 miles are crucial to me.

All my cars are un modded...(never raced)...I follow recommended break in procedures...I've never experienced any unusual gear/rear end noises ever...but my cars are low mileage for what that's worth...

 

[jgilj]

3300 miles on mine , I’m on the 3rd now. Factory installed one had proper break in I took it easy till 500 miles then it hit the track. Started making noise @ approximately 800 miles then replaced by dealership at 1200 . This is the last one next will be car going down the road.

 

[Unholy707]

Mine always started making noise right after the track. Would usually go away, but more track passes you make the more constant the groan will be

 

[jgilj]

I agree 100% it would quite down then start screaming again. The factory one was the worse, this last one was just loud couldn’t hear my classic rock!

 

[Unholy707]

I agree 100% it would quite down then start screaming again. The factory one was the worse, this last one was just loud couldn’t hear my classic rock!

I have long tube headers and poly engine mounts and I still hear it, this one I got used though and it was used at the track a lot so whined right away. I'll get my use out of it and then get a redeye one when it goes or put a hellcat spec one in it. I believe this is the 392 spec one, the prices are different for all 3 but I've never seen a comparison between the newer hellcat one and the 5.7/6.4 one people would swap to before it was a factory option

 

[Jimmy N.]

No, and neither do 99% of car owners. If it's not in the owners manual it's not part of the car's break in procedure. Not saying you're wrong, but very few are going to research the manufacturer of the gear set and their recommended break in for the gears themselves.

Except for the first few gear sets I've bought, they've all come with instructions for the break-in.

And they differ a little between manufacturers, so I've taken the most cautious approach by using the most miles, lowest speeds, most heat cycles, etc., basically creating my own formula for quiet gears. Yes, those first 100 miles are a bit painful, but the reward is that almost all of our vehicles (and it's been quite a few in the past 15 years) has or has had no kind of gear noise. The one exception was a '14 Ram 2500 which howled from the very start. It got traded in with less than 400 miles on it.

So why isn't gear break-in mentioned in the manual? Hell, when 24 pages are devoted to installing child seats there's not much space left. Plus I'd guess that not many follow even the basic break-in that is in the manual. Who wants to endure such a hardship? It's bad enough if the automatic wipers don't come on fast enough, or the car can't be remote started from 500 feet away.

Basically, cars are made for idiots now, with features dreamed up by focus groups residing in their parent's basements. So just like with a computer, bullshit in results in bullshit out.

 

[2ndAmend]

I broke in a 3.70, 3.90 and a 2.62, never noticed any noise at all from any. I drive extremely gently 99% of the time regardless.

Note: If the perpetual tinnitus is the same frequency as the diff, I wouldn't be able to tell!

 

[Unholy707]

Installed my 2.50 pulley. AAD idler bracket threads are way too shallow and soft for the 35 ft lbs they call for. Pulled threads on 2 of the holes with less than 25 ft lbs per my digital torque wrench on 1 and clicker torque wrench on the other - no way they're both bad. repaired better than new with helicoil, now takes the 35ft lbs no problem. If anyone is wondering, the size for the bolt that goes through the idler pulley to the bracket is M10 x 1.5. Any expensive aluminum part should have helicoils for additional strength period.

 

[2ndAmend]

Installed my 2.50 pulley. AAD idler bracket threads are way too shallow and soft for the 35 ft lbs they call for. Pulled threads on 2 of the holes with less than 25 ft lbs per my digital torque wrench on 1 and clicker torque wrench on the other - no way they're both bad. repaired better than new with helicoil, now takes the 35ft lbs no problem. If anyone is wondering, the size for the bolt that goes through the idler pulley to the bracket is M10 x 1.5. Any expensive aluminum part should have helicoils for additional strength period.

Just a general sub-note: Rule of thumb is you need 3 diameters of thread engagement (depth) in alum to account for the approx 3x difference on strength. I try to use the longest screw that will fit and try for 3.5-4x. Shorter engagements definitely need steel inserts, but the inserts still need 1.5-2x min engagement.