4.10 break in

[KiokenM3]

is there a faster way to break in the 4.10? i know you have to do the 1200 miles then the fluids swap, but is there anything else i can do to break it in sooner? i thought i saw somthing on another post doing a figure 8 to break it in, is that right?

[J08M3]

I don't think you need to do a break in since the diff really isn't new when you buy it. If you bought the Dinan diff it's only had the ring and pinion changed and break in isn't necessary. It's a diff that was returned by someone else. If you changed the gears on your current diff then you already know if you did the break in. The break in is for the clutches in the rear not the gears....

Correct me if I'm wrong??? I'm not positive on this.

[McLuVan]

I think the figure 8 is for clutch type clutches, not sure though

[Eugene-TAIWAN]

I don't really think the cars need to be broken in. At least that was what the BMW people tell me.

What I did was

1000KM = 622 miles keeping the revs under 4000 rpm

but when I get close to 622 miles I start pushing up 5000 rpm then little by little until I reach 622 miles. Right after I change the engine oil right away and added a couple bottles of X1R

[KiokenM3]

Originally Posted by Eugene-TAIWAN

I don't really think the cars need to be broken in. At least that was what the BMW people tell me.

What I did was

1000KM = 622 miles keeping the revs under 4000 rpm

but when I get close to 622 miles I start pushing up 5000 rpm then little by little until I reach 622 miles. Right after I change the engine oil right away and added a couple bottles of X1R

im not talking about engine break in, im talking about the rear diff break in.

[KiokenM3]

Originally Posted by J08M3

I don't think you need to do a break in since the diff really isn't new when you buy it. If you bought the Dinan diff it's only had the ring and pinion changed and break in isn't necessary. It's a diff that was returned by someone else. If you changed the gears on your current diff then you already know if you did the break in. The break in is for the clutches in the rear not the gears....

Correct me if I'm wrong??? I'm not positive on this.

so i should be able to start running my car hard as soon as i pick it up with the new gears?

[Eugene-TAIWAN]

Originally Posted by KiokenM3

im not talking about engine break in, im talking about the rear diff break in.

Sorry, There is not break in needed for the diff!!

I had a LSD installed my previous ride. I got the car in the afternoon and went to the race track the next day.

[KiokenM3]

Originally Posted by Eugene-TAIWAN

Sorry, There is not break in needed for the diff!!

I had a LSD installed my previous ride. I got the car in the afternoon and went to the race track the next day.

right on eugene

[KiokenM3]

so whats the reason for the oil change at 1200 miles?

[J08M3]

Originally Posted by KiokenM3

so whats the reason for the oil change at 1200 miles?

it's for the clutches in the rear diff.

[KiokenM3]

so there wont be any damage if i start running my car hard?

[stylinexpat]

I was doing donuts the second day after I had them installed in both my 130i and my old 330 ZHP No problems what so ever

[CanM3]

of course there is a break in with a new gear set......the ring and pinion have to establish a wear pattern on each other and they have to go thru a few heat cycles during this time period before they can be heavily loaded.
the oil change is designed to rid the oil of any metal contaminants that WILL be there after the break in cycle.
the engine rpm's really dont come into play as much as speed and acceleration. Whenever we installed new ring and pinions, the manufacturer would advise no hard acceleration for the first 500km's, no towing for the first 1000 km's, and no going over 120km/hr for the first 500 kms.
After picking up from the shop, try not to drive more than 100 kms and then let the vehicle sit for around 6 hrs.....to allow the diff to cool (a heat cycle).
The contact surfaces on a ring and pinion are surface hardened, if this hardening is damaged during breakin, when tolerances are tighter, the problems wont show up for some time.

You can get in a vehicle and romp on it right away, but the chances are higher of wiping the tooth contact areas on the gearset..

Also, the pinion bearings and diff case bearings need time to seat. They are installed with a pretty good preload on the bearings, so there will be alot of heat generated for the first little while. I'm sure the Dinan diffs have new bearings as well as a new gear set...they would probably go thru the diff case and inspect the posi internals as well as the spider/side gears..

[J08M3]

Originally Posted by CanM3

of course there is a break in with a new gear set......the ring and pinion have to establish a wear pattern on each other and they have to go thru a few heat cycles during this time period before they can be heavily loaded.
the oil change is designed to rid the oil of any metal contaminants that WILL be there after the break in cycle.
the engine rpm's really dont come into play as much as speed and acceleration. Whenever we installed new ring and pinions, the manufacturer would advise no hard acceleration for the first 500km's, no towing for the first 1000 km's, and no going over 120km/hr for the first 500 kms.
After picking up from the shop, try not to drive more than 100 kms and then let the vehicle sit for around 6 hrs.....to allow the diff to cool (a heat cycle).
The contact surfaces on a ring and pinion are surface hardened, if this hardening is damaged during breakin, when tolerances are tighter, the problems wont show up for some time.

You can get in a vehicle and romp on it right away, but the chances are higher of wiping the tooth contact areas on the gearset..

Also, the pinion bearings and diff case bearings need time to seat. They are installed with a pretty good preload on the bearings, so there will be alot of heat generated for the first little while. I'm sure the Dinan diffs have new bearings as well as a new gear set...they would probably go thru the diff case and inspect the posi internals as well as the spider/side gears..

good point. thanks for sharing

[KiokenM3]

Originally Posted by CanM3

of course there is a break in with a new gear set......the ring and pinion have to establish a wear pattern on each other and they have to go thru a few heat cycles during this time period before they can be heavily loaded.
the oil change is designed to rid the oil of any metal contaminants that WILL be there after the break in cycle.
the engine rpm's really dont come into play as much as speed and acceleration. Whenever we installed new ring and pinions, the manufacturer would advise no hard acceleration for the first 500km's, no towing for the first 1000 km's, and no going over 120km/hr for the first 500 kms.
After picking up from the shop, try not to drive more than 100 kms and then let the vehicle sit for around 6 hrs.....to allow the diff to cool (a heat cycle).
The contact surfaces on a ring and pinion are surface hardened, if this hardening is damaged during breakin, when tolerances are tighter, the problems wont show up for some time.

You can get in a vehicle and romp on it right away, but the chances are higher of wiping the tooth contact areas on the gearset..

Also, the pinion bearings and diff case bearings need time to seat. They are installed with a pretty good preload on the bearings, so there will be alot of heat generated for the first little while. I'm sure the Dinan diffs have new bearings as well as a new gear set...they would probably go thru the diff case and inspect the posi internals as well as the spider/side gears..

good info, thanks. i guess i'll take it easy for a few hundred miles, then get on it

[eeeboy]

Dinan told me easy the first 300 miles..

[dcstep]

Originally Posted by eeeboy

Dinan told me easy the first 300 miles..

Dinan told me and my installer 1200 miles, in writing. Since the installer was my dealer I stuck to that.

I'm glad to see that the thread is making some sense after a lot of bad information initially. This is a new gear set and DOES need break in.

BTW, how much added noise are you guys getting from your 4.10s? I'm getting a little gear whine on the overrun when in any gear other than sixth. It's not real loud, but you can indeed hear it. Changing the fluid after break in didn't really change the sound level.

Dave

[Green///Hell]

CanM3 is right, on my last two diffs I did the same thing especially because they were Quaiffe's

Last one I was advised by Fall-Line after a full day of hard driving at the race track and cool down, I changed the fluid.

The seals for the diff case I think are still using a gel instead of an actual seal after it was updated on the E46

[KiokenM3]

Originally Posted by dcstep

Dinan told me and my installer 1200 miles, in writing. Since the installer was my dealer I stuck to that.

I'm glad to see that the thread is making some sense after a lot of bad information initially. This is a new gear set and DOES need break in.

BTW, how much added noise are you guys getting from your 4.10s? I'm getting a little gear whine on the overrun when in any gear other than sixth. It's not real loud, but you can indeed hear it. Changing the fluid after break in didn't really change the sound level.

Dave

Right on dc, i'll follow the 1200 miles to be on the safe side