MWC fab 9 break in
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A 9" gear builds alot of heat by it's design nature, thus making the break-in procedure that much more important with this style rearend. If you talk to the gear manufacturers, they will tell you that 95% of all the returned gears are from improper break-in. They will actually cut the gears apart and check the hardness depth to verify the situation.
The absolute worst thing anyone can do is go out and immediately beat on the car with a new gear installed... no matter what rearend is in it. The point here is to bring the gears up to operating temp slowly, and then let them cool slowly... several times. Any clutch dumps, burnouts, excessive highway mileage, etc.before the surface tempering is done will do nothing but damage your new investment.
Do the 5 15 minute drives with an hour cool down in between have to be run in succession or can I do a couple a day? 30 mph tops correct?
I'm scheduled to have a dyno tune on the 11th; is this ok to do since it won't require hard launching?
One more question.. how many quarts of 80w90 will I need?
Hope to have it installed tonight

Thanks...
Last edited by 97ss497; Jun 27, 2011 at 11:43 AM.
Do the 5 15 minute drives with an hour cool down in between have to be run in succession or can I do a couple a day? 30 mph tops correct?
I'm scheduled to have a dyno tune on the 11th; is this ok to do since it won't require hard launching?
One more question.. how many quarts of 80w90 will I need?
Hope to have it installed tonight

Thanks...
It takes a little over 3qts.
Do the 5 15 minute drives with an hour cool down in between have to be run in succession or can I do a couple a day? 30 mph tops correct?
One more question.. how many quarts of 80w90 will I need?
It takes a little over 3qts.
And also, what fluid do you guys recommend? I know non-synthetic, but any particular brand over another? Anything that Autozone, O'reillys or Advanced Auto carries? Thanks!
As for Excessive there is no correct right or wrong with this, we just suggest not trying to do all 500 miles in one driving secession. After the first 15 minute cycles take the car for a cruise around town and give it time to cool off. Do that a few times and you will be up on your 500 miles in no time. While cruising just do not hop on the expressway and hold a certain speed for long periods of time until you are finished with the break in procedure.
As for fluids we have no recommendations, we suggest to our customers to use what they feel comfortable with.
***Five total heat cycles all done while lifted on jackstands off the ground at 15mph***
(1): 15 mins in drive as 1st cycle with an hour cool down after
(2): 15 mins in reverse as the 2nd cycle with an hour cool down after
(3): 15 mins in drive as 3rd cycle with an hour cool down after
(4): 15 mins in reverse as 4th cycle with an hour cool down after
(5): 15 mins in drive as 5th cycle with an hour cool down after to finish it off
Once jackstand session is complete, regular driving for the first 500 miles, no prolonged highway driving, or any amount of time spent at a constant RPM.






