Getting my diff rebuilt as we speak with new bearings, 4.77, etc. How do I properly break in my diff? I've looked and all s2ki tells me and people breaking the diff haha. But I need to know how to break in. Like how many miles? Easy miles or beat it good?


Another important question is oil. Should I get a break in oil or just go straight to the oil I plan to use? Should I change the oil after a certain amount of miles? Just ordered 1qt of amsoil 75w140, should I get another one for after the break in?
Thanks

 

Mine was drive slow with not a lot of load for 5oo miles and then change fluid .. Might be a certain oil to use for first full up too but not sure

 

same drive it easy for 500 miles and change oil, no special breakin oil, the Amsoil you picked is a great choice.

 

Ok thanks guys. So I should drive slow for the first 500 miles. Does this mean avoid the highway? Or can I just take it really easy on the highway?

About the oil... should I order another bottle of amsoil 75w140 for the 500 mile break in, or can I just use something decent for the first 500, then change it to my amsoil?

 

I'd stick to the same fluid (Amsoil).

 

Who ever is building your rear should have instructions for you. Here is some information I send to the owners I build for, good luck

Break in,

Be sure to rev match your shifts! When you launch the car preload the drive train, be smooth, and get some tire spin

Use a good quality GL-5 Hypoid 75/140 gear oil in the rear. Use this oil in the rear for 500 miles then drain.

Use Amsoil synthetic severe Gear 75/140 gear oil every 6K to 12K miles.

When you receive the rear, fill it with oil Be sure not to over fill the rear, fill the rear until the oil starts to come back out of the fill hole. Replace the fill bolt once the oil slows to a light trickle

More Break in:

Drive the car like a civilized human for 300 miles, No launching, power shifts, or hard down shifts. After 300 miles the rear is fully broke in and “normal” driving can begin.

 

Thanks puddymod! Always nice to get advice from the master themselves!

 

Also be sure you can remove the fill bolt first when you change the oil as it take some maneuvering/ the right tools to get to