Rear gear break in period

[turboscrew]

I bought a set of 3.73s that had about 1,000 miles on them. They look good with no wear and almost look brand new. My question is, Should I break them in after the install or will they be ok since they have already been ran? If I do need to break them in what is the proper way to do this?

 

[try2catchmy99]

Im not a expert but I would say break them in again because when installed in your diff the gears most likley will not be exacty installed and shimed as they were in the previous diff and most likely there will be a new wear pattern.

 

[Jackie Chan]

i broke 3 sets of gears in by taking them to the drag strip....no problems. the install is the only key to the deal. no beak in rquired on weak ass ratios like we use

 

[Cobra Jay]

Im not a expert but I would say break them in again because when installed in your diff the gears most likley will not be exacty installed and shimed as they were in the previous diff and most likely there will be a new wear pattern.

Actually, a pattern is already there once the R&P is lapped together. Install and shimming only makes sure that they mesh correctly.


BREAK-IN


With 1,000 miles on them they'll be fine, just make sure the pattern is right.
On new gears, some say yes, some no. Personally from what I've been told, 150-200 miles is a good breakin period for gears. That's what I did and that's what I reccomend. I got my info from FORD engineers and garage mechanics at the axle plant.

 

[try2catchmy99]

Yeah I wasent sure
I was guessing that wear might be off a little from the first installation
I was just thinking better safe then sorry

I just had my 430s, 31 axles and diiff installed and I went ahead and broke them in for 400 because I have heard so many people including myself that didnt break them in and shortly after they started whinning bad. Plus thats what my gear installer suggested, and he mostly does mustangs, f bodies and cars that see drag strips and road courses.

But some can get away with not breaking them in at all.

But first off the installation has to be right, bad installation and your doomed from the start.