Uneven Drive Flange Wear?? WTF?

[Boston Mangler]

well, i finally got my front end totally disassembled and ready for the rebuild

one thing i noticed that was odd, was the wear of the drive flanges

the drivers side is in awesome shape (both the birf and the flange)

however, the passenger side flange is VERY worn and the birf is worn (at the splines) slightly

curious what causes this and if i should be concerned

i am going to replace the flange for sure, but should i be concern about the slight wearing on the birf? possibly weakened? it is a very small amount, but worn nonetheless

thanks
kevin

 

[-Spike-]

Splines wear exponentially. Once a tiny amount of play is present, they rapidly deteriorate. I'd take this opportunity to replace the birfs too, and keep the good one (or both) as a trail spare.

-Spike

 

[psfpilot]

Same wear pattern here on our 92. My birf was swapped out for a Longfield, though I seem to recall that someone on 'Mud recently claimed that Bobby himself recommended the Japanese birf for DD highway use because it's harder metal for better wear.

FYI, the late-94+ longer-splined drive flange is what matches the Longfield. CDan also had my short-spline flange in stock, vice the 2+ week wait from my local dealer. Here's a thread on flange & birf wear.

 

[IBCRUSN]

Some of the other that have been around longer may be able to confirm or deny this but I read somewhere that there were issues with drive flanges at one time. Some were better than others. I would imagine that it could have been the metalurgy of certain batches. Maybe (more likely than not) Dan has the answer.

 

[Boston Mangler]

Here's a thread on flange & birf wear.

Excellent Info! Thanks!