locking diff for birf service

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Mar 17, 2006
Pacifica CA
I just cleaned/repacked my birfs. It was definitely time as one birf gushed out what appeared to black greasy oil only slightly thicker than the black oil in the diff.

I locked my diffs and then discovered that naturally the birfields flats did not line up properly for removal. So was I supposed to disconnect the front driveshaft in order to rotate the axle (since the rear wheels where on the ground)? When I unlocked the cdl the axle lockers also unlocked (according to the flashing light) so I did the job with an unlocked diff (which gave me no problems btw). What part of lock the front locker when pulling axles do I not understand?

Next I get to readjust the bearings as I think they are a bit too warm after my 50 mile highway drive in cool weather.
I have never locked the diff. when doing axle service. I'm not up to speed on why that would be necessary.
As far as I know, you don't have to lock the front diff to service the front axle, but you should lock the rear diff when servicing the rear axle. I didn't lock my front when I did the birf job.
The only time you need to lock the front diff when working on the front axle is if you are removing the diff from the housing. The locking cog has to be in the locked position to get it pulled out of the housing.

I have seen a couple of instances when I had trouble getting the short side (passenger) axle fully inserted into the diff, and cycling the locker a couple of times seemed to help.
Hi guys - I'm going in to replace my DS birf after doing damage last week :(
Anyway I'm reviewing the birf job info and recall reading that when pulling the front axles we are supposed to lock the front diff. This thread seems to suggest that it's not needed and might even create a problem when pulling the birf due to alignment of the flat side.

If it is recommended, are there any suggestions on getting the front locked when moving the truck around on my hard pavement driveway and garage?
I believe the FSM states to lock the diff before pulling the axle. If you not careful reincerting the axle you can knock the locking mechanism out of place. That said the first time I did the birfield repack I forgot to lock before hand. I was just careful putting them back in without problem. You do not want to activate the locker with the axle out. This applies to factory lockers only.

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