My son out in CA called me about this. He has a '99 Ford F350 that has a severe clunk in the driveline when shifting into gear. He said he has a little vertical slop in the pinion (up/down) of the rear end,and some slop in and out of the pinion. Also he has a touch of slop up and down in the slip yoke. I told him if this was a GM rear,for sure it is junk,but-
OK,never having owned,or rebuilt a Ford rear end,I ASSUME this is no good,Correct?

He said he thinks it as a 10.5 rear,if that helps.
Thanks.
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‘63 LeMans- ‘69 400 w/ original transaxle. 2.69 gears.
‘55 Catalina
‘62 Mercury Meteor-all original, bought new by my grandfather
71' GTO -original 400/4-speed/3.23 posi
13.95 @ 102.1 on street tires @ 4055lbs.-now my sons ride