so I am piecing together a fj40. its a 77 body and frame, with a 350/sm465/ 72 fj40 3spd case. it has 77 axles under it, but the front pinion is broke off. I was already planning to swap a 72 chunk into the front to fix that. well I took my 72 driveshaft in today to get it lengthened for the rear. then got home and realized the rear pinion flange is a larger bolt pattern. so Do I need to just use my 72 rear back there, or is there an easy flange swap? I'm assuming its course/fine spline differences? I didn't have any 77 driveshafts.
driveshaft info 72/77
- Thread starter Gotta40
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replacement pinion flanges are available new inexpensively with whatever pattern you need. both 72/77 will be coarse spline but have different patterns as you've discovered.
as i understand it yes you can but you need to make sure you tighten the pinion nut EXACTLY the same number of turns at you take it off otherwise you’ll change your pinion preload and cause wear to the diff.
I don't think they were round pinion flanges till later... but if your flange is round, the flange can be turned 45* and re-drilled to the correct size. I have done this with my newer thirds out of a 60 series Landcruiser.
my 77 is not round and has no ability to drill.
i just did the opposite swap. a 77 h42 into a 72!! i had to find early pattern drive shafts and have them make a hybrid shaft when they lengthened them. 72 at the pinion end and 77 at the drive shaft end. there are round flanges you can buy that have multiple patterns on them. it’s just a matter of getting the pinion preload right when swapping it on
i just did the opposite swap. a 77 h42 into a 72!! i had to find early pattern drive shafts and have them make a hybrid shaft when they lengthened them. 72 at the pinion end and 77 at the drive shaft end. there are round flanges you can buy that have multiple patterns on them. it’s just a matter of getting the pinion preload right when swapping it on