I have a 1999 Dodge Ram 1500 Sport with a 5.9 Magnum engine. Rear axle is a Chrysler 9.25. I need to replace the rear drive pinion seal and drive pinon bearing. I know i can just drop the drive shaft to replace the seal but do i have to drop the whole axle to replace the pinion bearing? Also should i replace the CUP pinion bearing while im at it? The gears are all still in great shape inside the rear diff but im getting a slight leak from the seal and the drive shaft has more wiggle than it should when i jerk on it by hand. Any info would be extremely helpful. (Parts to replace are #4,#5,#6 possibly.

 

The bearing, 5, is easily replaced when you are doing the seal. Getting the cup out can be a real challenge though, without tearing the whole thing apart. See what it looks like, take it from there.

 

thank you!

 

The bearing is pressed on the pinion gear shaft and there is no space to get a puller on it while in the diff. You have to hit the pinion shaft itself to get the front bearing out, which requires the carrier to be out of the case, so everything would have to be apart.

If you just want to do the seal, you must mark the relative position of the big pinion nut to the shaft itself. There is a crush sleeve in the 9.25 and loosening the nut will release the proper preload from the bearings. You can save yourself from needing to replace the crush sleeve (which again would require complete disassembly) by tightening the pinion nut slightly further than it was when it came off (hence needing to mark relative position). This will make the bearing preload tighter but likely still within spec, and ensure that the nut is actually tight enough. You'll probably need to crank on the nut pretty hard so make sure not to go too far.

 

Thank you Oxymoron,

One more question, if my outer bearing is toast then is it safe to assume that my inner bearing is as well?. I would think that the amount of play the yoke has would indicate bearings on both ends of the pinion shaft being shot. Not the best with terminology so I hope that makes sense..

And thanks for the info about tightening the bolt a little extra to avoid replacing the crush sleeve.

 

Part 31 as well as part 5 above, to clarify a bit

 

I have never had to disassemble the diff to get the front pinion bearing off. And I have done a fair few of 'em......

 

So i shouldn't have to disassemble to replace either bearing, 5 and 31?

 

31 is indeed pressed on, and you have to completely disassemble things to get it out.

 

Thanks, that's what i thought after taking a look in there. I guess ill get a couple crush sleeves and give it a shot this weekend