Gears & Axles - Gear install - pinion preload issues
04-09-2012, 02:49 PM
I've got myself a spare axle that I'm putting 4.10's into. It was originally a 2.73.
I bought a Motive gear set, Ratech complete install kit and a solid spacer.
I'm at the point where I'm putting the pinion into the housing and torquing up the nut. My problem is that before I'm anywhere near halfway towards the specified 125 lb/ft the yoke gets very stiff.
I measured the old crush sleeve with calipers and made up the same thickness with shims and the solid spacer so I thought I'd be very close to perfect but apparently not. What am I doing wrong and how should I proceed?
Also how close is the yoke flange supposed to be to the oil seal? Mine is about 5mm away when the yoke stiffens up.
I'm reasonably sure that both bearing races are fully seated in the housing.
04-09-2012, 03:19 PM
Save yourself alot of grief and go buy another new outer pinion bearing and open up the ID so it's a slip fit on the pinion to use as a set-up bearing for the solid pinion spacer. I used my old bearing as a set-up bearing and when I installed the new bearing it threw off my solid spacer set-up. You really need a set-up bearing because to get the proper pinion rolling drag with the solid spacer takes alot of trial and error to have it set right when the pinion nut is torqued.
Grind the self locking feature off the old pinion nut and use that nut during set-up also. For the final torque of the pinion nut I took into account the drag of the self locking nut which in my case was 25 ftlbs. I added this to the Ratech solid spacer recommended torque of 125 ftlbs for a total of 150 ftlbs. This is routine in my industry, but do what you are comfortable doing.
04-09-2012, 03:20 PM
You need to add a shim to your solid crush sleeve. Very little does a lot with those tiny shims. Also, your final torque on the pinion nut WILL effect your pinion drag, so make it consistent each time you tighten it.
04-09-2012, 08:05 PM
The outer bearing was the only bearing that came out intact so maybe I'll give the I.D. a grind to make it loose and use that as a reference.
It sure seems counter-productive hammering the pinion out each time I decide things are not spot on.
The threads on the new pinion nut are getting torn to shreds, I assume its the cast in locking feature that is wearing and causing the chaff I'm seeing. I noticed the Ratech nut had a raised section of thread in the centre of the nut thread and assume this is the locking feature.
Each time I remove the nut there are splinters of stripped metal visible but I hope this is normal?
That raised section is gone now!! :eek2:
04-09-2012, 10:31 PM
Sorry buddy but your lack of experience is putting you in a bind. First, yes you need a non-locking nut to keep from tearing your pinion threads up. I used a spare that was the tapered type (stock I guess). Half of it fits the socket and the other half tapers down into like a funnel shape. The tapered section is where the lock is so I simply cut that off and filed it all smooth and I use it for mock ups. If you grind the ID of any bearing it is not suitable for service any longer. It can only be used as a mock up bearing. That means you need to use your old stocker for a mock up or buy two new pinion bearings (inner and outer) and sacrifice those for all your pre-assembly stuff.
04-09-2012, 11:25 PM
I'm also going to rain on your parade. When you're all finished figuring the proper preload you still have to find the correct pinion depth, and then set the proper backlash and preload on the ring gear and carrier.
Find someone with lots of experience to help you or have a qualified shop do it. Not some general auto repair, but a real differential shop.
You'll be money ahead when it's over. Just read all the other rear end problem posts in this section.
Al 95 Z28
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