DIY - Differential and Ring & Pinion Swap

[Dustin]

Pinion is FINALLY set. But I'm an idiot and forgot to order the shims to set the backlash on the differential. This WILL get finished eventually. First post updated. Stay tuned.

[FIGS]

So perhaps I missed it because I came into this thread referred by my.is but having recently done the OSGiken swap in our drift car I am curious...
Why did you need to replace the side bearings or did you reuse? It was unclear if you were installing the same conical thrust bearings or a different set. On the pinion, did you measure the gear engagement and decide you needed to reshim? Typically the precision on these Japanese units is such that no shimming is required.

Also the carrier looks remarkably like the IS300 housing. I just made some modular bushings for that case, I wonder if they will swap into this one.
Mike

[Dustin]

I replaced all bearings and seals for peace of mind. The factory bearings and seals already had 20k miles on them. Would they have been okay to use? I'll leave that for each person to determine themselves. For me it was worth it to spend the extra money to have all new.

I haven't installed the ring gear and new differential yet, so all I measured was the amount of force it took to spin the pinion gear by itself. According to the factory service manual it should take between 9.8 and 16.9 in./lbs. to move the pinion. That is what determined how much shimming I needed to have.

I'm no sure what you mean by no shimming required. This is the only rear end I've done so far and it would not be possible without shims. That being said, my brother has put together a few other rear ends where he used a different method where shimming is not required, however I am unfamiliar with this and do not think it possible on this setup.

[charged86]

I will not be doing this for my self! looks tough

[Dustin]

It is, but honestly, knowing what I know now, there should be no reason why I couldn't have this done over a weekend. My biggest drawback so far is not being prepared with all the correct tools and parts. Waiting on an in./lbs. torque wrench for a week held me up. Forgetting to order the shims for the differential is setting me back. Not to mention I only just returned to work today after being pretty much stuck in bed for over a week eff'd me down as well. Still no regrets on doing the work myself. Can't wait to get the last couple of parts to finish it up and get everything installed.

[FIGS]

Originally Posted by Dustin

I replaced all bearings and seals for peace of mind. The factory bearings and seals already had 20k miles on them. Would they have been okay to use? I'll leave that for each person to determine themselves. For me it was worth it to spend the extra money to have all new.

I haven't installed the ring gear and new differential yet, so all I measured was the amount of force it took to spin the pinion gear by itself. According to the factory service manual it should take between 9.8 and 16.9 in./lbs. to move the pinion. That is what determined how much shimming I needed to have.

I'm no sure what you mean by no shimming required. This is the only rear end I've done so far and it would not be possible without shims. That being said, my brother has put together a few other rear ends where he used a different method where shimming is not required, however I am unfamiliar with this and do not think it possible on this setup.

well 20K is nothing on bearings that are not under a lot of load and not exposed to a significant amount of heat. I just pulled some out of a car with 112K miles that was driven pretty hard with a supercharger and they hardly had any wear.


By shimming I meant you should have been able to swap the diff without touching the pinion at all and chances are the lateral shims for the axle bearings would have worked as well. If you read the FSM it implies that all of these things are required (really because you are in the section about servicing the rear differential). But if you look at the goals for what you are doing its just to add the clutch LSD function, not change gear ratios...unless I missed something you are also changing gear ratios .


but in any case its always cool to see people going outside their comfort zone as I have to make it a regular occurrence to do what I do. With the proper tools nothing is complicated, just time consuming and detailed.
Mike

[Dustin]

I guess I never stated that I'm going from a 4.10 to a 4.56, plus I used a solid pinion spacer instead of a crush sleeve. I already tried using the factory lateral shims. No way were they gonna work. There was no movement at all in the differential. Regarding the bearings again, I'll leave that to each person to decide if they need to be replaced. Could I have used the ones in there? Yes. But everything else going in was going to be new., so for peace of mind, I went with all new. Thanks for your input though. I appreciate the advice.

[gk]

So I'm still new to this, but can anyone explain to me what the shims are and their purpose? Pics would also be greatly appreciated

[Dustin]

CORRECTED** Thank you @Dipstik-sportech for correcting me. These are the shims for the pinion. You use them to set the preload on the bearing. If it is not set correctly, it will either spin too freely or be more difficult to spin.





This is the shim I used for setting the pinion depth. It goes in between the pinion gear and the pinion bearing. This is the one that determines how far into the carrier the pinion goes.





It goes here




I don't have pictures of the shims for the differential, but what they do is position the differential and ring gear left to right to get make sure you get proper contact between the ring gear and pinion gear. Too far one way or the other and you either have too much contact or not enough.

[Dipstik-sportech]

Correct me if I'm wrong but those shims are for adjusting bearing preload not pinion depth. Pinion depth is set by the size of shim between the pinion gear itself and the inner bearing not between the inner and outer bearings.

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[Dustin]

Originally Posted by Dipstik-sportech

Correct me if I'm wrong but those shims are for adjusting bearing preload not pinion depth. Pinion depth is set by the size of shim between the pinion gear itself and the inner bearing not between the inner and outer bearings.

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That is right. Thank you for correcting me.

[Dipstik-sportech]

Not trying to be a douche or anything just pointing out lol

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[Dustin]

Lol, no douchyness. A genuine thank you for pointing it out.

[Dustin]

Found out earlier today that I should be having a nice stack of shims coming my way for the differential. Thanks to Gordo from jzxproject.com for helping me out of a jam. Maybe this will be done next week??