My shop is swapping out my diff to an OSG unit. But he is concerned about how to remove the gear shaft snap ring. Alldata shows a special tool but he doesn't have it and isn't sure how to proceed.
any advice for removing the shaft snap rings ( ot axle ones) and reinstalling. Sorry if this doesn't make sense as I am not mechanically inclined 😊

 

No need for the tool to remove or install. But you do need some pretty stout snap ring pliers. My dad welded two needle bearings onto the jaws of some medium sized vicegrips and we had no problems disassembling or reassembling. Keep in mind, you'll want to fully cold soak the spool overnight in a freezer to shrink it as much as possible for the install, but removal is simple.

 

Here's more info with lots of pictures:

https://figsengineering.blogspot.com...-lock-tcd.html

http://figsengineering.blogspot.com/2016/08/revisiting-tcd-osgiken-lsd-installation.html

https://www.clublexus.com/forums/is-f-2008-2014/649874-figs-os-giken-lsd-swap-write-up.html

 

Should have just went with that Torsen aye? lol. Hope you get it sorted!

 

Is it only me or is the setting of the bearing preload missing in the installation reports? Or does everyone assume the spool size and new bearing size are exactly the same?

 

They have been so far. No one has needed to move the pinion gear or move the spool to get proper tooth alignment with the Giken spool. Mine was absolutely perfect on install with the same bearings and snap rings. It seems the OS Giken team have built the perfect fitment for our application.

 

To my knowledge a correct tooth pattern does not guarantee a correct bearing preload. Bearing preload, tooth pattern and back lash are all different parameters and need to measured separately.

 

There is no measurement for side bearing preload in the factory service manual. Pinion bearing yes, overall preload yes. No side preload.

 

That seems odd. There are about 40 snap rings available with 0.02mm increments. All Toyota/Lexus manuals i have seen carry a preload torque check for new and used bearing set.

 

Preload for the pinion, and overall preload, but the procedure for selecting the snap rings is based on backlash measurement only which implies if you had good backlash when you took it apart, and have good backlash after putting it back together, your snap ring selection is good. It does clearly say you need to measure backlash in three places, and the maximum deviation for those three measurements cannot exceed 0.05 mm (0.00197 in.)

When the rear differential side gear shaft snap ring thickness changes by 0.02 mm (0.000787 in.), the total preload will change by approximately 0.1 N*m (1 kgf*cm, 1 in.*lbf).
When the side gear shaft snap ring thickness changes by 0.02 mm (0.000787 in.), the backlash also changes by 0.02 mm (0.000787 in.).

So, the procedure is primarily focused on backlash being correct and assuming it isn't possible to have correct backlash and inadequate or excessive preload.

 

If the manual does not state preload measurement i would suggest to measure this before disassembly. I find it hard to accept that all the oem spools lenghts are already within 0.02mm on the bearing landings, not even considering the ring flange position. To change with aftermarket spool a 0.02mm or more difference will probably be found, The difference can result in backlash changes but also in preload change.

To adjust the backlash (or more important tooth pattern) i agree equal amounts of ring changes are required. But only when the bearing preload is set, these are tapered bearings after all. If the aftermarket spool measures the same lenght as the oem, than ok, but larger than 0.02mm difference i would consider to choose a different ring. But maybe that's just me adjusting to the max...

 

My tooth pattern was perfect, and the backlash was middle specification in all measurements. Runout was negligible. Giken's spool is as mechanically identical in fitment as one could hope. I have nearly 100.000 km on mine now and it has performed flawlessly.

 

I used this one when I did mine. Also didn't have to change snap ring thickness as gear lash and engagement was the same before and after.

 

Good to know the install of the OSG is pretty much straight forward!

 

Thanks for all of the feedback. That is consistent with what I am hearing from multiple people. Agree that it is a nice surprise that it is relatively without issue and straight forward. It should be done Monday!
Thanks again!