Ring gear backlash question

[RWBeringer4x4]

6. Finally, at the bottom of the stack, is the preload washer, tapered side down:

I measured the pre-load washer - looks like it's one of the thickest possible. Based on the FSM, it should be 90560-30199.

Does all of this look correct, in terms of install order/orientation? If so, I will move forward with finding (or making) a thinner preload washer. If something is way off, let me know! It will save me a lot more headaches! I've also ordered some additional shims. Hopefully with all that, I'll get the preload to actually exist!

 

[Pin_Head]

It looks right. I think that the bevel goes down, but it has been so long I'm not sure. I can't imagine it would really matter.

 

[RWBeringer4x4]

Thanks, as usual, for the rapid response, @Pin_Head! From a preload perspective, you're probably right, it shouldn't matter. Only reason I can see it mattering is that the flat side gives the thin shims more surface are to compress against...I figured this was probably right.

So for now I guess I'll wait for the replacement shims to arrive. I managed to find a place with 90560-30184 (the thinnest washer at 2.74-2.76mm) and 90560-30185 (the second thinnest at 2.77-2.79mm) in stock. We will see if they actually ship. Looks like you were right, everything in between those, and the two thickest, seem to be NLA.

I figure I will start with the thinnest one, and see where my preload ends up. If it's WAY overkill, It looks like I'll be sanding one of the thicker ones down to somewhere in between!

 

[RWBeringer4x4]

Damn! Looks like you were right, got notification this morning that all of these washers have been discontinued. I was holding out hopes I'd found a stockpile!

I guess at this point I'll have to risk grinding down the one washer I have...which doesn't make me particularly comfortable...

@Pin_Head - at this point, if I screw up sanding down this washer, what is my recourse? Sounds like I won't be finding any more of them, so I'm really hesitant to mess with the one I have...

 

[srgould41]

Several guys on here have lathes in their garages/shops. Seems to me there is a market for shims and people with the tools to make them.

 

[RWBeringer4x4]

Several guys on here have lathes in their garages/shops. Seems to me there is a market for shims and people with the tools to make them.

Obviously, I'm picking up what you're putting down there. I think the issue would be a cost vs. Time thing - These need to be precision milled to between 2.7mm and 3.0mm in 0.03 increments or so...They used to come in a set of 25...I'd imagine if the cost was much more than $5/washer, there would be way less interest...that's an awful lot of machining for very little ROI.

 

[thorslc1977]

I am the original owner of my Aug 77 build FJ40. I am doing the exact same thing for my rear diff. I started because i did not have any preload in the rear diff. I tried to measure preload while it was in the 40 but the awkward angle and the drag of the axles and everything else made getting an accurate reading impossible. You are exactly right on how the assembly is put together. That is exactly how mine was when I took it apart (I only had one shim also) and this the first and only time it has been apart ( again the advantage of being original owner). Today I am finishing a jig made of 1" plywood to mount to engine stand to make checking preload on pinion, carrier bearings and backlash easier and more importantly more accurate. SOR has shims that can be sanded I ordered some. I wonder if we can get Pin_Head to elaborate on the sanding method he used.

 

[RWBeringer4x4]

@thorslc1977 - thanks for chiming in - glad I'm barking up the right tree. I checked SOR for those shims, would you happen to have the part number? I couldn't find them! Pin_Head had elaborated on the sanding method earlier in the thread, see quote below:

The preload washer is the thick one. These came in a set of about 20 in increasing thickness by .001 and you just picked the one you need. I think that they are no longer available. You can thin them pretty quickly using 240 grit silicon carbide paper on a piece of flat glass with kerosene as a cutting fluid. It takes about 50 8 inch long strokes to sand off .001. Use a micrometer often. I don't think it will matter which side you sand. Maybe do both.

You can have 0-3 thin shims, depending on the thickness of the pinion depth shim.

 

[Pin_Head]

Sanding the shims is easy. You use 240 grit silicon carbide paper on a piece of flat plate glass and use mineral spirits as a cutting fluid. You do a few strokes, rotate the shim and do a few more. It takes about 50-100 strokes to shave off .001. Test it frequently. .001 change gives about 5 inch pounds of preload.

Toyota used the thin shims to compensate for changes in pinion depth after the preload was set. I don't know why they chose to do it this way. Set the preload first and then set the pinion depth. The thin shims correspond to the different thickness of the depth shims. If you increase the pinion depth shim, you remove a thin shim and visa versa.

If you take too much off the thick shim (unlikely if you check the thickness often) you can just add another thin shim and keep sanding.

Don't over think this. It is not rocket science. It is just tedious trial and error and you will get it right.

 

[RWBeringer4x4]

I guess I'll give it a shot - Sounds like a lot of trial and error in my future! Since my preload is effectively "zero" right now, there's really no way to tell when enough sanding is enough without repeatedly trying it in the diff. my concern is that I've found a thread or two where people kept sanding and sanding, and the preload never came up. Don't want to ruin the one washer I have...But at this point, I'm sort of between a rock and a hard place. You're probably right, I am most likely over-thinking this!

 

[Pin_Head]

You can be reasonably sure that the pinion preload was OK when it left the factory. The loss in preload must be due to wear. Because of this it should not take much sanding to get it back into spec. Just for grins you can try assembling it without the thin shim to see what preload is like. Tighten the pinion nut until you just start to feet drag. That will give you some idea of the maximum you will need to remove to get the preload in range.

 

[RWBeringer4x4]

@Pin_Head - You are a gentleman and a scholar, sir. Thanks for all the information. Maybe I'll try throwing it together without the thin shim and see if the preload comes up. If, by some miracle, it comes up "spot on" at 10 inch pounds with the nut torqued to spec, is it safe to run it without any thin shims? I think the rule of thumb was "0-3" thin shims, so I'm assuming this is OK.

 

[thorslc1977]

Thanks Mr. Pin_Head. Just like Mr. Beringer my diff made no noise. I am chasing clunk noise at shift (already eliminated driveline and u-joints also no play at T-case e-brake). So checking diff pinion nut noticed it loose and started me down this path. Hope to not have to set pinion depth I am hoping to just check/reset ring and pinion backlash; carrier bearing preload and pinion preload. I guess sort of tighten up and refresh more than anything else.( per ZUK's toyota gears install) The shims I got at SOR are .25 mm with Toyota markings. It looks to me that two put together will be a good starting point for me to set pinion preload as old worn shim measured about .40 mm. Mr Beringer I will look up part number later this morning.

 

[RWBeringer4x4]

The shims I got at SOR are .25 mm with Toyota markings. It looks to me that two put together will be a good starting point for me to set pinion preload as old worn shim measured about .40 mm. Mr Beringer I will look up part number later this morning.

Those sound to me like the "shims" and not the preload washer I'm referring to. There should be one thick washer (between ~2.75 and 3.0mm) and 0-3 shims (~0.25mm each). The shims are still available, the washers are not. Either way, I'd still appreciate the part number if you can find it, just to be safe! Thanks

 

[thorslc1977]

You are right Mr. Beringer. They are the shims--- SOR part #090-26A. And I am back asswards on shims /preload thing. I keep thinking adding shims will increase preload. It is just the opposite! So I am going to do what you are going to do --that is try with no shim and see where I land. If I have to sand thick washer --well OK -- and if I go too far it is like Pin_Head said just add new shim test fit and sand shim if necessary. Will finish jig tonight and start test fitting things tomorrow. Thanks for letting me butt in on this thread.

 

[RWBeringer4x4]

You are right Mr. Beringer. They are the shims--- SOR part #090-26A. And I am back asswards on shims /preload thing. I keep thinking adding shims will increase preload. It is just the opposite! So I am going to do what you are going to do --that is try with no shim and see where I land. If I have to sand thick washer --well OK -- and if I go too far it is like Pin_Head said just add new shim test fit and sand shim if necessary. Will finish jig tonight and start test fitting things tomorrow. Thanks for letting me butt in on this thread.

It's a little confusing to me as well! I would also think the opposite. Only thing to keep in mind is that Toyota suggests a MAXIMUM of 3 thin shims - so don't go crazy with the sander!

I really should build a Jig. I had one set up with some scrap wood I had laying down, but it couldn't stand up to the torque I was applying when tightening the pinion nut. Hence the previously depicted "long metal bar" method.

Don't worry about butting in! If you get a chance, post up some pictures. I'm happy anytime my threads can help others learn along with me!

 

[Pin_Head]

You need one preload washer and the minimum is 2.75mm. It would take 10-12 thin shims to make up this thickness. Take a closer look and see if yours isn't still stuck on your pinion. I have a couple of washers in my junk drawer if you get stuck and need one.

Rick:
I don't know about gentleman, but I am indeed a scholar. I trained in East Baltimore.

 

[srgould41]

I wonder if Peel Shims would work, or would they be too soft?

 

[RWBeringer4x4]

I have a couple of washers in my junk drawer if you get stuck and need one.

Rick:
I don't know about gentleman, but I am indeed a scholar. I trained in East Baltimore.

Depending on how badly I mangle this washer, I may need one of your spares! East Baltimore? Right down the street (I-95) from me! My Fiance works in the Inner Harbor.

I wonder if Peel Shims would work, or would they be too soft?

I'm not sure - I'm mostly curious about the "bevel" in the factory washer. If that is, indeed, important, than it would prevent someone from using "just any old washer." That said, I can't figure out why that bevel would be important. From what I can tell, both surfaces sandwiching the washer are flat...

 

[Pin_Head]

I will save a washer for you. The Inner Harbor is sure nice now, but it was a dive back then. I worked at Monument and N. Wolfe St. You din't want to hang around there after dark. I still have fond memories of the fresh oysters and soft shell crab sandwiches with Utz potato chips washed down with a Natty Boh at the Northeast market.