It's kinda long but stick with me.

Here is my problem my pinion flange nut is stamped so it can not loosen on its own but some how the pinion flage gets vertical slop(which also ads to rotational slop, but there is suposed to be a little of that), and i am sure it is the whole pinion and flange assembly that moves, it is not wable between the flange and the pinion on the splines. If i tighten the nut it goes away, but it keeps coming back.:mad:

This is an stock LC diff from a 70 ish land cruiser, and the diff is welded. In these difs there are no crush sleves.

Between me and a buddy we have wrecked two diffs from this. His got loose and retightened about 5 times then one day on the freeway his ring gear spun the bolts on the carier. On my old diff this hapened and i tightend it with an impact gun to make sure that it would not happen again like my friends, but that was a mistake because i overtightened it and seized the pinion bearing, end of diff. oops. All of these diffs were old LC stuff and were welded.
Also when i tighten the nut to the stock torque spec of like 175(i can't remember exactly off hand) it makes the pinion spin jerky, like the gears are not meshing correctly.

So here are my questions,

When you tighten the pinion nut does that change the mesh patern, causing the gears to eat themselves like my friends diff did???

Should i just keep retightening it and see what happens, or should i leave it and see what hapens?

I am almost shure this is caused by pinion bearing wear, but the diff does not howl or anything. This only has to last me one season, so i do not want to spend any money, and i am running out of diffs in the parts pile, and all of them seem to do the same thing, this one after one run.

Thanks

Ian-

If the nut is still staked, but you have no pinion preload and there is sideways slop, then chances are that your preload shims have spun, most likely due to the outer pinion bearing failing. You need a new bearing, but changing the bearings is maybe more difficult than welding up another 3rd member. If you have to set the preload by trial and error it will take more time. If the old shims were good at least you know you will be close. If you decide to replace the bad bearing get the entire set of preload shims from Toyota and return the ones you don't use.

Originally posted by Pin Head
If the nut is still staked, but you have no pinion preload and there is sideways slop, then chances are that your preload shims have spun, most likely due to the outer pinion bearing failing. You need a new bearing, but changing the bearings is maybe more difficult than welding up another 3rd member. If you have to set the preload by trial and error it will take more time. If the old shims were good at least you know you will be close. If you decide to replace the bad bearing get the entire set of preload shims from Toyota and return the ones you don't use.

The nut is still staked. The slop is minor but with past experience i know it can get worse. Other than the slop there is no reason to say that the outer bearing is bad, and there is no notion that it is. I checked my old diff, the one where i over tightend the pinion nut and screwed up the bearing and pinion and flange, the spacers still seem to be in good shape. Although i am not shure what the spacers are, if you are refering to the little thin circles that sit on the pinion where the spline ends, and there is a step up in the pinion, than those are ok.

It sounds to me like what you are saying it to re set up the ring and pinion, but before i go that far i would like to know what is causing it , and why is it bad to just tighten up the nut if the spacers are in good condition. and not only the spacers but the bearing. I know the bearing is old but there is no reason for it to be bad.
Thanks Pin Head, got any more ideas, have you run into this same problem.

Ian-

Ian

I think what is happening is the shims between the pinion flange and the outer bearing are ,spinning or they got crushed a little from the load, hence the slight amout of looseness. Once this starts if you don't get after it, eventually it will fail and toast the bearing. You really should get a backlash reading just in case, then pull the flange , the pinion shims and the outer bearing and inspect them. I would not be surprised to hear some of the thinner shims are getting crushed, I also wouldn't replace the outer bearing unless it should signs of pitting, gouging, accelerated wear. I would beg, borrow or steal a factory manual on the diff and then read it.

And yes I have ran into this problem, I was crushing the smaller shims in the stack of shims with the pinion flange. I ended up replacing the crushed smaller shims, and moving them to the center of the pack and that cured it.

Also another thing, the amount of shims to get the correct preload and pinion depth on one set of gears in a particular housing is just a starting point in another housing with the same set of gears. The outer shims set the preload on the bearings and the inner shims, can't remember if there under the bearing race or behind the bearing, set the pinion depth. After these to goodies are right, then it's a simple matter to set the backlash and differential side bearing preload and read the pattern to ensure your golden.

Good luck Keith

Ian,
PinHead and Krcruiser are right. You've got wear in either the bearing preload shims, the pinion depth shims, the bearings themselves or most likely all of the above. Also check the end of the pinion flange itself and the washer that sits behind it. If you've been torquing it down then these can get damaged or worn too. I had the same happen to my rear diff years ago. It did all of the symptoms you describe and everything looked to be in OK shape. If you just keep tightening the pinion flange without addressing the bearing preload shims and outer bearing it will keep coming back and you will permanently damage the bearings.
Check this out from Specters diff page -
" If you were just to tighten the nut, improper Brg #20 to Brg #27 pre-load will occur and cause bearing failure. Check #27 Bearing for scoring on race & rollers. Also check #26 shims for spinning. Replace parts as needed. Always replace #29 Pinion Seal on replacement of any parts. Torque spec on #33 nut is 160 ft/lbs."
Sphincter's diff page (http://www.sor.com/sor/cat090.tam?xax=19809&page%2Ectx=cat090%2Etam)

Time to swap diffs with one of your spares and then spend some quality time learning how to set up gears

Originally posted by COMPLAINE

The nut is still staked. The slop is minor but with past experience i know it can get worse. Other than the slop there is no reason to say that the outer bearing is bad, and there is no notion that it is. -

Take the flange off, pull the seal and outer pinion bearing and take a peek. If the bearing and race are OK, then just reset the pinion preload using new shims and preload spacer. The thin metal shims are to compensate for different thickness of pinion depth washer (the one betwen the inner pinion bearing and the pinion gear). You use the same number of these shims. The preload washer is thicker and comes in about 12 different sizes. Get all 12, find the one that is right and return the rest. It is difficult (if not impossible) to over torque it when the shims are correct, unlike diffs with a crush sleeve. If the shims have spun and worn down, torquing it will give you too much preload and the bearings will fail quickly.

If the pinion bearing is bad, then pull the 3rd member, mark the positions of the adjuster nuts on the carrier side bearings, replace both pinion bearings (reusing your original depth washer) and reset the pinion preload as above. Put the carrier back in with the adjuster nuts in the same positions, check tooth contact pattern and backlash and you are good to go. I have had good luck getting the tooth contact and backlash correct just reusing the depth washer and using the original adjuster positions, but it is always good to check.

Ok guys were doing good so far, but i havn't quite grasped this one yet.

I took apart a POS diff i have to see what i will be looking for in terms of spacers. Because i am sure that my bearings will be fine.

In my head i had a picture from taking apart a previos diff and seeing little flaky washers on the pinion, so that is all that i thout was there but you guys talked of two differnt kinds so i took a look.

Ok what i found in this diff is 2 spacers on the pinion that both slide over the splines and ride between the step in the pinion and the bearing. One is thick and one is really thin.
So from what i have gathered the thin one is a spacer for the difference between different housings, and the thick one is the pinion depth spacer.
And i am supposed to figure out if either is worn wich i will assume that both are worn because that is the case in all other difs i have taken apart.
Krcruiser mentioned a spacer behing the race, but if the race has not spun i don't know how it would wear.

So if there are 12 different spacers, how do i find out wich one i need once it is all apart?

Do i basicly have to set up the whole ring and pinion, because i have not trusted myself in the past to do it so why do it now?

I don't have a dial guage to take any measurments, and don;t have access to one. So what do i realy need to do before i start, and after i am done, and figuring out what spacers to use.(i mean tools, gear paint etc.)

Am i looking at the wrong things? If i am not i am going to assume the bearings are good and the spacer is worn so that is the point were i now need direction.

Thanks.

Ian

Originally posted by COMPLAINE
Ok what i found in this diff is 2 spacers on the pinion that both slide over the splines and ride between the step in the pinion and the bearing. One is thick and one is really thin.
So from what i have gathered the thin one is a spacer for the difference between different housings, and the thick one is the pinion depth spacer.

Nope. The thin one is to compensate for the thickness of the pinion depth spacer. The thick one is so set the preload. The pinion depth spacer is between the inner bearing and the pinion gear.

Originally posted by COMPLAINE
And i am supposed to figure out if either is worn wich i will assume that both are worn because that is the case in all other difs i have taken apart.


If they have spun, they will look scored and fawked up. It is not a bad idea to replace both of them, since you have to reset the preload anyway. Remember, if you have no preload somehting bad has happened to either your bearings or any of these shims.

Originally posted by COMPLAINE

So if there are 12 different spacers, how do i find out wich one i need once it is all apart?



Trial and error.

Originally posted by COMPLAINE
Do i basicly have to set up the whole ring and pinion, because i have not trusted myself in the past to do it so why do it now?


No. You only have to set the pinion preload. Even if you have to change pinion bearings, this isn't going to change your pinion depth or tooth contact in my experience.

Originally posted by COMPLAINE
I don't have a dial guage to take any measurments, and don;t have access to one. So what do i realy need to do before i start, and after i am done, and figuring out what spacers to use.(i mean tools, gear paint etc.)

Am i looking at the wrong things? If i am not i am going to assume the bearings are good and the spacer is worn so that is the point were i now need direction.

Thanks.

Ian

You can get a dial indicator and magnetic base for less than $20 at Harbor freight. If you mark the position of the side bearing adjuster nuts, you can get them back exactly the way they were, so the backlash and carrier preload should be the same. It is a good idea to check.

If your outer bearing and shims are fine, they you should look at the inner bearing and depth shim. They don't just loose preload for no reason if the nut is still staked.

Ok i had to take a break for a day and do some school work.

Lets see if i got it right this time.'

The pinion depth spacer is the one that is behind the inner bearing wich is pressed onto the pinion. It is sandwiched between the gear and the bearing.
And a second assumpion i am going to make is sence that bearing is pressed on if that is the correct spacer i am looking at the bearing would have to spin on the pinion which it is not supposed to, and that really would be the only way to wear that shim.

The pinion preload spacer and acociated washer thin thingy, have wear on all my other difs, and since they are easy and simple to replace(no guessing or removal of carier) if they show wear should i just replace them??
I say that because if i am looking at the right parts it looks verrrrrryyyyy hard to wear the pinion depth shim.

Thanks again for your help i think i almost have it figured out, at least until it comes time to actually doing the job.

Ian-