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Ring & Pinion Advice

I need to know where the pinion depth shim is installed on 12 bolt, so I am not guessing. No patience for Utube dweebs this evening. Is between the pinion gear and the inner bearing ? or is it behind the inner race cup in the housing ? I still say .242" not right. my mind says more like .024" is the .242 possibly a typo ?
 
On the rear I simply used the original shim and put on the original bearing ground to be a set up bearing. I installed it without the crush sleeve and torqued to the preload spec.

I put the carrier in with the new bearings and the original shims.

Backlash was way off so I used a shim pack and got the backlash to 7 thousandths. Tried running a pattern and the theeth never would mark the yellow paint. At least not enough to show a pattern. So, late last year I put baby in the corner and yesterday I called my uncle for advice/assistance.

And here we are…
 
texarback said:
On the rear I simply used the original shim and put on the original bearing ground to be a set up bearing. I installed it without the crush sleeve and torqued to the preload spec.
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This to me says the shim is between the bearing and the pinion gear head. That shim is how thick ? .242" ?
 
Wes Harden said:
I need to know where the pinion depth shim is installed on 12 bolt, so I am not guessing. No patience for Utube dweebs this evening. Is between the pinion gear and the inner bearing ? or is it behind the inner race cup in the housing ? I still say .242" not right. my mind says more like .024" is the .242 possibly a typo ?
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Definitely a typo. Sorry. I was multitasking when I wrote it.

The shim goes between the head and the bearing.

IMG_7705.jpeg
 
ok that is much better am glad was just a typo.

For the marking issue, I find that having some heavy resistance to turning the ring gear help get a nice pattern to show.

Now the carrier bearings have no shims between the bearing and the carrier ?
 
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Wow so nice and clean, who's your parts washer :waytogo:. I don't see anything obvious in those photos.
Another tip on marking a little tiny bit of gear oil mixed in the marking compound can help. If you have a helper have them turn the pinion and you hold a ring gear bolt with a box end wrench. you can have the helper turn the pinion both ways a few times while at the marking compound.
 
Correct, on the rear there are no shims between the carrier and the bearing.

I scrubbed. The inside of both diffs were pretty rusty. The truck sat for years and it had that natural rust line. Lots of elbow grease and WD40.

The amount of grease and mud took forever to get off.

Here is the before and after on the front.


IMG_6874.jpegIMG_7675.jpeg
 
I called Houston Drive Train this morning to get their opinion. They said "absolutely" replace the ring and pinion if I'm changing the bearings, shims, etc. He said almost verbatim the same thing my uncle said.

So, looks like I have my answer. I'll update my build thread once I get R&Ps ordered and the diffs put back together.

Thanks for the back and forth on the topic.
 
Next question...

If I were going to change ratio, what would be the advice? I know nothing about it other than what I've read.
 
Tire size you plan to run?

Transmission?

Driving type you plan to do?
 
Well, the question is moo (you know, like a cows thought) now. I went back with the 3.07 ratio. First, I've ordered all my front end Dana parts from Denny's Driveshafts. I talked to him today and he recommended just going back with what I have. He is a great guy. Yukon recommended staying with the 3.07 too. My Uncle also recommended staying with the 3.07.

3 for 3 can't be wrong, right?

I'm running a normal tire on original rims with the 3 speed automatic. I'll only be street driving and occasionally may take it on the highway. Mostly going to and from grocery and restaurants. Maybe a Sunday cruise on the old state highway system.

I went with [706017-1X] Dana Spicer 706017-1X Ring and Pinion Gear Set Kit 3.07 Ratio (43-14) for Dana 44 and Yukon [YG GM12T-308] High performance ring & pinion gear set for GM 12T in a 3.07 ratio for the rear.
 
I probably would have went to 3.73s just to gain a little more grunt and because I was spending the money anyway, but for your uses I see no problem with 3.07s.
 
Chickntrk said:
I probably would have went to 3.73s just to gain a little more grunt and because I was spending the money anyway, but for your uses I see no problem with 3.07s.
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That was the general consensus from everyone. I am finding that the right answer is very elusive.
 
The correct answer for best ratio will be different for ea owner and ea truck. Your driving needs, weight of truck, tire size, transmission gear ratios, and engine power band. Since you are restoring this K5 to original and not up sizing tires, or changing the engine power band rpm, the 3.07 will be fine. Once you open modification Pandora's box, it seem no good mod goes with out another
 
Ok. I’ve been learned some things today.

Anytime you change bearings, races, and shims in a diff; change the ring a pinion.

The results after putting the new R&P is amazing.

This is the rear…

1) Using same thickness pinion shims (0.027). Above I said it was 0.0245. Remeasuring in multiple spots gives 0.0270.

2) Using the original carrier shims (0.0380 pinion side) and (0.0420) gives me a 7 thousands backlash.

3) pinion preload is around 20. Yukon says 13-15 so I’ll get that better on final assembly.

Here is the pattern on try #1:

IMG_7717.jpeg
IMG_7716.jpeg
IMG_7715.jpeg
IMG_7714.jpeg

Thoughts, suggestions, at-a-boy?
 
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I’m thinking the pinion is too close.

IMG_7718.jpeg

I’m shocked at how I can now get a pattern. I never would have thought changing the R&P would make that type of difference.
 
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