Front Diff Gear Pattern - Again.

[Gerrha]

I know this has been gone over many times. The problem is, after you have looked at a pattern 100x, you begin to see whatever you want in them. A different set of eyes surely can help out.

My two patterns are shown below. From what I see in the guides, my photos would indicate a slight decrease in pinion depth is warranted. But I have looked at multiple Zuk setups, and he seems to favor a slightly deep pinion. These are new Nitro 4.56 gears with WPC treatment, and the pinion spacer is 0.0740" thickness.

Thanks for the look and opinion.

 

[matzell]

First that is a lot of comound on there. From what I can see it does not look too bad. Try to hold some resistance on the ring gear when you spin it to allow more contact with the teeth to make a cleaner comound.

 

[Gerrha]

Yeah, that is a lot of compound. That stuff gets everywhere. I was putting a lot of resistance and using a drill on low speed to rotate the pinion. The backlash was 0.006"

 

[Gerrha]

Here are a few more photos.

 

[Kernal]

I forget, did you get this link (ZUK)?? His email is on the web site, send him a photo?

FWIW

Toyota Gear Install

ZUK shares many close-up good pics of Toyota gear installs

gearinstalls.com

 

[Gerrha]

I read 7-8 of Zuk's writeups but I did not contact him directly. I sort of thought he was retired from this work and did not want to bother him.

I just rechecked the ring gear backlash and it is now at 0.004". It was 0.006" so I am not sure what happened there, but it looks like I get to start over.

 

[matzell]

Check it in 2-3 places. Take the average.

 

[JoeCova]

I’ll see if I can find pics of my 3rd members. Here’s a 14bt in the interim.

Found it.

 

[Gerrha]

Thanks. I just did that and got range from 0.004" - 0.007" and I noticed that Zuk measures in 20 places and takes the average. On Zuk example I am looking at right now, the low is 0.005" and the high is 0.008".

 

[Gerrha]

I’ll see if I can find pics of my 3rd members. Here’s a 14bt in the interim.


View attachment 4025532View attachment 4025533

You show sort of clear dark patterns, and I don't have that in mine. Is that because I put way too much compound on there?

 

[JoeCova]

You show sort of clear dark patterns, and I don't have that in mine. Is that because I put way too much compound on there?

Maybe, or I have more resistance. I just mix the paint with some gear oil and then brush it on lightly. Thin enough to just cover the tooth.

I crank the pinion by hand while using a rag to hold the ring and provide additional resistance.

 

[vipergrhd]

Did you check your pinion preload before and after you installed the carrier? I too check pattern about 4 spots on the ring gear, and I would start over and clean the excess compound. .005-.008 is good to me I just don't know what the specs. are.

 

[Gerrha]

Did you check your pinion preload before and after you installed the carrier? I too check pattern about 4 spots on the ring gear, and I would start over and clean the excess compound. .005-.008 is good to me I just don't know what the specs. are.

The backlash spec is 0.0051" - 0.0071". I did check the pinion preload before and after carrier installation. Now, I did notice that the preload was more or less the same after installing the carrier. The FSM states that the preload should increase by 3.5 to 5.2 in-lbf above the initial preload. Again, I am not sure what happened there.

 

[vipergrhd]

The backlash spec is 0.0051" - 0.0071". I did check the pinion preload before and after carrier installation. Now, I did notice that the preload was more or less the same after installing the carrier. The FSM states that the preload should increase by 3.5 to 5.2 in-lbf above the initial preload. Again, I am not sure what happened there.

Did you already do a final torque on your pinion and carrier? Check the runout on your carrier if there is room on the backside.

 

[Gerrha]

Not yet. I am still in the initial stages of the job. I won't move forward until I am totally happy with what is going on. That, plus I am waiting for a Marlin Crawler solid pinion spacer.

 

[Gerrha]

Did you already do a final torque on your pinion and carrier? Check the runout on your carrier if there is room on the backside.

The runout is virtually impossible, I think. There is no lip on the ring gear to set up the measurement.

 

[JoeCova]

The backlash spec is 0.0051" - 0.0071". I did check the pinion preload before and after carrier installation. Now, I did notice that the preload was more or less the same after installing the carrier. The FSM states that the preload should increase by 3.5 to 5.2 in-lbf above the initial preload. Again, I am not sure what happened there.

Moot, it’s a reference check the key thing is understanding your final preload.

 

[Augustiron]

I'm happy to do most work on my cars...

But Ring and pinion setup is right up there with an automatic transmission rebuild for things that a Visa card fixes for me

 

[Malleus]

I know this has been gone over many times. The problem is, after you have looked at a pattern 100x, you begin to see whatever you want in them. A different set of eyes surely can help out.

My two patterns are shown below. From what I see in the guides, my photos would indicate a slight decrease in pinion depth is warranted. But I have looked at multiple Zuk setups, and he seems to favor a slightly deep pinion. These are new Nitro 4.56 gears with WPC treatment, and the pinion spacer is 0.0740" thickness.

Thanks for the look and opinion.



View attachment 4025497View attachment 4025498

FWIW, I used to do this for a living, on a production axle assembly line. I'd send that pattern without a second thought.

A thought on printing for setup: use an old toothbrush and paint 4-5 teeth, both sides, 120° apart in three places. Don't put any more paint on the brush once you dip it initially. You can go over a tooth again if need be, but too much compund can mask fit problems. You want it thin enough that it doesn't take up room, but thick enough that it can be seen.

Two (general) things:
1» A pattern will never get any farther out; you can always move it in but never out. Gear teeth wear in; once they wear, you have to move deeper to get contact.
2» You should be able to turn the gearset by hand; if you have to use a drill, it's too tight. This is from experience building very large gearsets. Our hand crank was mounted directly on the pinion (we adapted it from a large Cincinnati mill we blew up).

 

[vipergrhd]

Just out curiosity, where do you apply the final preload on the carrier bearings? Ring side or Carrier side? It could add or decrease your backlash reason I asked but that also depends on the procedure. I apply the final preload once I get all my readings where I wanted, I don't finish off the pinion preload if I'm using crush sleeve but on a solid spacer I just get my preload and final torque all at once.