Need gear pattern feedback

[MtBraun]

Setting up my first diff, front D44 on this build. First pattern, (not pictured) showed contact angled across the root and coast side was centered. I removed pinion depth shims because that pattern suggested pinion was too deep. Now I am having a really hard time making a drive side pattern. It is very faint despite putting all the resistance I can with one hand while turning with the other. You can see in the pic how the marking compound is “peeling” towards the valley in the drive side gear. The last tooth though appears to be high, which suggests I may need to add pinion depth shim.

Backlash is a little high at .009 but within spec.

I am reusing gears and am confident it wasn’t set up correctly to begin with, so is it possible incorrect gear wear is affecting the pattern? I would appreciate the experienced and critical eye. Thanks.

 

[nvrenuf]

Imo, it’s too faint to read well. I’d suggest rerunning the pattern but apply a fair amount of resistance to the ring gear while turning so it imprints better.

 

[MtBraun]

Imo, it’s too faint to read well. I’d suggest rerunning the pattern but apply a fair amount of resistance to the ring gear while turning so it imprints better.

Any suggestions on resistance? I'm turning with the yoke holder and using my other hand with a glove to provide resistance against the ring. Holding as tight as I can. Seems like it should be enough resistance based off what I've seen others do.

 

[nvrenuf]

I’ve helped a friend a few times and he will have me apply a lot of pressure to the ring (glove, shop rag in hand, etc) while he turns the pinion. With 2 people you are free to put more pressure on it, make sure the paint is wet too.

 

[CalSgt]

I tap a chisel between the ring gear (or edge of carrier) and diff housing then move it to the opposite side to pattern the other direction. The ring gear pulls the chisel in tighter as you rotate the yoke, rotating back the other way while pulling the chisel lets it free.

I’ve seen people use a wooden hammer handle and other things to lever against the assembly too.

I’ve also had better results by thinning the pattern paint down by stirring in a few drops of oil or atf.

ETA: You need to have enough resistance to wipe the pattern paint clean in the center of the contact patch. The edges of the pattern won’t show otherwise, the edges should feather out gradually and not have a sharp abrupt line.

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[bucket]

Keep in mind, the front axle spends most of it's time running with pressure on the coast side.

 

[MtBraun]

Keep in mind, the front axle spends most of it's time running with pressure on the coast side.

With that in mind, how does the coast pattern look? I think it’s pretty close.

 

[MtBraun]

I was able to get more resistance and a better pattern. High on the drive side, good on the coast side. I think pinion need to come in deeper against the ring gear (add pinion shims). Thoughts?

 

[CalSgt]

How’s your backlash?

Moving the pinion towards the ring gear will probably tighten the backlash a little.

If backlash is on the tight end of the spec you may need to move the carrier towards the ring gear a bit when you move the pinion.

 

[MtBraun]

How’s your backlash?

Moving the pinion towards the ring gear will probably tighten the backlash a little.

If backlash is on the tight end of the spec you may need to move the carrier towards the ring gear a bit when you move the pinion.

Backlash was at .009. I ended up adding a .005 pinion shim and it patterned well. That did decrease backlash to .006 but since it was still in spec left it alone.

Overall I had a lot of fun with this. I used the SIU video on Youtube. It's a fantastic resource and you really can't screw this up based on that video.