87_LG4

Hi,

I am in the process of installing a Truetrac in my 10-bolt. I have gotten as far as pattern check, but this is my first time and I am not versed in the subtleties of gear and pinion patterns. Can anyone tell me if I'm in the ball park?

I do not have very good reception where I am at the moment, so I cannot upload the pictures again. I'll just link to my original thread:

Post #29 - Pattern check pictures

If you need I can get more pictures tomorrow.

Thank you.

big gear head

Is this a new gear? Did you turn it with the pinion or did you put an axle in and use that to turn it? You will get a more clear pattern if you use an axle to turn it. Some of the teeth look like they are very close, but some look like the pinion is a little too deep. I'd like to see more pictures after you turn it several times in both directions with an axle.

87_LG4

Brand new gear and all. The pictures you see are from turning the pinion. I will get right to it turning with an axle. Thank you for the quick reply

87_LG4

Turned the gears using the axle like you said. Seems now it is a bit far out on the heel on the drive side, and a bit towards the toe on the coast side. Might also be a bit towards the root on both.

What do you think?

87_LG4

Derceased the pinion shim and moved the carrier about a hairswidth towards the passenger side. Backlash measured to 0.007". Came back with this:







Seems a bit toward the heel on the drive side? And a little toward the toe on the coast side?

On an unrelated note, am I the only one getting a bunch of random text on this site turning into hyperlinks directing to ads saying [Click to Continue > by DiscountLocator] ?

big gear head

In post number 4 the pinion is a little too deep. How much did you change the pinion shim for the pictures in post number 5?

87_LG4

Pinion depth is the same for picture 4, 5 and 6. Between pictures 3 ad 4 I went from 0,9mm to 0,8mm. Or from ~0.035" to ~0.032", according to good old Google.

So you think I should increase the pinion back to 0.9mm?

big gear head

No, I think you should keep going in the same direction a little more. Try a slightly thinner shim, about .030 inch, and see if it brings the coast and drive patterns closer together. Right now you have a drive pattern that favors the heel and a coast pattern that favors the toe. See if the thinner shim will bring them both closer to the center of the tooth. Keep the backlash within the recommended specs.

87_LG4

I'll try that as soon as I get home from work. I just hope I have shims that will allow me to make 0.002" increments. I gotta say, I was less than impressed with the selection that came with the Yukon master overhaul kit.

87_LG4

Decided that carrier preload was just a tad too much, so went down an equal modicum on both sides. Tried shimming the pinion to 0.7mm, but that was way off, so went back to 0.8mm. Now I've got this:







Seems to be a hint towards the heel on the drive side, and a nudge towards the toe on coast. Face/root seems good to me, but I'm no expert. So where should I go from here? Hoping for a quick reply, so I can keep going before it gets dark here.

Thank you

EDIT: Forgot to mention, backlash is 0.009".

87_LG4

Moved the carrier ever so slightly towards the passenger side. Backlash decreased to 0.008" and the pattern now looks like this:







Should I keep hunting?

big gear head

I would try the pinion shim and see what happens. I think a very slight pinion shim change will even everything out. Backlash isn't going to make it any better right now.

87_LG4

Because it was getting late here I tried to change the backlash to and from a little bit. Managed to bollocks it up, tried every combination that I had written down, could not get it back to where it was last post. Started changing the pinion shim to see if that might help. After a bunch of tries we got as far as this:







Now what? Is it good? Good enough? If not, what should I change?

Backlash is 0.009"
Can't remember the shim sizes at the top of my head. It's getting late

big gear head

It might be fine like it is. If you don't have the correct shim selection to take about .002 more out of the pinion shim then I'd run it like this. Be sure to check the backlash specs in your instructions. Yukon gears usually run a little more loose than other brands. If the pattern looks best tighter then run it tighter.

87_LG4

Couldn't find a shim combo that gave me .002 less, so I decided to run it like it is. For all the praise Yukon gets on this site for their products, the instructions that came with were lacking at times. They had several references throughout the booklet telling me to see page 11 for backlash specifications, but after having looked through the entire thing front to back I could not find any specs on that, page 11 or otherwise. Peculiar...

But, now it is assembled, and all I need to do is mask and paint it, fill it with oil and put it back on the car. Can't wait!