Gear wear pattern (not GM) - Chevelle Tech
Transmission & Driveline Transmissions and Differentials

 
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post #1 of 9 (permalink) Old Apr 17th, 15, 10:40 PM Thread Starter
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Gear wear pattern (not GM)

I hope I don't offend anybody posting a question about a non-Chevelle rear.

My brother replaced the bearings in a Ram dualie rear, with well over 200k miles on it. I thought I'd see if the experts have an opinion about the looks of the pattern. It has the original gears and pinion shim. Doesn't have carrier shims -- it has a screw-in adjuster on each side. The rear is kind of like a non-removable Ford third-member, the way I see it.

Thanks for any opinions.
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post #2 of 9 (permalink) Old Apr 17th, 15, 10:44 PM
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Re: Gear wear pattern (not GM)

What's the backlash at there? Did you turn the pinion or the ring gear to get the pattern?

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post #3 of 9 (permalink) Old Apr 17th, 15, 10:53 PM Thread Starter
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Re: Gear wear pattern (not GM)

The backlash is at .005 and the book says .005 to .007 (for an 11.5 inch Dodge rear). Unfortunately he didn't check the backlash before he pulled it apart. (He didn't ask me ahead of time :-) He got the pattern by turning the pinion with a drag on the ring gear through the e-brake.
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post #4 of 9 (permalink) Old Apr 17th, 15, 10:55 PM
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Re: Gear wear pattern (not GM)

Probably pretty good for a gear with that many miles on it. You might need to make a slight pinion depth adjustment. The coast pattern looks like it's centered pretty we'll between the root and face. It's heavy on the toe side, but you might be able to adjust the backlash a little and help that. What is the backlash right now?

Is that a Truetrac differential?


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post #5 of 9 (permalink) Old Apr 17th, 15, 11:33 PM Thread Starter
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Re: Gear wear pattern (not GM)

Thanks for the insights.

He's got about .005 backlash. I asked whether he measured at 3 places and he said he did, and it varied up to about .006 backlash. But he also said he was having a tough time getting the dial indicator itself to stay steady.

I don't know if it's a truetrac but I can ask him. I can tell you I helped him pull the carrier out last weekend and it was a true back breaker :-)

Are you thinking increase the backlash a hair?

What might he do with the pinion depth? To my untrained eye I couldn't tell.
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post #6 of 9 (permalink) Old Apr 18th, 15, 1:28 AM
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Re: Gear wear pattern (not GM)

This looks like the newer style 2 step gear. These gears have a biased pattern when new, and I haven't had enough experience with them to read the patterns very well. I would check the service manual and see what the backlash is suppose to be set at and then add about .001 to .002 to that. The newer gears run much less backlash than the older 5 step gears. Try it with the pinion depth like it is and see if it runs quiet.


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post #7 of 9 (permalink) Old Apr 18th, 15, 9:56 AM Thread Starter
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Re: Gear wear pattern (not GM)

Thanks Freddie.

I believe it's an '11 model truck and the manual says .005 to .007 backlash. I was thinking he ought to at least be on the loose end of that range given the mileage, and going beyond it makes sense to me given the high mileage. It's a work truck, and it's been worked and now rebuilt hopefully go another 200k+ miles.

Thanks again.
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post #8 of 9 (permalink) Old May 3rd, 15, 11:15 AM Thread Starter
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Re: Gear wear pattern (not GM)

Freddie,

My brother opened up the backlash as you suggested and got a nice pattern -- I was amazed how much it improved -- and reports that it's back on the road with no noise. So thanks again. You are a treasure.

He's now working on a Mopar 9 1/4, posi 3.90:1. Another in a fleet of a family member's work trucks. I had him check the backlash and take pictures of the "before" wear pattern, so that he'll know what the "after" should look like. Are you still in business and selling parts? Doing rebuilds? He's looking to get info. on parts or a rebuilt unit.

Thanks
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post #9 of 9 (permalink) Old May 3rd, 15, 3:50 PM
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Re: Gear wear pattern (not GM)

I'm glad it worked out well for him. I closed my business in 2012. I still do some rear ends from time to time, but not like I did before. I stopped doing them under the car and now I make people remove the rear end and bring it to me, or take it somewhere else.

If he does what you told him to do then it should be a lot easier this time.


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