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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Rear Drivelines, Drive Axles and Gearing => Topic started by: Ronno6 on September 14, 2018, 10:45:34 AM

Title: Ring Gear Backlash
Post by: Ronno6 on September 14, 2018, 10:45:34 AM
I have seen this mentioned on older threads, but, rather than resurrect an old thread, I'll just ask:
1984 C-10 8.5" 10 bolt diff 3.73 ratio
I nave seen ring gear backlash specs listed as .003" - .006" from some sources, and  .006" - .010" from others (more prevalent,)
What is the wisdom of the crowd??
Thanks.
Title: Re: Ring Gear Backlash
Post by: Henry on September 14, 2018, 11:31:03 AM
Hi Ronno6:
My 1976 Overhaul Manual has .005-.008 inch for the differential you mentioned...I do not believe the gear ratio has anything to do with the backlash. You should look at the 1984 Overhaul Manual to see if the spec changed...the manual should be on the tech section of this forum or on the net somewhere.
Regards,
Henry
Title: Re: Ring Gear Backlash
Post by: Ronno6 on September 14, 2018, 11:57:50 AM
Regarding Henry.....good flick.

Thanks for the guidance.
Title: Re: Ring Gear Backlash
Post by: Ronno6 on September 14, 2018, 02:37:32 PM
OK. Initial backlash measures .012"
I need to move the ring gear .006" closer to the pinion to achieve a good amount of backlash.

A side note: I had to reduce the thickness of the original left side shim by .003 to install.
Is this common, or should the original shim packs always be installable with a new carrier?

Can I check the engagement pattern at this time?
Or, will that change appreciably when I move the ring gear in ?

That is to say, if the contact patches are good now, will they change when I shim the ring gear?
Title: Re: Ring Gear Backlash
Post by: VileZambonie on September 14, 2018, 03:49:59 PM
You have to rob Peter to pay Paul. If you are removing thickness, you are reducing bearing preload.
Title: Re: Ring Gear Backlash
Post by: Ronno6 on September 14, 2018, 04:39:17 PM
You have to rob Peter to pay Paul. If you are removing thickness, you are reducing bearing preload.

I understand that.
Question is, I suppose, could ther be a difference between the OEM open carrier and the Yukon Posi carrier??
If the two are exactly the same, then I should put the original left side shim back in.................

When I disassembled the diff I had to pry the carrier out of the housing.
Should that be necessary? Should it be that tight?
Title: Re: Ring Gear Backlash
Post by: VileZambonie on September 15, 2018, 08:17:21 PM
Yes, it should. Are you measuring side clearance?
Title: Re: Ring Gear Backlash
Post by: Ronno6 on September 15, 2018, 10:19:10 PM
Yes, it should. Are you measuring side clearance?

Not as of yet. I could use an education,please.
Title: Re: Ring Gear Backlash
Post by: VileZambonie on September 16, 2018, 12:56:38 PM
There are plenty of posts on the forum in regards to this subject. Keywords, pinion depth, backlash, gear tooth contact pattern should all yield some good results.



Title: Re: Ring Gear Backlash
Post by: Ronno6 on September 16, 2018, 03:50:10 PM
There are plenty of posts on the forum in regards to this subject. Keywords, pinion depth, backlash, gear tooth contact pattern should all yield some good results.

That is true.
But, The only posts I can find that mention side clearance are the one you sent me and I replied to..a couple of posts ago.

I have achieved a backlash of .006" - .009" and a very good contact patch.
Now to disassemble to install the crush sleeve, set pinion preload, then reassemble and re-check.
Title: Re: Ring Gear Backlash
Post by: VileZambonie on September 16, 2018, 06:13:21 PM
Side to side = carrier bearing preload. So if it's good then you will have good long term results.
Title: Re: Ring Gear Backlash
Post by: Ronno6 on September 16, 2018, 06:17:29 PM
Side to side = carrier bearing preload. So if it's good then you will have good long term results.

There be no measurable side to side play....I have to tap the shims in, and have to pry the carrier out....
Hopefully
i am headed in the fight direction.
Thanks!
Title: Re: Ring Gear Backlash
Post by: VileZambonie on September 16, 2018, 06:31:27 PM
You measure it by affixing a dial indicator to the side of the ring gear. Pry the carrier from left to right and right to left. The recorded measurement on the dial indicator is your side clearance. You will have to force it in and out unless you have a housing spreader.
Title: Re: Ring Gear Backlash
Post by: Ronno6 on September 16, 2018, 06:58:38 PM
You measure it by affixing a dial indicator to the side of the ring gear. Pry the carrier from left to right and right to left. The recorded measurement on the dial indicator is your side clearance. You will have to force it in and out unless you have a housing spreader.

Gotcha.Thanks.
I'll check.
Bearing caps loose or tight??
Title: Re: Ring Gear Backlash
Post by: VileZambonie on September 17, 2018, 04:08:06 AM
You measure with it properly installed and caps torqued to spec.
Title: Re: Ring Gear Backlash
Post by: Ronno6 on September 18, 2018, 09:21:41 AM
You measure with it properly installed and caps torqued to spec.

I am ot able to measure any side play,
I do however measure 003" of lateral runout on the back side of the carrier flange.
I measured the same runout on the back side of the mounted ring gear.
Is that normal/acceptable??
Backlash is measuring ar min .006" max .009" with most readings being .007" - .008"

Contact patch is excellent.
Title: Re: Ring Gear Backlash
Post by: VileZambonie on September 18, 2018, 04:57:31 PM
Measuring a non-precision machined surface is irrelevant and means nothing. If your pinion bearing preload is good, your backlash is good and your gear tooth contact pattern is good then, all you need to do is prove it by doing a nice burnout.
Title: Re: Ring Gear Backlash
Post by: Ronno6 on September 18, 2018, 07:19:55 PM
Measuring a non-precision machined surface is irrelevant and means nothing. If your pinion bearing preload is good, your backlash is good and your gear tooth contact pattern is good then, all you need to do is prove it by doing a nice burnout.

Lookin' forward to it!
Title: Re: Ring Gear Backlash
Post by: VileZambonie on September 19, 2018, 03:48:37 AM
Good Luck!
Title: Re: Ring Gear Backlash
Post by: Ronno6 on September 19, 2018, 10:31:19 AM
Measuring a non-precision machined surface is irrelevant and means nothing. If your pinion bearing preload is good, your backlash is good and your gear tooth contact pattern is good then, all you need to do is prove it by doing a nice burnout.

Yup. That, and......hoping I can stop without locking up the new JB5 rear brake s.......
Title: Re: Ring Gear Backlash
Post by: Ronno6 on September 26, 2018, 04:58:46 PM
The job is done!
All seems to be in order: no whining or growling.

The truck even stops without skidding !
Title: Re: Ring Gear Backlash
Post by: VileZambonie on September 27, 2018, 04:45:28 AM
Nice! congrats