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67drake · 05-07-2009, 10:48 AM

This is where I am at with a .042" shim under the pinion. Looks maybe like the pinion is a hair to far from carrier centerline? Funny thing is I had .044" under there previously,and it looked as though it was definitely to CLOSE. I wouldn't think that this setting is so touchy that putting it at .043" would be perfect. Also there is no way I can get exactly .043" with the shims provided with the rebuild kit that I'm using. So it is either .042" or .044". What is your opinion of the pattern as is?
These pics are taken at opposite places around the ring gear,for an overall view. BTW,I'm showing .003" lateral runout on the ring gear,what is within tolerance? All surfaces were de-burred on ring gear,spacer,and carrier,and put together oiled,and clean.Backlash varies anywhere from .005" to .008",depending on where I measure it.
Thanks!
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J_JAMNIK · 05-07-2009, 10:53 PM

I think the pattern looks fine. Is the backlash good?

jtheisen · 05-07-2009, 11:01 PM

I agree. Pattern looks good.

67drake · 05-08-2009, 07:53 AM

Cool.
I checked the backlash in 90 degree increments around the ring gear and I got readings from .005-.008"
Thanks guys! This is my first rear rebuild ,so I just wanted to double check my set up before I have the new pinion bearing pressed on.

Cliff R · 05-08-2009, 08:37 AM

The pattern is well positioned, and very close. I like to see a "speeding bullet" shape to the drive pattern, with the heaviest part of the pattern centered slightly toward the toe. The front portion of the pattern toward the "toe" should have a round shape, the rear like the tail of a comet. The slight "slice" on each end of the pattern may simply be from not enough load applied during the test, as the coast side looks fine, and both patterns are show good depth, engagement, etc......Cliff

67drake · 05-08-2009, 05:24 PM

Thanks Cliff. I'm glad to hear it looks OK. I guess I was being overly anal about it,but I just don't want to have a "whiney" gear.

Cliff R · 05-08-2009, 09:54 PM

Even with perfect set-up patterns the gears can make some noise. Richmond gears in particular are probably the worse for noise, but are very strong parts. Richmond machines their gears so that they provide superior tooth contact under heavy load, so often they will "whine" some at very light load, then shut up the instant you load them.

I quit using them years ago, unless the customer supplied them, and we went over in detail why they may be slightly noisey in use.

Setting up gear sets involves EXACT precision, and attention to detail. You also have to correctly pre-load the bearings in addition to establishing correct checking patterns. Always do a final check after pre-loading the bearings, just to make sure it didn't move any.

Many years ago, before 1800 different companies manufactured gear sets, you could more times than not just re-use the original depth shim, establish acceptable back-lash, and keep on going. These days I've had to move carriers all over the place, and pinions considerable distances from the factory position. Not uncommong to have to do a half dozen or more set-ups to find the proper pinion depth, where I used to be able to do them with at most two changes.......Cliff

hal101 · 05-09-2009, 07:20 PM

hey great job

what is the new ratio ?

67drake · 05-09-2009, 10:33 PM

I picked this 8.5 up off of Craigslist for $200,guy thought it was a 66' Olds 8.2 rear. Turned out to be a 71-72' 8.5 posi rear,but it had 2.56's in it. Figured I'd pull my original 8.2 3.23 posi rear out and mothball it. The new gears I put in are 3.42's. I'm still kind of torn between the decision,I could not decide between the 3.42's and 3.73's.
Thanks for the tips Cliff. These are Yukon brand gears. A little noise is fine,I just don't want it to sound like a gear drive timing set.
Believe it or not this is where I started when I first set it up with the original .042" shim. Thinking the pinion was a hair too deep (and I wanted the experience of setting it up anyway) I then went to .046" under the pinion (too close to carrier),then went to .044" (still to close),so I put the original .042" back under it,and that's where it is at now. Guess I got lucky.

hal101 · 05-10-2009, 08:55 AM

yea always a tough call between 3.42 and 3.73

3.42 should be a nice boost in et without hurting highway crusing

someday maby i will do the same switch let us know how you like it

67drake · 05-11-2009, 12:28 AM

Quote:

Originally Posted by hal101

yea always a tough call between 3.42 and 3.73

3.42 should be a nice boost in et without hurting highway crusing

someday maby i will do the same switch let us know how you like it

I'll follow up this thread when I get the rear in. I still have to buy brakes for it,and install it so I can measure for the driveshaft cut. Problem is I have more time than $$ this year,so it may take awhile.

scott cedergren · 05-11-2009, 02:05 AM

Cliff may I ask what gears you like to set up/run? I have not had any problems with Richmond, but that does not mean that there is not a better gear out there. thanks

Cliff R · 05-11-2009, 07:02 AM

My first choice is US Gear, but we've had good luck with the Yukon gears to date.

Nothing at all wrong with Richmond gears, some run fairly quiet, but we've had a few that were noisey enough that the customers complained, so we quit using them.....Cliff

bnorris_74 · 06-17-2009, 07:46 PM

I'll add my .02 to this thread.
I just had Yukon 3.42's installed behind a TH350.
Quiet on accel but a little noisy on decel. Seems to have a sweet spot where they will whine and then it will quiet down.
I'm still running a 25-in tall 14in tire so I got a little more gear than I bargained for.
That's as good as excuse as I can think of to buy a set of 15-in ET streets and wheels for the rear.

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