Setting-Up a Pattern, Dana-60, Does it matter?

Transmission to Rear-end

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MileHighMan
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Setting-Up a Pattern, Dana-60, Does it matter?

Post by MileHighMan » Thu Sep 14, 2006 10:14 pm

Hello guys, I am setting my dana 60 up, and I have the pattern very close. My question is. Is it really that important to get it perfect? If not perfect, does it weaken the rear? With the hedders open I wont hear it whine. I put a dial-indicator on and the backlash is .007". This falls within the specs Of .006-.010. I would think that, a loose setting would be better than a tight one. I have'nt buttoned it up yet , so ,Your thoughts please. Thanks, Dan.

Cobra

Post by Cobra » Thu Sep 14, 2006 11:57 pm

An important fact is that the pattern will rise under power. Very high horsepower cars often have to run backlash close to zero to prevent broken parts!

CoMaxRacing
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Gear Pattern

Post by CoMaxRacing » Fri Sep 15, 2006 9:54 am

If you have enough shims to set the pattern perfect then why not do it. The gears will last a lot longer if they are set perfect. As far as lash Cobra was exactly right on high power cars with trans brakes or clutches you need less lash. The more lash you have the farther the two mating surfaces have to travel to contact each other. They will slam together if you have a lot of lash causing possible failure. I always set gears that are drag only on the low end of the lash spec,sometimes a hair lower.

Hope this helps

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Dana 60

Post by MileHighMan » Fri Sep 15, 2006 10:40 am

When I say my pattern is close, according to my reference sheet, my pinion shim is correct, and it says to increase backlash. I have .007 now, and did'nt want to open any further. Any Opinions? Thanks, Dan.

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Gear Setup

Post by CoMaxRacing » Fri Sep 15, 2006 5:19 pm

If you have got the lash set withing the tolerance I would leave it alone. If you want to spend the extra time moving shims on the carrier to increase the lash a bit no problem. But if .006 is the low end of the spec and you have .007 then thats sound fine to me.

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rear end

Post by MileHighMan » Fri Sep 15, 2006 9:23 pm

Thank you CoMaxRacing, and all. I spent alot of time to get this thing as close as it is. I'm not lazy, but I will pay some-one to do it next time. I think I will have little or no trouble at this time because i'm only foot braking. Now, my question was, does it really matter if it's perfect? I was watching some prostock racing not long ago, and when the car was being filmed at low speed, with engine off coasting to a stop, It whined. Gears? or Transmission? Any Answers? Thanks Guys. Dan

Cobra

Post by Cobra » Fri Sep 15, 2006 10:13 pm

As backlash is tightened noise is in the equation.

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Re: rear end

Post by SupStk » Sat Sep 16, 2006 8:18 pm

MileHighMan wrote:Thank you CoMaxRacing, and all. I spent alot of time to get this thing as close as it is. I'm not lazy, but I will pay some-one to do it next time. I think I will have little or no trouble at this time because i'm only foot braking. Now, my question was, does it really matter if it's perfect? I was watching some prostock racing not long ago, and when the car was being filmed at low speed, with engine off coasting to a stop, It whined. Gears? or Transmission? Any Answers? Thanks Guys. Dan
I just noticed this post and probably you have it together and in the car by now. This might work for future information, I'll offer my .02 anyway.

As you know tightening the backlash will move the pattern towards the tooth toe (ID). Hypoid gears patterns tend to climb under load away from the toe to the heel. Setting gear sets by the dimensions specified will get you close, often my finished setup will vary a few thou. I don't consider the manufactures dimensions gospel. Just one other pointer if you are spinning the gear assembly by the ring gear and can feel or hear the tooth engagement, it's gonna be noisy. Noisy gear sets soak up horsepower.

About the Pro Stockers gear whine, Liberty's are noisy in gear. Dual clusters and straight cut gears are the reason.

Ed-vancedEngines

Post by Ed-vancedEngines » Sun Sep 17, 2006 1:10 am

Gear tooth contact pattern is very important but all I can see getting discussed is the amount of backlash?

The long and short of all of this is that there are different behaviour charastics with a Nickel 9310 ally Pro gear than there is with a 8620 alloy street or circle track gear.

Also I do not set either gear tooth contact patern or backlash the same on all applications for different uses.

I suggest to go to Randy's Rong and Pinion or whatever it is officially called and spend some time looking at and downloading their tech sheets.

When gears for any purpose are originally cut they are cut to be a perfect mesh when in only one position of mesh. Anything different is a compromise. When setting up a big monter high horsepower car with 9310 Pro gears I usually favor the tooth contact pattern to be nearer the ID of the Ring teeth but not so far to the inside as to go off of the tooth. You still want a full tooth contact no matter how you do it. Likewise that will pull the coast side contact to be near the center but with a slight bias toward the OD. When Full instant torque suddenly hits it things will move. The drive contact pattern will move away from the previously biased towrd ID position to near the center and theoretical ideal position when under full load. As one contact position moves in one direction the opposite will occure with the coast contact and both will come closer toward center while flexing under extreme loads.

The same does apply to backlash as set in the setup process. Let us say that you are setting up a Pro 9310 gear in a Pro Mod Nitrous car with maybe 1,500 plus lbs of instant torque to the recommended spec of .006 to .010 backlash. That backlash will change radically while under load and will increase a big bunch, so we have to fudge on the specs some and set it up at say maybe .002 to .004 backlash which is very tight according to the book. In racing gear sets we also do not use heavy viscosity rear lube oils, so the thinner viscosity rear lubes will still be able to get in that little tiny .002 to .004 clearance between the gears.

On a street car or mild performance car the gears will not flex as hard even if they are pro Gears so setting it up much closer to MFG specs of backlash is more desireable and also the gear oil used will likely be of a thicker viscosity so it will need more clearance to get between the gears for lubrication.

If using the harder and more brittle 8620 gears then I suggest to stay much closer to MFG recommendations of gear tooth contact pattern and backlash.

Hope this helps a little.

Ed

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