Hi...

Just wanted to show you guys what kind of job I have done to my GM 7.5 10 bolt rear end.

I bought a new Eaton Posi differential with a Yukon ring & pinion set.
Wanted another rear gear ratio basically on my 87 Camaro.

Anyway: I work as a mechanic and build thrusters and components to ship vessels so I am familiar with gear sets and hydraulic systems.

But I haven't done this swap on a car rear end before so I just wanted to show you how I've done and hopefully some comments will appear.


Here is a picture of the ring and pinion next to the ring and pinion I am going to install at my work...As you can see they are tiny compared to my usual job...



Here you can see the concave side of the tooth of my gear pattern.




Here is a picture of the convex side of the gear wheel.


Anway, since this was my first time of this type of ring gear I wanted to do the job slowly so I learned the way they are set up.
I am not used to change the pattern to center between the root and face actually. We are more conserned about adjusting pinion so the gear pattern will be in center of the toe and heel. And most of the times the pattern will be pretty much sentered when it comes to root and flank.


Anyway I have done a couple of shim changes on this pinion and I think this is the best result I could achieve. I know some of you is gonna ask why are the tooth painting white and now yellow like the ones you probably use. And that is because I used the regular white tooth paint we use on our gear sets and that paint should be more than qualified enough.


I also have a question about the pinion preload. You see here in Norway we don't use lbs/inch torque wrenches so it was hard to find a torque wrench with that scale.

I came up with an other idea that I think might have worked out really good. Since the bearing preload was going to be something between 12-15lbs/inch I have to convert those to "gram" force per meter.

And then I multiplied it with 5 and used and made a bracket that went 20cm out from center of the pinion to both sides. Then I applied a hook on the 20cm mark on the bracket.


Then I measured the amount of "grams" that should be for 12lbs/inch and the amount of grams on 15lbs/inch.

Then I tighened the nut slowly and tried to hook on the lightest amount. (it was actually a little bag with nuts)

then tighened the pinion nut until that bag didn't move the arm any more.
Then I tried the heavier bag and the pinion turns around slowly.

I mean, this must be somewhere between the preloads right??

I know some of you think of me as a stupid man now but this was the easiest method with now inch/lbs availible in this country..

I didn't want to wait 2weeks until I can receive one that I can buy from US...

Anyway, any comments will be highly appreciated..

Thanks

 

Looks to me like you used your head pretty well and came up with something that worked. I think you did a fine job. I usually set the preload closer to 20 inch pounds, but you will probably be fine where you are. I thought you would use Newtons instead of grams.

 

Thanks for that positive comment big gear head..It really helps on my self-confidence. You see every time I am doing something for the first time I actually use a lot of time and thing goes slowly because I am a little bit afraid of doing something wrong. But most of the times I just have a little conversation with myself and then I figure out most of it if I ust consentrate..

Since you gave me that good respond on my thread I think I am almost ready to put the rear end back to the car with it's new gears..

The engine on my car is also finished breaking in after a rebuild I've done and some performance parts installed...Can hardly wait until I hit the road again..