8 3/4 re-shim

[62Dart440]

I bought a 67 charger in October, it needs a ton of TLC. I took the open 8 3/4 apart and replaced the open center with a cone type sure grip. When I put it back together I cannot get a good pattern on the ring gear. It is heavy on the toe drive side and heavy on the heal coast side. According to the service manual I need to put in a smaller shim on the pinion gear. I did not look at the pattern before I took it apart, I made the obvious bad decision and assumed it was done correctly. I had the back lash set at .007~.008 over 4 places on the ring gear. So here is my question, can I re-shim the pinion without making the gear set noisy? I do not know if it was noisy before I took it apart, I haven’t driven it.

 

[khryslerkid]

What number carrier. I'm thinking 489 with the cone.

 

[62Dart440]

742, the cone actually came out of a 741 housing the my uncle ran in his stock car in the 70s. It looked like it had never been run.

 

[khryslerkid]

You can put a smaller shim behind the pinion gear and add the same thickness shim on the front bearing to keep the preload the same. Check the bearing preload with a inch lb. torque meter.

Edit: I ment subtract the same amount from the front bearing to keep the preload.

 

[1 Wild R/T]

I would not change the pinion depth, It's run at that depth, if you change it I'll guaranty it'll be noisy... As it is you might get lucky.... Set the backlash a touch looser & hang a voodoo doll off the rear crossmember....

 

[oldkimmer]

Can u post a good pic of the pinion gear? If it’s running off the end of the teeth it will never last. Kim

 

[62Dart440]

If you are talking about the bearing side of the pinion, yes it looks like it is the wear mark is running off that side of the pinion. I will get a better pic when I get home. But it looks like it runs off the bearing side 1/3 of the edge of the pinion gear.

 

[dvw]

Re shimming a used gear is an exercise in frustration. Either its been run forever with a poor pattern or not. You're not going to fix it. Run it and see. Or replace the gear set.
Doug

 

[62Dart440]

I like that idea best, DVW. I will just run it and see what happens, at this point I just want to start to reassemble the back half of the car. Thanks to all for the assistance.

 

[oldkimmer]

I was talking about the rear of the pinion. I agree: u may as well run it as is. Kim

 

[Fran Blacker]

20/20 hindsight should've checked backlash and got a picture of the gear pattern. Did that on mine, .011 backlash on a 80,000 mile rear. Original owner didn't order sure-grip.

 

[1 Wild R/T]

20/20 hindsight should've check backlash and got a picture of the gear pattern. Did that on mine, .011 backlash on a 80,000 mile rear. Original owner didn't order sure-grip.

Like I mentioned in my earlier post, he should loosen the backlash... off memory the spec is .008-.012 and typically when new they are in the .008-.009 range but as they accumulate miles things loosen slightly & .011 -.012 is common...

Setting the backlash tight will reduce clunk when putting it in gear but it'll increase the likelihood of gear noise...

 

[62Dart440]

I understood what you meant about not changing the shim in the pinion. The gears are 4:10 and were installed approx 7~10K miles ago, according to the PO paperwork I received with the car.
I was referring to reassembling the rear of the car...brakes, fuel tank, and lines and such. The PO decided to blow air backwards through the fuel line and thus making the tank bulge at the bottom and it blew the screen in half.