Rear diff gear pattern

[pontiacgp]

I was taught by a pro who builds a bunch of rear ends for racers and street cars, he always set them up with the paste. You have to be really off to blow the rear. The further you are off the best pattern the gears get noisier. It's hard on the ears listening to a rear end howl. Since these are new gears don't forget to put a magnet in there

 

[Collector]

I was taught by a pro who builds a bunch of rear ends for racers and street cars, he always set them up with the paste. You have to be really off to blow the rear. The further you are off the best pattern the gears get noisier. It's hard on the ears listening to a rear end howl. Since these are new gears don't forget to put a magnet in there

Good one !! never thought of that one ! thanks

 

[Collector]

Have the backlash set at 0.006" its a US Standard gear ring and pinion set .
In the booklet that came with the gears there a table sheet where the set-up specifications are printed.
There is something called a 5 cut and a 2 cut , if you look at the chart i am in spec with both types of cuts (?) on the old 5 cut i am at the minimum and with the 2 cut(?) i am at the max of the backlash.

Gear pattern looks like this with 0.006 backlash

Let me know what you think okay ?
tnx John

 

[pontiacgp]

You can see by the pattern it's a 5 cut gear. If you measure the heel it will be taller than the toe with a 5 cut gear. I never have the backlash set to the minimum with new gears.

 

[Bonnewagon]

It looks too close to the toe on the drive side. Refer to this chart.http://www2.dana.com/pdf/5717.PDF

 

[Collector]

Tnx for the link (its printed) and i will have a go again at it next week, i have an invalid wife so i dont have much time to fool around with the axle.
I will get there in the end.
tnx

 

[Bonnewagon]

Glad to help. Hey man, family comes first. That's why I have so many unfinished projects. It takes a few tries to get it right, but is worth it in the end. After all, you are doing something that very few people still have the skills for. A properly set up rear will be quiet and outlast the car.

 

[Collector]

FWIW i have a gut feeling i need to bring the pinion a little more inwards.

 

[techg8]

my two cents on this last pattern: Its pretty close but in need of some fine adjustment.

judging by the very defined, very flat edge to the pattern deep in the ring gear teeth on both drive and coast side, I would say the pinion is a little too close. Decrease pinion shim a few thou to bring the pattern up the face of the teeth a little.

As for backlash, its too tight at .006b/l, so the drive pattern is a little too far to the toe of the teeth. I would set b/l .008-.010" myself. keep in mind that the change to pinion shim will have an effect on the existing backlash as well, so change the pinion shim first then play with backlash.

youre smart to be thorough, running patterns and adjusting. It ensures a good result, and you wont have to get in the rear again once youre done. good job.

 

[Collector]

Had a go at it again:
Pinion shim was way to thin according to the manual, it says it has to be .035"it was a lot thinner i mean a lot !! so put in 2 .45mm shims on the pinion (Equals .035")put in the ring gear again and marked as usual, backlash is still a bit tight at .007" but thats easily adjusted.
Please take a look at the pattern and give me your opinion please.