8.8 diff backlash

Don't use pinion depth to adjust backlash.

Pinion depth is set long before backlash is adjusted, pinion depth is set where it is supposed to be and then left alone. To be done properly, it should be done with the proper measuring tools. The ProForm tool is $100 thru Summit racing. Aftermarket side shims for backlash can be had from any of the common vendors that deal with rear axle parts, Randy's Ring and Pinion is probably your best bet. the aftermarket shims can be combined to achieve what ever size you need. Backlash and bearing preload need to be considered all at once when selecting the correct shim size.

You are trying to cure a high-speed vibration by adusting back-lash ? I think your barking up the wrong tree. Try balancing and rotating tires. If the rear-end isn't making any noise I wouldn't worry about it.....

this would depend on gear pattern both pinion and ring may have to be shimmed to find suitable pattern i have pinion bearings which have been ground out a bot for ez removel and addand subtract shims to achieve a proper pattern

h u r c a s t

No point patterning a set up that is known to be assembled wrong and has way too much backlash.

Indeed, that is the procedure. The OP would be well advised to start from scratch, or have someone with the tools and knowledge to start from scratch.

Mine aren't "ground out", I had them honed on a Sunnen Rod hone.

Would it not be simpler to use the correct tools (which your dealership should possess) to select the correct pinion shim in one simple operation? I would think that a Master tech would have passed Specialty 36 and learned how to use these tools.

lmfao warman admitts to steeling tools

THIEF

hurc ast

lmfao tell em how its done tom i need a laff

hurc ast

jim is no technician he is an oil boy

h u r c a s t

I don't have the tool required to set pinion depth, and don't want to buy it for a one time use. That was the purpose of my question regarding backlash and pinion depth. You don't think setting my pinion in 5 or 10 thou will help me set my backlash properly with the shims available from Ford? __________________________________________________

The pinion depth shim is intended to align it with its matching ring gear for perfect mesh. The ring gear shim is used to establish the correct backlash.

Think of the pinion near the ring as a cone near a ramp. If the ramp angle is 30 degrees for example, the pinion could be moved .020 axially to bring it .010 closer to the ramp represented by the ring gear. However, if this were done, the movement would mismatch the meshing geometry, leading to higher shear loads, early wear, and ultimate failure.

Good luck.

Rodan. ____________________________________________

Sorry to come back in so late, Steve... If worst comes to worst, using a frsh shim the same thickness as your old shim should put your pinion depth within about 2 or 3 thou of desired. While not the best situation, it is seviceable.... Tooth contact patterns can be ever so imprecise at the best of times.... one tech might say it looks a tad to the heel - another says it looks good and another may feel it's a bit toward the toe... As techs, one of the worst things we can do to ourselves is to get lost in that neverland of shim swapping.

I've been forced to work in some pretty primitive conditions in the past.... I've seen diffs that should have howled like a coyote in heat that were quiet... seen diffs start out with a noise and get quiet and seen diffs start out quiet and get noisey....

Now that I have access to the tools (why steal them when I can use them whenever I want..... though most big city shops refuse to give their techs keys...), I prefer to use the tools and remove interpretation from the equation. For your case, you have to start somewhere..... if you can't beg/borrow/rent the tools, subbing the original size shim should deliver a reliable repair most of the time.

HTH

I had also considered what you're saying Jim but from the sounds of his first post, he bought the car this way and the original shims are long gone. Thus, he really really needs to do an actual measurement.