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3.08 gears

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    3.08 gears

    Has anyone installed 3.08 gears in their 8.2 differential?

    I'm looking for a finished pinion gear shim thickness; that is, what was your final thickness on installation? This would help out a great deal and give me a good starting point as it is a hassle to adjust that shim since you have to remove the pinion gear and both bearings to get to it. Carrier shims are a lot easier to adjust.

    I haven't yet committed to this. I have marginal backlash and some mild, disconcerting noise issues coming from the differential.

    I'm running the standard 3.36 gears. Running the 3.08's will require about 220 fewer RPMs at 60mph with 26" tires. I think these will be high enough gears to still run my 3speed Syncro without bogging down 1st gear, but better for highway speeds.

    So, anybody do this? What was your pinion shim thickness?

    I'm not an expert by far, but I have swapped out many a gear set. But I thought the variation in backlash between the ring and pinion was more of a function of the manufacturing tolerances in the housing, rather than what gearsets are being used. I would install the gears, check the backlash, then adjust shims if necessary. I went from 4:11 to 3.36, to 3.08, to 2.73, and finally 2.56 and always found the backlash to be within reason without changing a single shim. (tell me I'm an idiot, it's ok) I once went from a 4.11 to a 3.08 on a 12 bolt without changing the carrier (used a spacer) and ended up with too much play which needed some shim work though.

    Side note: Decades ago, I worked in a shop rebuilding air cooled VW engines. The cam gear meshes with the crankshaft gear and the camshaft gears have a number stamped on it, each number increased the size of the gear slightly to maintain correct backlash with the crank. My boss told me "don't worry about it, If the gear is too loose, the movement is so small, it won't affect anything, if it's too tight, it'll work itself in". I've never bothered since, it's never been an issue, and today, I don't think anybody cares or is even aware.