Anyone as of late try swapping a GM 3:42 gearset "thick" ones just like the original 2:73's (not a richmond!!!) into thier 2:73 open diff with drum brakes. I have tried every possible combination of pinion shims and carrier shims. In addition i am using a crush sleeve eliminator, also it appears that I almost always get the carrier preload and pinion preload right but when i go to check for backlash by hand as well as with the dial indicator i am just getting a very very large amount of backlash. In fact i tried to use a little gear marking compound to at least see where I stand but the ring and pinion wont mesh together to even create a pattern on the ring gear teeth. In conclusion I was thinking that maybee I need to use a ring gear spacer as this would explain why I am having such a large amount of backlash

 

Do you have the correct gear set for your carrier?

JamesC

 

Its for a 10 bolt with a 7.5 ring gear which is what our third gens have

 

IIRC (and sometime I don't), 2.73 would be a series II carrier, 3.42's a series III.

JamesC

 

By the way could it be that i am trying to put a 3 series gear hence "3:42" on a 2 series carrier "2:73" ??? and in actuality they look almost the same dimensions wise, but have totally different clearences. I also tried to match my set of various shims to the factory cast iron shims that were originally in the diff carrier when i took the diff apart

 

also when i place the two ring gears side by side they also look the same in terms of the distance from the carrier mounting flange up to the convex side of the gear teeth.

 

The "thick" 3.42 ring gear would be around 3/8" thicker than the "normal" 2.73 one. That's MASSIVE: the part of the gear behind the teeth, would be about TWICE as thick. So if your 2 gears are about the same, then the 3.42 ISN'T the "thick" kind. That's probably your problem.

The "thick" difference, like I said, is about 3/8" more or less; or, about .375". Normal shim pack differences are usually less than .020" or so, from one gear set to another; usually MUCH less than that actually. Gears are pretty precise, it's HOUSINGS that vary (i.e., you're actually shimming the housing to the gears, not shimming the gears). IOW, your error is AT LEAST 20 times as great as it should be. So it sounds to me like you've got a bunch of stuff there that has no chnace to work, yet.

You either need a 3 series carrier, or a set of the "special" gears, or a ring gear spacer. Since you've already got what you've got, I'd recommend a spacer.