ive just set up a toy 8" diff by the books(all preloads and patterns are great)
i was told by a longtime mechanic about the "overall" preload i.e., how many inch punds the whole assembly has. has anyone ever done this? i just assumed that if i set everything right, i wouldnt have to check the overall. if the overall wasnt right, id have to adjust other things, which might throw off the pattern. any comments?

When I set mine up, I couldn't find an "Over all" pre load. So I figured since all of the others were set, the pattern was right and it didn't make a Grind, Thump, Bang or other wise bad sound I was good. Check the pattern in a few days and again in a few weeks and you will know for sure.

I don't know about a Toy, but I can give you some numbers on a Dana 30, 35, 44.

Chrysler uses a TTR (total torque to rotate). Somewhere around 45 in/lbs. This is measured with a high quality dial torque wrench. This is the amount of force required to keep it moving, not the "break force" which is the amount to start it turning.

The way it is arrived is the PTTR (pinion torque to rotate) spec. plus the carrier.

Timkin recommends that 30 in/lbs. should be the preload for the carrier. So you devide the ratio by the 30 in/lb. spec, and add it to your pinion spec.

So if you had a 4.10 ring and pinion and a 30 in/lb. spec on the pinion preload, you would devide Timken's 30 in/lb. by 4.10 and get 7.3, and add it to your pinion and get about 37.3 TTR.

If you change a pinion seal on a crush sleeve pinion, you are suppose to measure TTR, and add 5 in/lbs when re-assenbling.

What I know... worry about pinion preload without the carrier in it. From what I've been told (toy and 9" 3rd members I would think different) you can't have too much carrier preload. your mainly limited by how hard you can beat the carrier back in to the housing with a deadblow hammer. I'm guessing on a 3rd it would be easy though to possibly set too much carrier preload.

The problem that Chrysler had with the aluminum 44's was diff case preload. From the factory Dana set the gears up perfect. Then they pressed in the steel tubes to the housing. This greatly increased the carrier preload, and caused massive failures in just about all Grands. When you rebuild them, if you remove about .008 shims on both sides of the carrier, preload will be just about right.

This is the main reason for the TTR method of inspection. It can give you accurate numbers for setting up the new gears. The aluminum housing 44's will last just as long as any other diff if set up properly using this method.