Please help me with my rear end.

[Tabcon]

I decided to tackle rebuilding my rear end, the one on my car that is, and I've completed everything with the exception of installing the pinion and ring gears. The instructions that came with my 4.11:1 ring and pinion set indicate that the pinion height must be set at 2.213". However, they do not tell me what to use as a reference to find this height. The factory manual mentions nothing of pinion height, only checking the footprint of the crown and pinion with dye. When I broke down the 3.7:1 rear end I found that the pinion had two (2) .010" shims installed. If I reinstall the new pinion and use shims of the same width as what was fitted originally and then blue the teeth on the crown gear to check the footprint of how everything meshes, will this be sufficient, providing of course everything meshes correctly?

 

[TR3driver]

That's the idea, Tab. Get the tooth pattern right, and all the preloads right, and you are good to go. The measurements are supposed to be a head-start on getting the pattern right; as otherwise it's a rather tedious process to assemble everything, check the pattern, take it all apart to add & remove a shim (once you get the bearing loads right, you always add & remove the same amount), etc.
Unfortunately, it's apparently common for replacement bearings to be slightly different widths than original, I wound up having to make rather a large change in shim to get my Stag diff preload right.

 

[trfourtune]

It will be a good starting point, but i doubt it will be dead on with new parts. You might end up being an expert by the time you are done re and re-ing the diff to get the shims right.
Rob

 

[Tabcon]

Thanks, that's sort of what I thought, but they make such a big deal out of the pinion height I just wanted to make sure.

I made a "dummy" out of my old pinion by polishing down the shaft enough so that the bearings slide on and off easily. This way, the whole process of off and on to check alignment shouldn't be so bad.

 

[TR3driver]

But wasn't your old pinion 3.70? They aren't the same, even in the same ratio ... which is why the dimension comes packed with the gear set (or etched on the face of the pinion).

 

[startech47]

I need to check the pattern on a rear. What should I use to coat the gear teeth to check the pattern and where is it available? The blue looks like Dychem. Some one posted about buying something at the art store.

Thanks, Phil

 

[tomshobby]

I need to check the pattern on a rear. What should I use to coat the gear teeth to check the pattern and where is it available? The blue looks like Dychem. Some one posted about buying something at the art store.

Thanks, Phil

Prussion Blue

 

[startech47]

Where would I obtain Prussion Blue?

 

[tomshobby]

Try a place that sells machine shop supplies.

 

[martx-5]

It's generally called Dykem Blue.

 

[startech47]

Thanks,

I forgot that Dykem blue is Prussion blue. I have a spray can in the basement next to the milling machine.