I was putting the 1030 rear in the Canuck last night and noticed that I may have a small problem - may be no problem at all - I simply don't know enough about rear differentials blowing up to evaluate the problem. Here's the deal, I've pulled the differential carrier to fit a TrueTrac and make fabrication easier (the axle is so much lighter with everything out of it).

While it was apart, I noticed that the pinion had two very small cracks eminating from the gear tooth inwards, they are hairline cracks and are only noticable if I run my fingernail over them. This may be normal, maybe not. They are probably 1/2" long, one leading to the gap between a tooth, the other is not. So, does this mean I'm in the market or a new pinion? Is this normal? I don't want the thing blowing up now that I've got this much time and money invested.

Thoughts?

Normal or not, cracks are probably bad. What ratio is that axle? I've got a 4.10 R&P for a 1030 sitting in my shed, unsure of the condition but you're welcome to look at it next weekend. There are a few axles at PYP so there might be a 1030 with a taller final drive as well.

The bummer is that you're going to have to set up the new R&P once you pull the pinion.

I've got a 3.73...now I'm going to have to check on the ring size to see if it is a 1030 or 1031. I'm guessing I'll have to take the entire axle?
I've already got the damn new bearings installed on the TT as well -

Are you sure it's a crack and not just a flaw? An LPI or MPI will show if it's a crack or not.

Who would I call to check that? They look like regular old stress cracks - but at this point I'm game for a simple flaw! By the way, it is definaltly a 1030 as the ring gear is 7.25" - so I have a lug eared, smooth bottomed, dual ribbed 1030 - how strange is that (I think there are a few folks on TB that would have fits if I showed them photo's - worlds colliding).

The stupid part is that I have all the brackets set up for this axle and if I go to the PYP I'm going to have to pick up an entire unit to get a new R&P. Given that it is a 1030 - I can also get standard a standard Dana 30 gear set right?

Call any quality control or inspection place. There are probably one or two in Lethbridge. They'll do sonic checking, Liquid Penetrant Inspection, Mag Particle Inspection, radiography, you name it. The oil & gas industry uses these guys lots. I'm pretty sure Eastwood also sells LPI dyes for checking various stuff (aluminium cylinder heads).

It'll probably be a lot easier to take the whole axle from PYP, but if you're creative you might be able to get a R&P out. Dunno if they'll charge you much of a difference, though, and this way you'd get spare axle shafts in case one of yours is bent.

Dana 30s were mostly used in front axles. Some of them have their teeth cut backwards so that the thrust surface is going the right way for them. Some of them use a high-mount pinion for more clearance, and I'm not sure if they use the forward cut gears or not. The first year ('87?) of Ford Aerostars also used a Dana 30, by the way, so you might be able to find taller-geared R&Ps easier that way.

I'll see if I can find something locally. I'll assume that if the hairline is only on the surface of the snout and not extending down into the gear itself then I should be OK. Summit sells the R&P for $200 plus $95 for the install kit, but I'll check mine first, pull PYP next, then go to Summit.

I had a good look at the pinion tonight and am pretty sure that what I thought were cracks are not going to cause a problem. I thuroughly cleaned the pinion and inspected the "cracks" and have determined that they are only on the ground section of the front of the pinion, they don't go down into the tooth area and are likely scratches, not cracks. The fact that one points to a tooth valley is luck - the heat treated part of the gear shows only normal pinion wear, but no cracking.

I couldn't find a dye kit in town, but did the following. I cleaned the area with engine cleaner. Just like a dye kit, any crack will wick the cleaner, so I then wiped off the cleaner and gave it a quick shot of marking paint (if the cleaner is in the crack it will discolour the paint). No cleaner came out of the tooth. Nothing much came out of the line, so I now think it is just a scratch on the pinion - nothing more. I cleaned the experiment up with break cleaner and am ready to paint and get this axle put back together. Thanks for your help Matt.

You're sofa king smart! I would never have thought of that.

You don't become a certified Post Hole Digger without being smart, huh?

Fred Eaglesmith rules...and I've dug my fair share of post holes