Swapping the differential isn't the same as setting up the gears.  You will not have to touch the pinion, just swap the ring gear onto the new diff and set the backlash.  On a 9" all you will really need new are the carrier bearings, and that's just because you won't be able to get the old ones off your existing diff.  As for tools, you need a dial indicator and magnetic base to measure backlash, and you need the tool to spin the side adjusters, but you can just make one from a couple bolts that fit the holes and a length of bar stock as a handle.  I still use the dial indicator and magnetic base I bought from Harbor Freight for which I had to make a bracket to get the indicator to mate with the base, but I've been using it for like 15 years and it cost me maybe $35.

You can check the gear pattern if you really want to, but seeing as the gears are used I would only look at the coast pattern. 

Hmn, that's a good idea I never thought of...

Actually there's nothing wrong with installing bearings with a hammer.  I did this for years before I owned a press.  Use brass drifts and drive only on the bearing's inner race.  I never had a problem with a trans, t-case, or rear I built this way.  Its a good way to go if you don't have need of a press often.  Eventually I purchased a Harbor Freight press that I now use. 

You're welcome.  You don't get any repeat business from me because I've never had a failure of any bearing I've ever installed.  Like most things in life there are multiple ways to achieve the same result.  Also, as with most things, the skill of the person doing the work means a hell of a lot more than the tool they use.  I learned how to use hammers and drifts from an old mechanic who serviced fighter aircraft during WWII.  Yes, it shocked the hell out of me the first time I saw him do it, but after watching him it made perfect sense. 

A brass drift isn't going to hurt a bearing, unless you smash the cage like an idiot.  You drive the bearing on evenly, side to side.  In inexperienced hands its actually safer, because even a small shop press generates 5-20 tons of force and its easy to damage things with that kind of force.  When you drive a bearing on you don't have near that much force at your disposal, so if it gets cocked, or something else isn't right (fit is too tight, etc.) you have a chance to correct it, whereas with a press you might well not feel the problem and push right past it damaging the parts in the process.  There was an article in the March 2016 issue of Classic Auto Restorer about this exact problem, where the author damaged a rare and hard to get part for one of his cars with a shop press. 

Presses are faster, and I think I paid all of $90 for mine at HF, but if I was stuck and didn't have a press I wouldn't hesitate for a second to drive a bearing on the way I did years ago when I couldn't afford a press or to pay someone to press stuff together for me.  I think I paid $10 for a set of brass drifts.  They get chewed up, bent, etc., you just grind them true again or bend them back straight.  They last fairly long, in fact I still have most of that first set I bought. 

It must be hard to be the smartest guy on the site.  All my years of experience are now down the drain.  All I offered was some advice to 65svt based on my own experience with a TruTrac install and now you are dragging this out as usual - with bad recommendations to boot.  You have managed to do what Barnett failed to do....

GPatrick I had a great sarcastic comment but I'll take the high road, because sarcasm and personal attacks don't help the OP.  It is possible for people, even people of great experience and skill, to have different opinions.  If you want to claim you absolutely must always press on bearings go right ahead.  I'm not going to, because I've done it another way and had nothing but success.  But I'm done arguing about it because I don't need you to be wrong so I can be right. 

Sorry 65svt, I hope you got what you needed.  I should mention, it should go without saying, but when you install new bearings on the new differential be sure to pair them with new races.  I re-read this whole thread and realized I wasn't specific about that. 

I have to respectfully disagree.  There's simply no way a brass drift is going to do damage to a bearing.  A steel drift maybe, but not brass; its too soft and will simply deform before damaging anything.  I've rears with over 100k on them that I rebuilt this way over a decade ago with no issues, transmissions used in racing applications where if something was going to fail it would, yet not a single failure. 

If the concern is uneven application of force, you are more likely to do that with a press, because most of the cheap presses we all use aren't really true.  It's easy to start a bearing cocked if you're not careful.  You can't start a bearing with a drift cocked; it simply won't go on like that. 

If the concern is impact stress, again, brass vs. steel; steel wins.

I get it, it seems like a hillbilly way to install bearings, some ham fisted guy whacking them on with a hammer.  You simply have to look past that as I did when I first saw it done, and consider what's really going on.  The guy I learned it from knew a hell of a lot more than I did at the time, probably still does, but I can tell you, everything he ever fixed stayed that way, and everything he ever told me was right from this up to how to drive a Model T.  It wasn't that he didn't have a press; he had like three, one the size of a truck.  But at 17, as now, I came to the conclusion that a guy who was 50+ years older than me, and had been a mechanic for most of that time probably knew more than I did.  So I stand by the method I learned from a guy who never once steered me wrong. 

Cannot argue with the differing logic expressed above, but might I suggest once more that the job be done by someone with experience and the correct tools, whatever they may be.  I've set races both ways with success, so the argument posed is really picking at nits, which only serves to confuse some avid hobbyist. Presses, properly used, seem to be preferential, but brass drifts are an essential in my tool box.  You cannot go wrong with the wisdom of tko or ms.  I have never had serious issue with their posts.  Mostly just boils dowm to preference.
Best,
Al

Al comes in as the voice of reason!

For someone with no experience I'd suggest just paying someone to do it I think.  What's it going to cost to have two bearings pressed on?  $50?  That's the safest of all bets for sure.

On the other hand, you never gain any experience by not trying anything new.  That's a judgement call we all have to make at some point on our various projects.  I've never been afraid to try something new for fear of screwing it up.  I believe that if you show me someone who's never made a mistake I'll show you someone who's never learned anything.  I've screwed up plenty, and learned plenty from it.  So the question is, if you want to learn to do something new is it worth a $90 investment in a tool you may never used again to learn it?  On the other hand, for $10 you can have a method that works for the rare occasion when you need to do it.  I promise its not that hard.  If you can properly install a seal using the same method you can install a bearing. 

Having worked for John Deere for nearly 30 years now I will offer up the way JD recommended to install axle bearings and transmission bearings, it is by heating the bearing to 350 degrees either in oil or a toaster oven, we used a deep fryer for many years until one of the techs spilled hot oil over his hand, luckily he was not burned more than like a slight sunburn, then we went to the toaster oven, granted this will not work for sealed bearings but it works great for Timken tapered bearings. 

Served with a side of headlight fluid.

My car never ran as good and sounded better after I replaced the O/E muffler bearing. Also I found that sauteing them gave a mellower sound than deep frying.