Let's start with pay. One thing that is true for all non-director positions is that the compensation is dismal. The only ones making respectable money are senior management. PACCAR does not have a bonus structure for normal employees. Only senior management gets bonuses, which can be as much as 25% of their [already high] salary, and is based on yearly goals that they set. You know bonus time is near when your director has you drop everything and focus on their goals.
Raises are few and far between. There is a small pay bump every 18 months (or longer) - up to 6% when times are great (rare) and 3% or lower during average times. Getting a decent raise (which HR caps at 10%) is all about how you present yourself to senior management. There is a list of employees "deserving" of a raise that senior management goes through every month. They pick and choose a few people to give raises to, and move the others up or down the list. In order to get a raise, most people change teams or threaten to leave the company.
Benefits are OK. There is a 5% 401K match, which is paid yearly so that the company can hold onto your money for as long as possible. A pension exists, but unless you're planning on putting in decades of earning low pay with the company, it's hardly a benefit. Vacation starts at 2 weeks and goes up to 3 after 5 years. Medical benefits are average.
As for the work environment, everyone except for senior managers are in cubicles. Everyone is given the same, outdated Dell machine - even software developers. PC refreshes are few and far between. There was one refresh while I was there and management made a big deal out of it, so don't expect another anytime soon.
The atmosphere is stuffy. Corporate requires every employee to wear a suit. Other divisions require a shirt and tie. The IT division allows jeans and a collared shirt, which we've been warned can change at any time. Whenever somebody "important" (ie. the Chairman) visits, formal dress attire is required by all employees.
Good managers are few and far between, and it's even more rare for a manager to have any idea about the work you do. Most managers make it their life's work to impress their superiors, as that is truly the only way to move up. Because of this, don't expect your boss to have your best interests in mind.
Speaking from a software development standpoint, the work is not all that difficult. The hardest part is managing ever-changing requirements, and trying to get your head around the spaghetti code. Because most people (at least developers) leave within two years, the best coders are usually the lowest paid. Those that have been there 5 or more years are typically in it for the "long haul". They own a few applications and are content with their position in the company and with their tunnel-vision technical knowledge.
There are a few great developers, but for the most part the company is getting what it pays for. The interviews are ridiculously easy. Management has pressured interview teams to limit (or remove) the technical questions they ask an applicant for a technical position. If you make it through the interview process and receive an offer, make sure you negotiate for now and not the future. HR has lied to numerous employees, telling them that they can expect a raise within six months of being employed.
PACCAR has a lot of trouble attracting developers. Because of this, it recently created the "PACCAR India Technical Center", which has been taking on more and more work. Employees are in agreement that the majority of IT work will eventually end up in India.
There is probably a lot more that's wrong with the company that I cannot think of at this time. The moral of this story is: Do not work there.