Divorce on the horizon. Should I wait for that new car?

Personally i would wait.  She may be entitled to share the assets and if they are tied up in a car that could be a problem. You wouldn't want to be forced to sell the car at a loss and divide the proceeds.

This is your 225th, reply, and you have been asking questions for over five years.  You are asking for financial advice, and it also has legal implications, so you should speak to a lawyer before doing anything else. It will cost you, of course, but it may save you money in the longer run.  

Do it now. Less money for her. Enjoy your now car.

Because community property laws differ by jurisdiction this would be worth talking to a local lawyer about. As just one example, if you were in my state this new vehicle would be considered joint marital assets and she'd own half of it. But that wouldn't be the case everywhere. 

In MY State and every other State I know all recent transactions will be reviewed by the Judge AND can be reversed.  If there is an allegation that you purchased a vehicle in order to increase your expenses and the Judge agrees, you will pay DEARLY.

You will want your expenses to be as large as they can be so you will pay less.

A new car is a nice distraction but either way depending on the country she may be entitled to 50% of everything. Unless she has her own car in which case you might get to keep the truck. Probably best to see a lawyers advice