Bought my first truck *1989 Peterbilt 379*

Make sure all the clips stabilizing the steel fuel lines from the fuel pump to the injectors are in place and tight. My 91 constantly cracked fuel lines (it was so often i carried brake line, a pipe bender and a flareing tool for road side redneck fixes)till i figured out the previous owner had removed those. If its still got the old style pete air ride look into changing out all over to the pete low ride suspension. The difference in ride comfort and stability is astronomical.

 

An '89 with only 550K on it? How long has it been sitting? That odometer should have turned over a few times already.

 

Telltale sign the odometer has turned over is the very first digit on the left will be offset a bit and won't be lined up perfectly with the rest.

 

I didn't realize they had odometers that went into the millions back then. I thought they only had 6 digits and rolled over ever 999,999km. Unless it was changed out or unhooked its quite possible its legit.

 

It could be that the speedo was replaced. Those early electric speedos were'nt real reliable. I had to resolder a bunch of the connections in my 90.

 

If the seat cushions arent worn out and the fuel pedal hasn't been rubbed smooth there is no reason to suspect the miles aren't real. Not everyone pulls freight so cheap they have to run 150k miles a year. If he worked local its quite possible he did under 30k a year.