Who they are
Zachary Paul Solomon owns Z and A Diesel LLC in Tulsa. He learned the trade from two mentors right after high school. Over the years he worked his way from apprentice up to owning his own company.
What gets called in most
The most common calls are for engine work. That covers everything from injection pumps to full bottom end jobs. There is no single price for this kind of work.
Zachary says they keep pricing fair. "We are fair and understand that price gouging will get you nowhere," he says.
Where customers get surprised on price
One job trips people up more than most. An engine mounted air compressor replacement is what customers most often get wrong on price. Depending on the engine, it can be a couple hour job or turn into an all day job.
That range in time is why the cost can swing so much from one truck to the next.
A rebuild he stands behind
One job stands out for Zachary. A Series 60 Detroit came in with every gear in the housing broken apart. The customer had been told the engine was junk.
Zachary's shop rebuilt it instead. Almost 25000 miles later, it is still running strong with not a single issue.
Tools and maintenance advice
In the bay is a heavy duty scan tool that runs most OEM tests on class 6 and above commercial vehicles.
Zachary says the maintenance item people skip most is the crank case ventilation filter and PCV valve. Clogged ones blow seals on the engine. He says ignoring it will cost far more money down the line.
Area covered and calling them
Z and A Diesel LLC covers all of northeastern Oklahoma. When you call, Zachary sets up a time to meet and gives you an estimated price for the work before anything starts.
His favorite vehicle he has worked on is a 1974 Kenworth W900A.
Interviewed by MechanicRank · October 28, 2026. Nothing here is sponsored and nothing was rewritten into marketing copy. Read the other features or tell us about your own shop.