Hey. I bought 2nd truck now. It's 2003 GMC Sierra slt z71 5.3. It's 271,000. Drive good. Just start oil leak due rear main seal. Plan to replace seal. Is there anything I need replace anything new due high mileage on engine?

 

If anything was due, it would have been a long long time ago seeing how the service intervals stop at like 100,000 or when it out of warranty.

Anything past that is what whoever the owner before you did because something was wrong.

So just check over things, like spark plugs and wires condition, coolant condition. The color of the trans fluid and rear diff fluid condition. If the brake fluid looks terrible or fails a brake fluid test strip, flush the fluid out and replace it.

Clean the throttle body and MAF sensors just because that's free to do yourself.

These kind of things.

 

Seeing how you have to pull the transmission to change the rear seal out...

Converter?


Outside of that, everything FFDP listed.

 

Like need new timing chain oil pump etc but it's run good. Only rear seal oil leak that it. All stock motor at most. I'm 2nd owner this now

 

Timing chains and oil pumps are not a maintenance item.

It's really a either they work or they don't type of thing. If you still got good oil pressure, the pump is still doing it's job.

And these timing chains are strong, rarely do they fail. Sure they stretch a little bit but I've never seen or heard of one jumping time. Tons of people have ran these motors to 300-400K without issue this way.

 

Okay thanks for advice. I will do all replace new gaskets and spark plugs. Good to go.