Engine knock on startup

[2deuce]

My son is driving one of my M1009's and let the oil level fall to 2 quarts low. After bringing the level up to full, there is a rod knocking noise, about 4 or 5 knocks until oil pressure is present on startup. Then everything sounds normal. Sounds like a dry start up, but I haven't noticed this before on our other CUCV's and we wouldn't have noticed it on this one if the hood wasn't up as the noise in the cab from starting masks the hollow thumping sound. So it may have been doing this all along and we just noticed it as I was in front of the truck with the hood up this time. The other issue is there is no fast idle so it runs slow when 1st started unless I give it some pedal as it cranks and then it rev higher than I like. The fast idle may be masking this on my other CUCV's, but I'm not noticing a dry start knock on them.
What have you noticed on your trucks?
and are there any options to counter this?
The truck has about 130k on it and I"m afraid this could shorten engine life if ignored.

Thanks

 

[cucvrus]

I would not think that 2 quarts low would do any damage. That still leaves 5 qts in the system. I have put 2 quarts in a plow truck on occasion and have had no ill effects. They are still running. I would think you may be hearing things that are different in everyone of these engines. That is my opinion if it matters any fine if not fine also. I think they are a lot tougher than that.

 

[2deuce]

I agree that these trucks are tough and no 2 sound alike and some run smoother than others, but this one gives a definite dry start like a deuce. That hollow knock until the oil hits the bearings is not comforting. As far as opinions go, I appreciate them all!
Thanks

 

[dmetalmiki]

If there is excessive wear in the bearings, they will clatter until the oil pressure flows into them. and gets up to full pressure. An oil pressure check with a quality mechanical guage would give you an indication if the oil pressure is low when running normally. And if so (and in any case) A new set of shells would probably stop any further damage. (as) when they do go, they tend to go suddenly.

 

[CUCVLOVER]

A video might help.
Or if might not, can't hurt though.