Ok this is about to get me down. Little history first, im late 50s have owned no less than 10 vehicles and have never came across what im about to describe. Ive exhaused all my limited mechanic knowledge so here i am at this forum seeking more knowledge. Sorry for being long winded but need to explain some things first. Ok heres the problem...

'03 quad cab, 82k wife owned easy pampered miles, purchased new. Maintanence keep up. Last week she came home, stopped the truck got out, absolutely no probs at this point. Next morning got in turned the key and CLUNK, not a click but a CLUNK and just one with each key turn. No codes showing up.

Ok i get in same clunk, I turn the key back and forth 4-5 times, fires up normally. I take it down the road and ended up going around 25 miles, came back to the house, turned it off and even tried to start it up many times to see what it did, started normally each time. No codes, no knocks, no nothing except start up normally. Ok i think that was strange but whatever it was came unstuck.

Next day, wife gets in, turns the key CLUNK again. Im thinking now this has to be either the starter or battery, replace both, DOESNT change a thing, same CLUNK.

Ok brother in law comes over, fairly good driveway mechanic, always buys and sells cars and repairs them himself. He cleans the battery terminals which were already clean, he takes the starter off thinking misalignment, swaps some relays to rule them out, swaps some fuses to rule them out, nothing, same CLUNK. Ok he takes some voltage readings on battery, fine, alternator, fine, small 12 volt plug on starter fine, postive cable from battery to starter. Ok at the battery hes getting 12.5 volts, at the starter where the cable connects its 10.75 volts. Hmm he and i think, must be the cable with some inside corrosion. He climbs out from underneath the truck thinking he found the prob, i try to start it just for the hell of it and by god it cranks, he looks at me, i look at him, i ask what was the problem, he says i dont know lol.

Ok we try to start it no less than 20 times to see if it acts up again, nothing, starts perfectly every time. Ok the truck is drove normally for the next 4 days, doesnt miss a beat, starts fine each and every time. Wife goes to grocery store, gets in truck, turns the key CLUNK again. Truck was towed back to house where it now sits.

I dont want to call brother in law again and now its headed towards easter and no local garage can look at it until after easter, even dealership cant look at it.

SO ANYONE have any ideas what needs to be checked or ruled out on this truck? Anyone every had anywhere near these kind of symptoms? Appreciate ANY replies.

 

have the battery LOAD tested.(100 amp load). could be a crack inside the battery buss... and ask them to do the test several times...

next time it clunks.. tap the battery with a rubber hammer... not joke.. if starts after .. the battery has a cracked buss.

 

But the battery was replaced and didnt change anything

 

check the starter ring gear on the flywheel... a broken tooth?

the clunk is mechanical.. an at startup... just saying

 

ring gear is fine, no teeth missing. Its like the starter doesnt have the juice to spin the flywheel.

 

I would replace the battery cables (both).... if that does not help.. the starter.

not much left.

 

starter was replaced, no change. Do cables actually go bad?

 

dissimilar metals.. ends are plated and copper wire...
corrosion, oxidation,
and I have seen the strands of copper pop like little fuses in the middle of cable, underneath the insulation.