I own a 1996 silverado with the 5.0L V8 (305) Its got the manual trans. I just recently bought the truck it has 190,000 miles on it I have had it about a month. the syncros in the trannyare suppose to be going out thats what I was told when I bought the truck, (the tranny has a jitter when you start off in1st and reverse,if you dont use the clutch just right, and it grinds going into 2nd if you wind out 1st but not in any other gears) anyways I was told its the syncronizers going in the tranny I was wondering if that were ture or just bull to get the truck to sell??? back to the main topic, I was sitting at a drive through and thought I heard a small knock in the engine when I went to pull to the window I pushed in the clutch and didn't hear it anymore ( being the first time I heard it I rode with the radio off and window up (and down). Then while going down the road I could hear what appeared to sound like a knock maybe in the bottom end of the engine. but you cant hear it unless your driving kind of harsh at low rpms you can't hear this knock. I'm wondering if its the syncros I hear. If it isthe syncros would they going out make these kinds of noise? the truck runs great to have so many miles on it. Its just making me kind of weary to drive it thinking it might have a knock. How can I find out if its a knock or the syncros? Please any help and I'll be deeply greatful...
I live in Bremen, Ga if anyone knows of any local shops that could help me out with this problem please feel free to email me the info @ strick_o_lean@yahoo.com thanks again...

Jeremy
Strickland

 

not sure about the highway noise,but you will get a neutral gear rattle that goes away when you disengage the clutch...especially with 190,000 miles

 

I don't think the miles have a lot to do with it (maybe wrong though) But the neutral gear rattle does go away with the clucth pushed in. But going down the road I noticed today when I shift the rpms stay around the same when I shift, but when I disengage the clutch to shift I no longer hear the noise... IF the engine was the knocking soundI hearI would probably still hear it while I shift, right or wrong, or maybe. Anyways to test this??? but since I can't seem to hear it during a shift it should be the syncros, right? My dad has been a mechanic for over 25 years and he said if its a bottom end knock it'd be albe to hear the knock just idlling not really going down the road. which I was thinking this in the first place, the bottom end knocks are usually caused by bad main bearings right? I was just thinking common since would be if its the mains it'd seemed to knock while its in a low rpm instead of a high rpm. (maybe wrong though) Is there any kind of way to test the enigne for knocks other than by ear??? thanks for your help maybe I can get this worked out.