Help, Loud engine noise!

[SnowNeck]

Alright, I have a 1985 gmc 4x4 305/7004/208np. I now have a noise that ive spent 2 weeks trying to find and can NOT find it for the life of me. So first i thought it was my alternator bearing so i just bought a 140 amp alternator, put it in and noise is still there. Its a hard noise to describe, almost like a loud chatter,chirping but realllllllly loud when pulling a hill. makes the noise 75% of the time now. only time it doesn't is when traveling on dead flat road and or down hill.I had taken the alternator belt off to see if it was those 3 pullys, still there. Messed with the power steering and doesn't see, to be that either. I'm completely stumped, Ive listen to so many videos an cant really see to find it. Please help. Oh and the belts are newer too.


- Jake

[piecesparts]

Take a look at your engine's flexplate. It sounds like it is cracked. I had this happen on a couple of trucks, so I replaced the flexplate with a heavy duty plate and solved the issue. The noise comes from the torque converter ballooning out when you spin it up to speed. The convertor will spread axially and cause the flexplate to crack.

[Chevy3+3]

Definitely sounds like something tied to your drive train if the noise gets worse when the motor is under a load.

I chased a noise under the hood once. I replaced everything and it was still there. It ended up figuring out that it was the fan clutch. You might check that. They will wobble and chatter when they start to go bad. Grab your fan and see if the fan & shaft wobble any when trying to move it up and down.

[SnowNeck]

Originally Posted by Chevy3+3

Definitely sounds like something tied to your drive train if the noise gets worse when the motor is under a load.

I chased a noise under the hood once. I replaced everything and it was still there. It ended up figuring out that it was the fan clutch. You might check that. They will wobble and chatter when they start to go bad. Grab your fan and see if the fan & shaft wobble any when trying to move it up and down.

Alright funny you say that, this morning for ****s and giggles before i left in it for work i spread down the power steering V belt and pulleys. Got in the truck and drove the noise wasn't there. Peddle to the floor going up hill. it returned when I left work this evening. But its a relief to know its not internal. Now, after reading your post i'm bout to head out side and see if i can wiggle around the fan at all. If that checks out okay, I'm thinking maybe its the pulleys or one of the 3 or just a ****ty belt, which is surprising considering its from napa. What are your thoughts?

[cory d]

can you hear it through the exhaust. you can also use a tube to listen at different parts

[SnowNeck]

Originally Posted by cory d

can you hear it through the exhaust. you can also use a tube to listen at different parts

I can not, but I'll have to use the tube in the future!!!!

[Chevy3+3]

If you sprayed the belts and the noise no longer existed then I would say it has to do with your belts. They can make a racket if worn or not inline with the pulleys correctly. Have you tried tightening your power steering belt? Are you sure its the correct one?

[SnowNeck]

Originally Posted by Chevy3+3

If you sprayed the belts and the noise no longer existed then I would say it has to do with your belts. They can make a racket if worn or not inline with the pulleys correctly. Have you tried tightening your power steering belt? Are you sure its the correct one?

Just checked the fan and there is a lil amount of play in it, but to be completely honest the belts a the correct size, so id say yes there correct one, but the power steering side v belts seems 3x's more rigid than the alternator side v belt, and yes I have a few times now, I have the Power Steering belt pretty much as tight as I could get it. bout a 1/2 inch of play up and down. If I let it be any less, the belt squeals like a pig with the slightest turn. Now as for the pulley alignment, I dont know how to Correctly check that, by eye it looks good and straight.

[SnowNeck]

After taking a second look at it, when I grab the fan clutch to see if it has any play. I noticed when it moves, it's also moving the water pump pulley... what does that mean? Anyone?

-Jake

[Wrecked1982]

maybe a video of the noise would help

[SnowNeck]

Originally Posted by Wrecked1982

maybe a video of the noise would help

I would if my phone wasn't also all broke But, I can describe it. in neutral i can rev it all i want and it will never make the noise, going down a hill or coasting at any speed no noise. But, pulling a hill or any sorta real acceleration i get the noise. The noise reminds me of a few things hah, a mason jar with nuts and bots in it rattling around, dieing pigs, its a real aggressive sound, just watched a YouTube video of a power steering pump with a bad bearing that sounded similar... but I'm honestly stumped, i drive the truck 40-50 miles to school and back ever day with this noise. its been about 3 weeks now and what ever it is hasn't let go. As i said before some belt conditioning helps for a mile or so. Not sure if any of that helps

[79Betty]

My power steering pump SQUEALS like a pig when i really get to turnin. I'm redoing all my steering this summer as my new 11" lift has taken it's toll already... Ram assist here i come!

[jjzepplin]

If belt dressing helps then it is in your belt system. Maybe you have the wrong pulley configuration. Or one is out of alignment. Saw a bent steering pump bracket do this to a guy for years til he figured it out when he switched out the engine.
Although the symptoms sound a bit like the tranny. Why would it make the sound when pulling on a hill?

[Chevy3+3]

Have you tried the belt dressing several times and everytime the noise stops? To me it definitely sounds drive train related. I'm thinking tranny now. Maybe your timing chain has got slack in it? Are either of your motor mounts broke? If so your motor could be pulling up on one side when under a load. The motor mount might be rattling when lifted a little (just a thought).

[SnowNeck]

Originally Posted by Chevy3+3

Have you tried the belt dressing several times and everytime the noise stops? To me it definitely sounds drive train related. I'm thinking tranny now. Maybe your timing chain has got slack in it? Are either of your motor mounts broke? If so your motor could be pulling up on one side when under a load. The motor mount might be rattling when lifted a little (just a thought).

After trying the belt dressing a few times, it indeed has nothing to do with my belts. oh well a new alternator and water pump isnt a bad thing. But now im thinking transfercase. and how would i check my engine mounts??

[74sqrbdy]

On one of your posts you said it sounds like a mason jar with nuts and bots in it rattling around. Could it be pinging or detonating? Under a load like going uphill is when this happens most. Maybe your timing is too far advanced or you got a realy bad batch of gas.....both of these could cause that type of sound.

[SnowNeck]

After looking at the truck all day and romping it around at school found out that the noise is coming from the transfer case. I thought it was the belts because it made less noise when the engine was cold so as it warmed up I thought it was the belt conditioner wearing off when really it was just getting warm. But, I'm not at a loss guess I should starting looking for a new 208 transfer case

[Wrecked1982]

probably not, but does it still has the cathalyc converter? if its from the tc by the sound it makes put your figer in the oil to see if its silver

[SnowNeck]

Originally Posted by Wrecked1982

probably not, but does it still has the cathalyc converter? if its from the tc by the sound it makes put your figer in the oil to see if its silver

Cats are long gone, but right in the oil drain plug?

[Wrecked1982]

take the fill plug out on the tc and put your small finger in and look at the oil if there is still some left, if it sounds like loose shrapnel rolling in there maybe youll see it in the oil color. also put the tc in neutral and shift all the transmission gears maybe youll hear it

[SnowNeck]

Originally Posted by Wrecked1982

take the fill plug out on the tc and put your small finger in and look at the oil if there is still some left, if it sounds like loose shrapnel rolling in there maybe youll see it in the oil color. also put the tc in neutral and shift all the transmission gears maybe youll hear it

Alright, I'll have to do that in the morning. Thanks for all of the responses. Also the noise is almost like a high pitch chirping, along with a bad loose sounding bearing. That's the best way to describe it after hearing it for my self out side the truck. I just dont understand how nothing has broke after a continuous month with this noise, and just how loud and bad it sounds. its louder than my my radio turned up. its insane.
Thanks again.
-Jake

[GM-power]

To check your mount id visually inspect it then have somebody load the engine up. Generally a motor mount will make a clunking sound and itll feel alittle sluggish.

[SnowNeck]

Originally Posted by GM-power

To check your mount id visually inspect it then have somebody load the engine up. Generally a motor mount will make a clunking sound and itll feel alittle sluggish.

Sounds pretty good, and I started to look at it and think about it. And I have a flex pipe that runs right up close behind the transfer case, it's actually woarn down the fins a half inch but not has a quarter inch gap. Now that im thinking about it I bet I have a bad motor mount that is clanking and the engine is torquing and chattering off the T case. Just a hope! Hah

[Chevy3+3]

Best way to check for a bad motor mount yourself is to open the hood and with the truck running. Put it into gear and act as if your going to power brake your truck. While your doing this look through the gap between your hood and cowl. Don't be afraid to give it the gas because you trying to duplicate the same torque when your driving. If your mount is broke the engine will lift up on one side in drive. If it doesn't then try to power brake your truck in reverse to check the other mount.

Its pretty easy to figure it out once you see the motor try and climb out from under the hood, lol.

[SnowNeck]

Originally Posted by Chevy3+3

Best way to check for a bad motor mount yourself is to open the hood and with the truck running. Put it into gear and act as if your going to power brake your truck. While your doing this look through the gap between your hood and cowl. Don't be afraid to give it the gas because you trying to duplicate the same torque when your driving. If your mount is broke the engine will lift up on one side in drive. If it doesn't then try to power brake your truck in reverse to check the other mount.

Its pretty easy to figure it out once you see the motor try and climb out from under the hood, lol.

Hahah I like how easy that sounds to check it. Drive one way reverse the other