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Havoc's Questions Post.


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  • 4 weeks later...

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They had those on a bunch of GMs. Its a butterfly in there to keep some back pressure to help warm up the car on cold days. there should be a spring on the shaft that opens it fully when warm. The vacumm hose is to pull it open when you step on it and drive away before it is fully warmed up for the spring to take over.

I think it may have been to help with cold start emissions.

I have removed this crap from engines before and not had any detremental effects.

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Okay I'll look into it thanks Frosty.

And Frosty, did you watch the video? Any thoughts?

Sorry about that Havoc,I am a tad behind. Yeah, you definitely have bearing issues. Get yourself a true GM/Pontiac shop manual (either paper or CD versions). It will outlined the complete disassembly/reassembly instructions and speciality tools required to repair the complete compressor (including the clutch), complete with diagrams. Chilton/Hayes manuals may have most of that info too. I know the GM manuals show everything. I have 2 sets for the Lemans and one for the Trans Am.

Again, I would contact Sears, Summit, or Habor Freight for how to get the speciality compressor tools. It might be easier having your local A/C shop do it - especially since you already have it off the car. You might also have them inspect the entire compressor while they are at it, just a little more piece of mind, in my opinion. Your last option would be to purchase a re-manufactured compressor that may come with a limited warranty.

My Lemans has a similar clutch issue. I hope to get it repaired this spring and re-charge/repair the system.

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  • 2 weeks later...

Okay guys, this is a problem ive had ever since I bought the car, but I don't think I ever talked about it.

Basically, when I'm driving and start to slow down at rate that causes the rear end a good amount a lift, I hear a scraping noise. It sounds almost like something metal is dragging onto the asphalt, but I know nothing is.

I will also hear the noise when I'm not braking, but when the car starts to slow down on a hill (such as engine braking) or when I go off a small incline that causes the suspension to drop.

I'll try to get a video of the noise up later.

Thanks!

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has the rear diff fluid EVER been changed? I would do that for starter, I also would look at all the body bushings, leaf springs, and also if you have the rear sway bar option look at the bushings. there are so many things out back there that could make noise on an old car........ But I would do the rear diff even if thats not making the noise cuz it should be changed out every 5 years or 100k by GM standards. lastly take a look at the drive shaft and make sure thats in good and has the proper lube in its two joints.

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Uhm. I dont think the rear diff fluid has ever been changed. I bought the car with 90k on it and its now at like 110K. I don't know how to change Diff fluid :(

What exactly are the body bushings? and how would I replace them? The leaf springs have rust on them but its all surface. I'm also unsure if I have a rear sway bar. I will take a look at the U-joints for the drive shaft.

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Rear diff fluid is easy....

there is a plug to refill it thats a 1/2 inch socket wrench but you just use the wrench. if you do it yourself youll need to take the diff cover off and replace the gasket. loosen them all a bit like taking off a tire hex pattern. put a bucket under it and let it drain. then take it all the way off. clean off the old gasket and put on a new one and then tighten it all down with a spead wrench an a hex pattern. pour in fluid till its full. how do you know its full the hole you fill it thru it starts seaping out. let it seap out till it stops and put the plug back in with the 1/2 socket wrench. (it also could be a 3/8 size or a 1/2) thats it in a nut shell its actualy pretty easy. if I still lived in MA I could of done it for you. If you cant handle it but I think you can go to some place like Jiffy Lube and they will charge you 90.00 to 130.00 to do it but they have a pump/vac they use and they dont have to take the diff cover off.

youll have to look up the flued it takes, something like GL4 non synthetic or a ful synthetic GL5. my guess is its GL5 75w140 or a GL5 80w90. youll have to look it up.

.............................

Body bushings are the ones in between the body and the frame. they can dry up and make it make a creaking noise or in saver cases make the frame rub on the floor boards /body.

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I don't think it would be the bushings. It i definitely something that is constantly moving, because as the car slows down so does the noise at the same rate.

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Do the rear diff it needs to be don regardless......

if you have any questions PM for my cell # and i'll explain it further.

Also treat the read diff like a tranny just change the fluid if there are metal shavings on the gears LEAVE THE SHAVING ALONE!!!! Dont go poaking around in there and try to clean everything off. ok Its common on rear diff to have shavings in there thats how they wear in and set themselves......

I do this often at work and its easy and teach my people how to do it.

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If the diff fluid has never been drained. Try and get the fill plug off first. Do not drain the rear first. Also check to see if there is a little copper or brass tag off of one of the top bolts on the cover. If it is then the rear maybe a posi and the clutches maybe going bad.

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Yea I should of said make sure you can get the fill plug off first. :lol: kinda like draining the oil out of a car that the hood dosent open. Not a good situation!. :lol:

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I might be a tad bit of cold water. Many of the GM 10-bolt rear ends do not have a drain plug. You drain the diff by putting a catch pan under the diff / diff cover. You loosen the top 2 bolts, and then remove the remain bolts, pry the diff cover over off and let it hang by the top 2 bolts and let the fluid run out of it. Get a new gasket too. Check the bottom of the diff for metal shavings. If there is metal, you might have damage going on.

Now depending on available funds, this would be the ideal time to switch the rear end to a posi-unit or changing the rear end ratio.

Now that the diff is back together and you have installed and torqued down the diff cover, there is a plug at the top of the rear end to add gear lube. You might need to have a manual pump with a hose to push the gear lube into the diff, if the diff is still on the car. If the diff is off the car, you can add the gear lube before you put the diff over back on and put it back in the car.

I am still working on your last video question. I know it is definitely not the EGR valve. You can see the EGR valve in your video, it is the round thing sitcking out of the intake manifold on the passenger side. I suspect what you are asking about is part of the thermatic air induction to help get the engine up to operating temperature more quickly. When the engine is cold, small amount of hot exhaust is sent back north to help warm the incoming air. Engines pollute more when they are stone cold, so the desire is to get the engine warmed up faster by warming up the air intake charge. That's my theory right now. I am looking for a certain illustration to confirm it.

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:D :D :D This diff thing looks like it could be a fun project.

Uhm, what should I do to look up anything I need for my car's diff? Like does it have to be x-body specific or......?

Oh and to add to the last video question, my friend Matt has a truck that his grandfather willed to him when he recently died. Its a 1979 Chevy with a 305 4bbl and he has the EXACT same part in question and I saw how it connects. I'm thinking maybe I should hook it back up?

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I would hook it back up because that valve that it connects to can close and restrict your exhaust.

Does your car still make a clanging noise when you are idling at a stop light?

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Okay! I got a video of the noise AND earlier when I looked under my car I noticed something peculiar. There is an abrasion running the diameter of the drive shaft where it goes by the ends of the mufflers. I looks like the drive shaft was scraping the thick edge of the metal (You know the thicker metal around the edges of the input/output sides?) I'm thinking that this is the noise. I'll upload a video tomorrow

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Here is the noise:

AT 1:29 AND 1:57 YOU CAN HEAR IT!

[youtube]http://www.youtube.com/watch?v=fZjAD_zY2pU

Here is the video of me looking at the abrasion:

[youtube]http://www.youtube.com/watch?v=U0MsOwiHSEY

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Havoc, your driveshaft is definitely coming in contact with one or both of your mufflers. That scrap is fresh and that tells me this probably started when you had your mufflers installed. So whomever installed your mufflers installed them too close to the drive shaft when your rear end travels up and down.

The rubberized brackets you pointed to at the end of your video are stock style muffler/tail pipe brackets. They are used to clamp around the tailpipe to secure it to the chassis and the rubber helps absorb vibrations when the system is under load. I suspect that someone built a custom exhaust and didn't use the stock pipe routings.

I will look for a picture of the lube plug. As I suspected, you do not have a drain plug on your 10-bolt diff cover. You can purchase a new diff cover with a drain plug, but you clearly don't have one yet since you still have a stock cover. So you will have to drain it the way I described above. Depending on how snug it is, you may have to loosen or remove the sway bar to get the cover off completely. You won't know that unless you have a shop manual or you try to take it off and you can't remove it completely with it in the way.

When I installed the 12-bolt in my Lemans, I went to Mosier. They added a diff cover that has a drain plug and bolts that help retain the bearing caps to prevent them from shifting under high torque load.

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That valve that you were talking about not being hooked up maybe the noise as well. My buddies C10 is making the same noise and all we did was mechanics wire that valve open.

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the fill plug should be on the top/side back off the diff. here is a pic to help you out. but yea you def do not have a drain plug just a fill plug.

rear_diff2t.jpg

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