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2002 chevy trailblazer_ls
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Discussion Starter #1
So after having changed front wheel bearings and CV shaft/assemblies along with the seals my wife's TB started making noise/vibrating a month of so later. I checked all the new stuff, installed it all myself, and everything was fine. Only thing I can think of is when I did the passenger side CV shaft and oil seal, I pulled the oil seal from the intermediate shaft housing to find what looked like a bit of dried up/burnt grease siting in the cup behind it and the bearing looking like it was pretty dry... I was under the impression that this was lubricated same as the driver side by the diff. gear oil but if it was, none is getting through and I couldn't see any way that it was supposed to.
I looked in the GM service manual and it didn't say anything either way. After installing the new seal and before putting the new shaft in, I poured a bit of gear oil into the bearing cup (it was after midnight, I didn't care anymore) and put it back together.
So now this noise/vibration has moved to the extreme and I'm thinking about that bearing again. Anyone have any idea, is it lubricated by the gear oil or should it be greased? I'm praying it's only that cause the sound and vibration is so bad now I'm hoping it isn't the differential.

Before you ask, yes the diff fluid level is full and was changed within the last year with high quality synthetic fluid.
 

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...is it lubricated by the gear oil or should it be greased? I'm praying it's only that cause the sound and vibration is so bad now I'm hoping it isn't the differential.
Are you talking about the assembly bolted to the passenger side of the oil pan that has an elctrical harness on it? No oil goes to that bearing. The differential is sealed. It does take grease. I would suggest taking that assembly out, cleaning it thoroughly and greaseing it.
 

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Discussion Starter #4
Are you talking about the assembly bolted to the passenger side of the oil pan that has an elctrical harness on it? No oil goes to that bearing. The differential is sealed. It does take grease. I would suggest taking that assembly out, cleaning it thoroughly and greaseing it.
That's exactly what I'm talking about. Kinda figured it out since the schematic shows a shaft seal on both sides of the oil pan.

Thanks.
 

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A common problem getting far more common as the vehicles age. Expensive to get parts from GM, but we have member here from Dorman who's investigating offering aftermarket replacements like they already have for control arms, fan clutches, and many other parts.

GM really blew the design. No diff oil for lubrication. No zerks. And only loaded at assembly time with grease. No mention of needing to regrease them during the vehicle's lifetime, but we have had some reports of them dying before 100K miles.

I'm certainly recommending people remove them at 100K and regrease them, same time they change the differential oil. Transfer case should be serviced every 50K per the Owner's Manual.
 

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I'm about to change the fluid in my transfer case (as well as half-shafts) this week. This bearing that I should grease is obvious when seen? I'm unclear on what you guys are talking about, but I have a feeling I'll understand when I get in there.

thanks.
EDIT: I'm sorry, I missed "Intermediate Shaft bearing" in the title of the thread. In the service manual I found instructions for replacing it, but not servicing it (just as Roadie said). It does say: "Pack the cavity of the inner intermediate shaft bearing housing with 55-65 cc (1.86-2.20 oz) of grease, GM P/N 12377985 or equivalent. Install the intermediate shaft bearing plug. "
So I should repack it with grease while I'm in there? Or are you saying to completely tear down the Intermediate Shaft Bearing Assembly then clean, rebuild and regrease?
 

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Discussion Starter #7
I'm about to change the fluid in my transfer case (as well as half-shafts) this week. This bearing that I should grease is obvious when seen? I'm unclear on what you guys are talking about, but I have a feeling I'll understand when I get in there.

thanks.

I'm in the midst of it now, I'll take some pics and post them here.
 

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It's the assembly on the passenger side of the oil pan where the right side CV shaft click into. Also where the front axle disconnect actuator bolts to. Assembly #56 in this exploded drwg. (Discussed in many other threads you can find in a search.)

 

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Also if you replaced the seal on the drives side of the diff, then you got the seal with the teeth right? because that is what adjusts the preload on are front carrier in the diff if you dont set the seal right the nut can spin loose then the carrier can "Float" back and forth in the diff causing a bad vibration in the front end. just my :m2:

--joel
 

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Ok, I've had a vibration that I originally thought was the right front wheel bearing. I replaced the wheel bearing a while back and the vibration/sound remained. My CV joints let some grease out of the inner boots by the clamp, so I assumed it must be a CV going bad (no, it's not raised)... I just got the right front half-shaft off and the inboard CV bearings still had plenty of grease even though a good bit was slung all around it. the bearings look and spin perfectly and the "tripot" socket looks and feels like new too. arrrrrg.

So I'm trying to get the intermediate shaft bearing assembly off now to inspect it. I have removed the four mounting bolts and left the four that hold the case halves together. I think it should come off, but it sees to be stuck! I need some advise on how to get it off. Once I do get it off, will it be totally obvious if the bearing is bad?

I'm very frustrated that I can't seem to find this horrible sound/vibration and it's so bad that it feels very risky to get over 60mph at this point. Need some direction from my TrailVoy friends!!

thanks!

PS. my mechanic friend suggested that I may have misjudged the side that the noise was coming from... He told me to grab the opposite wheel (with it off the ground) and shake it to check that wheel bearing. I believe it feels fine, but I don't know how much play a bad bearing would have.
 

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... I don't know how much play a bad bearing would have.
I had one with no play and didn't feel bad when in the air, but when the weight of the vehicle was on it, the noise was horrible. And I misdiagnosed which was the bad side because it didn't do the typical "make more noise when it's on the outside of the turn" thing. Thought I'd never misdiagnose something like that, but I did. :eek:
 

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Discussion Starter #12 (Edited)
Ok, I've had a vibration that I originally thought was the right front wheel bearing. I replaced the wheel bearing a while back and the vibration/sound remained. My CV joints let some grease out of the inner boots by the clamp, so I assumed it must be a CV going bad (no, it's not raised)... I just got the right front half-shaft off and the inboard CV bearings still had plenty of grease even though a good bit was slung all around it. the bearings look and spin perfectly and the "tripot" socket looks and feels like new too. arrrrrg.

So I'm trying to get the intermediate shaft bearing assembly off now to inspect it. I have removed the four mounting bolts and left the four that hold the case halves together. I think it should come off, but it sees to be stuck! I need some advise on how to get it off. Once I do get it off, will it be totally obvious if the bearing is bad?

I'm very frustrated that I can't seem to find this horrible sound/vibration and it's so bad that it feels very risky to get over 60mph at this point. Need some direction from my TrailVoy friends!!

thanks!

PS. my mechanic friend suggested that I may have misjudged the side that the noise was coming from... He told me to grab the opposite wheel (with it off the ground) and shake it to check that wheel bearing. I believe it feels fine, but I don't know how much play a bad bearing would have.

First, the shaft housing is mounted with six bolts, not four. The two that open it up aren't visible until you have it off and remove it and the actuator. But if you have the CV shaft out you can see and touch the bearings your interested in.
That aside, I can almost guarantee that if you only replaced one wheel bearing, your vibration is coming from the other. Thats what it turned out to be with mine. It felt fine at the time I replaced the drivers side but it was bad just the same. Even as bad as it had gotten, there was no perceptible play at all. When one goes the other won't be far behind.
 

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That makes me feel a lot better about that mistake! I've looked up to the guy who said to check the other side since I was a kid, it sounds like he's been fooled a time or two as well. Sorry it happened to you too. How did you finally figure out it was the other side?

I was thinking that the intermediate shaft bearing assembly being so stubborn to come off might be a result of heat from the bearing (if it's bad) seizing the intermediate shaft into it... Should it be hard to get the assembly off after the bolts are out?

Thanks a lot Roadie... and of coarse anyone else that may give input.

EDIT: I posted before I saw JerseyWreckDive's post. Thank you sir! I misinterpreted the drawings obviously. I will focus on the other wheel bearing too. I would like some more evidence that it's bad... I hate to replace $100 parts if I'm not too sure. But at the same time, I don't wanna lose time for being stubborn. :)

Thanks a lot guys, I will post the outcome.... I hope.
 

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Discussion Starter #14
Here's a pic of mine when it was out and another with the actuator off, you can see the bolt pattern clearly. It is set into a socket in the pan but a firm yank and a little rocking and mine came right off.
 

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I have taken out all of the bolts except the one hidden behind the actuator. Won't budge at all, no movement whatsoever. I guess it's mallet time?

The fact that it's stuck on so firmly makes me think the bearing is bad in there. But I just know that I'll work for hours to get it off and it will be just fine.... like everything else. I could cry, or put it back together and sell it. :hissy:
 

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I have taken out all of the bolts except the one hidden behind the actuator. Won't budge at all, no movement whatsoever. I guess it's mallet time?

The fact that it's stuck on so firmly makes me think the bearing is bad in there. But I just know that I'll work for hours to get it off and it will be just fine.... like everything else. I could cry, or put it back together and sell it. :hissy:
A couple good taps should do it. :bonk: Not enough room in there to get up a swing that would bust anything. Mine had a fair amount of dirt and grit caked up in the joint, it was wonderful how it all fell down into the receiver as I removed it...:hissy: I'm willing to bet it's fine and you can throw in some fresh grease and be done with it. Get yourself a new bearing tomorrow, maybe a new CV shaft if you have the funds, you already have 95% of the work done and you did say it was throwing grease...

How many miles on yours?
 

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It has less than 80,000 miles.

The noise/vibration started as a problem only when I went around left hand corners at over 40mph or so, and when the suspension was compressed at about the same speeds. Now it makes the noise going straight and it gets worse as I get faster. I can now feel the vibration in my pedal. It still stops completely when the suspension decompresses (like a drop in the road), or I go around a RIGHT hand corner (weight transfers to the left side and off of the right). If I brake from highway speeds, it also amplifies the sound and vibration until the suspension decompresses, or I drop below like 30-40mph.

Why would a part on the left side stop making noise when loaded by turning, then make more noise when loaded by terrain? It seems like it has to be on the right side, by process of elimination. Is it plausible that the replacement bearing I put on the right was bad from the start? Maybe my description will help.

Thanks again.
 

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It's the assembly on the passenger side of the oil pan where the right side CV shaft click into. Also where the front axle disconnect actuator bolts to. Assembly #56 in this exploded drwg. (Discussed in many other threads you can find in a search.)

Roadie, may I ask where you accessed this diagram?
 

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Roadie, may I ask where you accessed this diagram?
I thought everybody knew, but then I assume everybody subscribes to every thread I participate in, which is sort of silly. NOBODY has time to read everything I write except me. :weird:

www.compnine.com is the incredibly useful parts number and exploded drawing resource first discovered by member JKEwing, IIRC.
 

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I thought everybody knew, but then I assume everybody subscribes to every thread I participate in, which is sort of silly. NOBODY has time to read everything I write except me. :weird:

www.compnine.com is the incredibly useful parts number and exploded drawing resource first discovered by member JKEwing, IIRC.
Thank You Sir
 
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