Front Diff/vibration

[SloGN]

Hey guys


I have been fighting trying to find a vibration in my truck. I have installed a new propshaft and done the rear u-joints as well.

The other night i was looking at all the front end componets and noticed that the metal ring on the stub shaft thats located behind the cv flange is loose and i can spin it in my hand. I then noticed that the bolts for the CV shaft was loose. So i proceeded to tighten the bolts back down and went and test drove it and the vibration is worse now. So i'm thinking that the Front diff is in need of a rebuild. It appears the the pass side axle has been replaced as it looks new compared to the drivers side and also the cv flange has some up and down movement there as well

So my question is does anybody rebuild them on a exchange bases? I don't really know anything about setting ring and pinions up and so forth..



TIA

Pat Broughton

 

[TxSy1430]

Re: Front Diff/vibration

Sounds like the bearings are going out. Might be cheaper to get a used one($150). I believe it's several hundred dollars to rebuild.

 

[JSM]

Re: Front Diff/vibration

Our front diff is one of the hardest to rebuild, or so I have read. Basically due to no "cover" and access to read the backlash on the gears.

Once removed they are small enough to ship fairly easy though. 2nd is find a used one $100 or so is what I paid for 1 last time. 4x4 will work, just swap out pass side axle.

randys ring and pinion is a good source for parts, you can probably even ship it to them if you wanted to get redone.

 

[SloGN]

Re: Front Diff/vibration

ok update


I rebalanced all my wheels and tires using a lug cetering method. I replaced the RF cv axle again since the other had some movement in it and thats the one with the loose bolts. I went and had the rear drive shft balanced.

I removed the prop shaft and went fpr a drive and it still vibrates like hell around 65-70 mph. the vibration is so harse that the rear veiw mirror become blurred when looking at it.

I'm going crazy here trying to figured it out.

If the front diff is goning bad wouldn't i feel the vibrations thru the steering wheel since the cv axles are connected to the steering parts?

The Transfer case how can i rule out that it's not the t-case? i changed the fluid in it a few months ago and it didn't smell burnt or anything.

This has been a on go9ing thing since i bought it.


so whats next.

 

[Goshinki]

Re: Front Diff/vibration

I am stuck at the same place you are... I feel I have the same problem...

I am getting my rear drive shaft checked some time this next week...


I replaced my shocks, idler arm, lower ball joints, rims & tires and had them rebalanced...

Also those things needed to be replaced anyways but still didn't fix my issue.



If I get it up to 80 MPH and then get off the gas the vibration cuts in half or more...


The steering wheel doesn't vibrate but it is loose but I believe that is some what normal... until I upgrade it...


But same feeling when I am driving 60 - 70 is horrible 70 - 75 is better 75+ scares me =P

Kinda strange on how it goes up and down...


Some one told me its easy to throw off weights off the drive shaft in these trucks... So that is why I am checking that next...


But how do I check the transfer case... I don't have any poping while turning tightly...

 

[SloGN]

Re: Front Diff/vibration

UPDATE


I jacked the SY up this evening and put it on blocks in the back and jack stands in the front. I was checking somethings and noticed that i could move the driveshaft yoke up and down a pretty good bit so i'm thinking this is the area i need to be looking in. I'm referring to the end that slides up into the T-case. Note that i still had the suspension loaded at ride height while i was checking.


I also ran the truck with all 4 wheels off the ground and i couldn't really see the driveshaft moving but i could feel the T-case vibrate pretty good.


So is the slip yoke on the drive shaft wore out or is the bushing in the tail shaft wore out or maybe a combo of both. I took the T-case out and tore it down to inspect the inner bearings and the output shaft bearing(rear) don't appear to be loose on the shaft. but when i spin the bearing it don't sound very good.

TIA guys

I'm gonna find it :rant:

 

[SloGN]

Re: Front Diff/vibration

Is the tail-shaft bushing still in the extension housing? Often, it will move inwards until it comes out of the extension housing bore, and just flops on the output shaft. You say you have the T-case dis-assembled. If you have removed the extension housing, this should be obvious, if the bushing came out. Try inserting the yoke into the housing, and check for 'play'. It should be snug.

some ideas.

the bushing appears to be in the correct spot and the bushing don't appear to be galded or anything.

 

[SloGN]

Re: Front Diff/vibration

OK. But figure it out. You should not be able to move the yoke 'up and down' in the extension housing.

I saw in an earlier post that you replaced the U-joints. Were they bad. Ie, the bearings were rust-dust, or really messed up? I ask this, as bad U-joints will cause vibrations that cause problems elsewhere. Like extension housing bushings.

The U-joints had rust on them but they felt okay so i decided to replaced them i then had the driveshft rebalanced and it was out of balance on the lower end i guess due to they ground off the factory weight and added another one a tad larger in almost the same spot.


I loaded up the T-case and parts and took them to a friends shop and cleaned everything very good and had him inspeact all my parts and the rear bushing in the extension housing when compared to a new one is really wore out.

My thinking last nite when looking at that bushing those were made like rod bearings where they had copper/bronze under the alum coating so since i didn't see and copper/bronze shwoing i didn't really inspect the bushing very good.

This is my first time every going inside a T-case so with a parts break down i was assuming the output shaft bearing was toast causing the problem. But after further investagation all the parts in the T-case is good with very little wear on anything.

So i replaced the bushing int he tail housing with one from a 2004r buick GN trans as they have the same part # and my buddy keeps buick GN tranny parts in stock.

I reassembled the T-case today and plan installing it back in the truck tomorrow after church.



So guys that read this using the search button another thing to check is the rear tailshaft bushing/driveshaft yoke play up and down movement

 

[SloGN]

Re: Front Diff/vibration

UPDATE


I reinstalled my T-case and went and drove the truck. Some of the vibrations has went away.

I now have a roaring noise coming from the pass side floor board area. So i pulled the pass side wheel bearing and replaced it with a BCA/national unit. One thing i noticed that i can move the stub axle flange back and forth (in/out) quite abit is this normal? is it possible for the stub axle bearings to go bad?

I'm going out of my mind chasing this down.

 

[SloGN]

Re: Front Diff/vibration

OK. Are you referring to the inner flange that the half-shaft bolts to with 6 bolts as the "stub axle flange"?

If so, no, it should not move in and out. If it does, the axle spring-clip is shot. It's been discussed a bunch of times on here. I bought a bunch of them from GM awhile back, and change them if I have an axle out of the front diff. GM P/N 14041989. I think I've read that NAPA also has them. Sometimes NAPA can cross ref the GM #.

bummer is you have to take the RH wheel bearing and knuckle apart again. :rant:

Regards,
Dave

I'm referring to the shaft that is inside the axle tube (with the flange on it) it moves in and out quite a bit.

Now can that axle tube assmbly be removed witht he frint diff still in place?

 

[SloGN]

Re: Front Diff/vibration

UPDATE


Well the truck is now back up in the air :lol: I run the truck on jack stands with the rear drive shaft removed and i still got the vibration/noise @ 65-75 mph. So i then disconnected the propshaft and run the truck with just the transfer case turning and i have no vibrations/noise. So i then reinstalled the rear drive shaft and run the truck up to 65-75 mph and the vibration/noise is gone...............:rant: so i went ahead and pulled the front diff unit out and gonna open it up and inspect the bearings there to see if it has a problem.

 

[synsoup]

Re: Front Diff/vibration

I'm curious to know what it is too. My truck does the same exact thing and if I pull the propshaft the vibration goes away. I've tried a different propshaft but it does the same thing.

 

[Mtn Z]

Re: Front Diff/vibration

UPDATE


Well the truck is now back up in the air :lol: I run the truck on jack stands with the rear drive shaft removed and i still got the vibration/noise @ 65-75 mph. So i then disconnected the propshaft and run the truck with just the transfer case turning and i have no vibrations/noise. So i then reinstalled the rear drive shaft and run the truck up to 65-75 mph and the vibration/noise is gone...............:rant: so i went ahead and pulled the front diff unit out and gonna open it up and inspect the bearings there to see if it has a problem.

Probably just the propshaft. I had the same issues as you did and I swapped to a Gilbert. Problem solved.

 

[cloneman315]

Re: Front Diff/vibration

i think larry had the same problem and it was his propshaft also.

 

[SloGN]

Re: Front Diff/vibration

Probably just the propshaft. I had the same issues as you did and I swapped to a Gilbert. Problem solved.

i think larry had the same problem and it was his propshaft also.

Guys

I have changed the propshaft. I have even drove the truck without the propshaft in there and it still did it.

so buy running it up on the jack stands without the propshaft connected the front wheels can't turn.

Anyhow the bearings don't look real good in the diff so since i have it out it's getting a full rebuild.


if this don't fix it i need somebody else to look at this thing before i f-ing burn it to the ground.

 

[cloneman315]

Re: Front Diff/vibration

haha ah the fun huh ?

 

[SloGN]

Re: Front Diff/vibration

haha ah the fun huh ?

Ya know dude.

This sy has seen more air time on jack stands/lifts than my gn for the last 10 yrs !
I have only owned it since apirl of 08.

When i test drove it. I thought is was either flat spotted tires or they needed balancing but i guess not!

So i'm spending my money tring to fix that instead of buying your sy rims

 

[Mtn Z]

Re: Front Diff/vibration

Ya know dude.

This sy has seen more air time on jack stands/lifts than my gn for the last 10 yrs !
I have only owned it since apirl of 08.

When i test drove it. I thought is was either flat spotted tires or they needed balancing but i guess not!

So i'm spending my money tring to fix that instead of buying your sy rims

That sucks. I was banking on best case scenario with the propshaft. Sorry to hear it's the diff. I have also dealt with jackstand syndrome. I just got my stupid truck back on the road after almost two years out of action. :roll: