Time sensitive question about cv axles, any help appreciated

Blackmar401

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So I am getting a bad vibration when accelerating. Prior to this there was an occasion bang like gears slamming or metal hitting when beginning to drive. From what I read I'm thinking it's the 1st joint on the cv axle. My front driverside cv is covered in grease and oil and has been since I bought it 3 years ago so I'm assuming that is the culprit. However I just realized that when driving in 2wd(always) that it should be the rear wheels engaging and would have to be a rear cv? I am at work and the tahoe is at home so I can't even investigate it until later tonight. My issue is I ordered a FL CV axle yesterday and we are very short on funds so now I'm debating canceling the order hopefully before it goes out or maybe being able to change the order? Any help would be great. Is the tahoe possibly FWD when it 2wd? Could the selector be malfunctioning and its actually in 4wd all the time?
 

George B

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Your Tahoe is rear wheel drive when in 2wd. It is likely that your rear most universal joint in the rear drive shaft is bad. You will need to jack the truck up and check it for play.

If you have a front cv throwing grease you should replace it too.
 

OR VietVet

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Like @George B said, is rear wheel drive when in 2wd. If the front cv axle boot is split it slings grease, that is inside there, thru that split. Is the outer boot or inner boot slinging grease or both? They may not be slinging grease at all and you have an oil leak or fluid leak above it that is dropping on to the axle. It would be hard to believe that a split boot would still be slinging grease for 3 years. Should be dry by now and making a hell of a noise, but you have to remember that it will only sling grease when the axle spins and that does not happen in 2wd/rear wheel drive.

So, the problem is likely the rear driveshaft u-joints, there is no rear "cv", depending on how and where you feel the vibrations. Do you feel the vibes in the steering wheel, seat of the pants or in the floorboard? But based on your description, it does sound like it is a u-joint on the rear driveshaft. If you do one u-joint, do them both. If you have never done u-joints, they need to be phased right, so watch a you tube video or five and go from there or have a qualified friend help or a shop. Good luck and come back here and post results of this diagnosis and work.
 

OR VietVet

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Ok, spins but not under power from the engine, correct? You would think an old fart like me would know this and especially since I own one, but if memory serves, they spin but not under power till auto or 4wd hi or 4wd low is engaged?
 

George B

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Ok, spins but not under power from the engine, correct? You would think an old fart like me would know this and especially since I own one, but if memory serves, they spin but not under power till auto or 4wd hi or 4wd low is engaged?
You are correct. The front drive shaft doesn’t spin but the two cv axles do.
 

OR VietVet

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Oh, ok, I forgot, the axles spin because are splined to the hub but not under power till auto or 4wd is engaged.

Ok, I need to invent a cheap locking hub for these things.

So, @Blackmar401, remember what @George B said and not what I said about the axles spinning. Doh..... :banghead:
 
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Blackmar401

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Like @George B said, is rear wheel drive when in 2wd. If the front cv axle boot is split it slings grease, that is inside there, thru that split. Is the outer boot or inner boot slinging grease or both? They may not be slinging grease at all and you have an oil leak or fluid leak above it that is dropping on to the axle. It would be hard to believe that a split boot would still be slinging grease for 3 years. Should be dry by now and making a hell of a noise, but you have to remember that it will only sling grease when the axle spins and that does not happen in 2wd/rear wheel drive.

So, the problem is likely the rear driveshaft u-joints, there is no rear "cv", depending on how and where you feel the vibrations. Do you feel the vibes in the steering wheel, seat of the pants or in the floorboard? But based on your description, it does sound like it is a u-joint on the rear driveshaft. If you do one u-joint, do them both. If you have never done u-joints, they need to be phased right, so watch a you tube video or five and go from there or have a qualified friend help or a shop. Good luck and come back here and post results of this diagnosis and work.
It started in the petal and steering wheel but after a day it started getting worse to where everything was shaking and my wife could bow feel it in the passenger seat. As soon as you let off the gas it stops. If you drive slow like 20mph you don't feel it. The leak appears to be where the cv bolts to the transmission and constantly looks like fresh oil. Fluids never seems to be low however. I will have to check them tonight
 

OR VietVet

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Does sound like the leak is the seal for the stub shaft for the front drive axle. The other vibes do sound like what @George B said, the rear driveshaft u-joint(s).
 

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