Strong Vibration With Hubs Locked

[NMC_EXP]

Got a chance to try the new M1009 in 4WD thanks to the ice and snow packed roads.

With the hubs locked and in 4-high there is a strong vibration thru the steering wheel and dashboard at 20 to 25 mph. Its shaking hard and I did not go any faster.

I left the hubs locked and put it in 2-high and still had the vibes.

Unlocked the hubs and the vibration stopped.

I have noticed that the right hub has a little resistance when its turned - it feels like it is doing something. The left hub turns real easy, maybe too easy?

Troubleshooting advise would be appreciated. Its too cold and windy around here to be doing unnecessary exploratory surgery.

Best regards,

Jim

 

[Westech]

you replace the front axle U joints? Also check the front drive shaft U joints. Take a look at the bearings also and make sure the ball joints are good. But I bet on the Axle U joints are frozen. I have had to replace every single one on all of my blazers.

 

[NMC_EXP]

Sounds like a good place to start.

Frozen joints a design problem or lack of grease?

Thanks

Jim

 

[Westech]

The fronts are NON greasable from the factory. When you replace them make SURE to get greasable ones.

 

[Recovry4x4]

Or even a bent front drive shaft.

 

[blzrgb]

My guess would be the drive shaft too.
That's the first place I'd look.

 

[NMC_EXP]

Or even a bent front drive shaft.

Bent enough as in a guy could eyeball it, or bent a little so you'd need to check run-out with a dial indicator or some such?

According to the yard man they drove the truck in and parked it....no forklift involved.

Thanks

Jim

 

[4bogginchevys]

I'd bet money it's the front shaft......slip yoke is loose/shaft is bent/ or upper u-joints or cv unit is bad......does it click, that would be the cv flopping around.

I get my drivelines from the junk yard....found many, many good shafts that bolted right in

I commonly get axles at the junkyard aswell, because no one makes as good of an axle joint as spicer used to. Thier new joints are not the same combo of metals and frankly they suck. However if you dont want to swap the axle, and you do end up needing new joints, Duralast Gold is your best bet (autozone), for axle or drivelines. They are now what used to be called BRUTE FORCE a very good joint, I think i've only broken 1, and it wasn't it's fault(bad spindle bearing). They use synthetic grease and may or may not be greasable, I just cant remember. I generally dont want the greaseable axle joints any way because the zerks on most are in the end of the caps and prevent pulling the axle in and out all the time like I do. The synthetic grease is good usually on my u-joints for about 2 years......they spend most of thier time about 2 feet deep in a mucky pond or mudhole though, a commonly driven street truck would undoubtedly be fine forever i'm sure. Good luck with your fixen'!

 

[NMC_EXP]

The fronts are NON greasable from the factory. When you replace them make SURE to get greasable ones.

Bad design.

 

[POOR WHITE BOY]

Front driveshaft problem - either bent ,loose , slip yoke bad or u joint/cv bad on it. Take out the front driveshaft and test drive it:-d

 

[kipman]

I know a guy in Ohio who has brand new front axles with brakes for 250.00.

 

[HardCorps79]

Three main causes of vibration at speed:
Bad U-joints
Out of balance/bent drive shafts
Tire Balance/Wheel alignment

Since you didn't have a problem in 2WD, I'd have to agree with Westy and Recov:
Replace your U-joints ($8-20 each at O'Reilly) and have your front drive shaft checked for balance. Replace if needed.

 

[stampy]

My m1009 rear driveshaft had a crack on the ear that u joint goes in and after driving on the highway for about an hr (feeling an ever so slight vibration and figuring it to be a tire) it broke the ear and proceeded to exit the underside of the truck. I found it about 600 feet behind me on the side of the road. Luckily my front axle pulled me to a nearby wrecking yard and They had a Blazer driveshaft. I also had some friends meeting up with me who helped me put it all back together(thanks again Neilhendrix and Kenny) and I was on my way! So I would get it fixed right away!!!

 

[NMC_EXP]

Three main causes of vibration at speed:
Bad U-joints
Out of balance/bent drive shafts
Tire Balance/Wheel alignment

Since you didn't have a problem in 2WD, I'd have to agree with Westy and Recov:
Replace your U-joints ($8-20 each at O'Reilly) and have your front drive shaft checked for balance. Replace if needed.

(1) Thanks for the info.

(2) I've got to find a hood ornament like yours.

Regards

Jim

 

[Lawrence of Arabia]

Be sure to grease the center yoke between the two u-joints. I replaced all of mine and did not grease the little center ball yoke. When I was driving down the hiway with fronts locked in, the ball socket got hot, disintegrated & grenaded the transfer case. Oh yah and don't drive down the hiway with the fronts locked in. Sure that was the bigger cause of it all.

 

[NMC_EXP]

I know a guy in Ohio who has brand new front axles with brakes for 250.00.

Send me a PM on that when you get time.

Thanks

Jim

 

[rlwm211]

First question....Does the truck have a vibration when the hubs are in and the transfer case is in 2wd?

I had a Suburban with the same front axle and the slip joint on the front driveshaft was worn out and vibrated when the hubs were in and the transfer case was in 2wd. The truck did not have a vibration when it was in 4wd. It eventially got so bad that it vibrated all the time.

You can narrow it down to either the axle shafts or something in one of the hubs by engaging the 4wd and driving without the hubs turned in.

By doing this you eliminate a bad hub from the equation. If get still get the vibration you have to start evaluating the driveline itself. If the vibration is not present you might have a hub that is hung up and not engaging.

I have heard that fork trucks are the favorite tool for relocating this type of vehicle when they are brought in for sale by GL. If yours was picked up in this manner, the front propeller shaft would be most likely bent. The vehcile is very nose heavy so the rear would most likely not be touched by the fork when the vehicle is balanced on a fork truck.

If you want to check for run out on the front shaft, simply use a hammer with a flat top. Set it on its head along side of the driveshaft. I would look for obvious defects like dents and then check for out of round. Spin the driveshaft with your hand and use the hammer handle as a guide to determine if the shaft is moving out of round. Use a large screwdriver and check the U-joints on the driveshaft. You may not be able to flex the u-joint with your hand, but may find it is bad when you try to move the cardan in the bearing cups.

The shaft should turn freely with the hubs out and the transfer case in 2wd. If the drive shaft looks good than someone previously has already pointed out that the axle shafts are most likely the culprit.

Hope this helps.

RL