Shaking with front hubs locked

[chuckles1856]

Greetings,

Well if it's not one thing it's another. I get the Broncdildo running again just in time for some snow. I lock the hubs and put in 4WD and it shaking pretty bad as I start moving. It continues to shake while I'm driving. I'm trying to isolate so I dis-engage the 4WD and leave the front hubs locked. Still shakes. Unlock the hubs and the shakes go away. Gotta be something with the front hubs being locked?

I tried to find some articles here and I couldn't find any that specifically pin pointed the problem but it sounds like driveline bind?

Thoughts?

 

[Bully Bob]

Jack it up fr. the pumpkin so as both wheels are off the ground.

Put T-case in neutral.., lock one hub & start spinn'n the wheel.. then do other side if needed...then lock-in both sides if needed.

The prob. should jump out at you. i.e. axle., u-joint., hub., or dr. shaft...or maybe the T-case output shaft bearing.

 

[chuckles1856]

Ok so it looks like it fooled me. If you have it in 4WD with hubs locked it shakes. If you take it out of 4WD and keep the hubs locked it shakes for a block or two and then stops. If you only lock the hubs before you start moving there is no shake.

Bully Bob -- when I jacked up the front end ( both tires off the ground), I lock one hub and turn that wheel I see the axel move all the way across to the other wheel. This happens on both sides. If I turn the driveshaft from the T-case I see the axels move but not the wheels. This seems odd as I would think the wheel with the hub locked would turn?

If I lock both hubs I can turn the driveshaft and both wheels move.

Nothing seems to jump out at me but then again I'm not too sure I know what I'm looking for.

 

[Bully Bob]

Sounds like it's OK ...there is no clunking or noise.....

Try turning the (steering) wheels one way & the other... spin the dr. shaft with hubs locked.

Listen to see if there's any noise at the wheel u-joints.

There is a bearing right behind the u-joint. You can lightly pry around that u-joint to see if it moves up & down.

I'm assuming that's a IFS front axle....Someone else will have to chime in as I have limited knowledge of those & elect. shifters.

It's poss. the prob. isn't "jumping out" W/O the weight on the wheels.

Could be a T-case issue as well....or the shifter unit.

Best I can do.... /emoticons/[email protected] 2x" width="20" height="20" />

 

[miesk5]

yo,

I have some eye floaters bothering me again... it's clearing up, but slowly..which will be ok! so, without trying to read thru all what you and Bob discussed...

so,

Operational Test;

"...To CHECK FOR PROPER ENGAGEMENT, dial both hubs to LOCK and raise the front left corner of the vehicle off the ground. Spin the lifted tire. The drive line will turn if the Hub is engaging properly.

TO CHECK FOR PROPER DISENGAGEMENT, dial the lifted wheel hub into FREE and spin the lifted wheel. If the drive line does not turn AND you hear NO ratcheting sounds, the hub is disengaging properly. Repeat step 5- 6 with the right wheel & hub. NOTE: The hubs are not required to seat against the wheel housing when installed, they may move in and out quite easily. This “float” is normal and will not affect performance..." Source: by Warn®

Operational Test; "... (engine off, hubs disengaged), crawl under the truck with the transfer case in 2HI, you should be able to grab the front drive shaft and turn it by hand. Also with the hubs disengaged you should see the front axles turning freely. Now engage the hubs and you should not be able to turn the drive shaft by hand. Jack the front wheels off the ground with the hubs engaged, turn the drive shaft by hand, the wheels should turn. The 4x4 light should not be on in 2HI, when in 4LOW you may have a low range light on, (not all trucks have that light) at least mine doesn't..."

Source: by Seabronc (Rosie, Fred W) at Ford Bronco Zone Forums

 

[chuckles1856]

I just thought of something...I've got different tires on the front than I do in the back. I don't believe they are much different, if any, but reading through some of the links about the front and rear axel spinning at the same rate made me think that maybe that could be the issue?

 

[Bully Bob]

Ahhh., that would be a problem (different size) NOT a good thing...!! [-X

Especially on hard surface.

 

[nelbur]

I'm not sure what you mean by shaking, but if your front drive shaft has not turned for awhile, there could be a build up of dirt on the top which can throw it's balance off, making the truck vibrate when ever the front drive shaft is turning. Clean the front drive shaft and see if the "shaking" is still there.

 

[Seabronc]

I just thought of something...I've got different tires on the front than I do in the back. I don't believe they are much different, if any, but reading through some of the links about the front and rear axel spinning at the same rate made me think that maybe that could be the issue?

That also brings up the possibility of the gearing being mismatched between the front and rear differentials. You might want to lift the wheels off the ground and do a rough check of the gears by turning the wheel while counting the number of turns of the drive shaft per one wheel revolution.

Good luck,

>-

 

[miesk5]

yo

I agree w/Seabronc on tire differences; so does Ford;

Tire Diameter/Circumference & Air Pressure Differences; "...You will recall that at the beginning of this section, we mentioned that we had made sure that all four tires on our truck were the same size, were worn the same amount, were inflated to the specified pressure and were subjected to reasonable loading. Avoiding driveline windup was the reason for this. Figure 18A shows that tires of even slightly different size roll different distances every revolution. Figure 18B shows that the same effect is true for tires that are the same size but inflated or loaded differently. Operating a 4 x 4 in 4WD with tires of different size or inflation will produce driveline windup, even when driving straight ahead! If the vehicle is being driven in 4WD on dry, hard pavement, the driver will notice drag and may experience the hop, skip, bounce effect as the front or rear wheels release the windup..." in Four Wheel Drive (4X4) General Information, Operation & Troubleshooting TSB 92-1-8 for Bronco, F Series & Ranger (COMPLETE); Includes Electric Shift On The Fly (ESOF) Troubleshooting & Hub Operation Source: by Ford via Chilton

as well does Tire Rack;

Tire Circumference Differences; "...The ability of four-wheel drive and all-wheel drive vehicles to divide the engine's horsepower between its four tires is especially useful on loose or slippery surfaces such as sand and dirt, as well as on wet, icy or snow-covered roads. However it's important to remember that in order to transfer this extra power, the four-wheel drive and all-wheel drive vehicle's driveline mechanically connects the tires so they work in unison. Four-wheel drive and all-wheel drive vehicles are equipped with additional differentials and/or viscous couplings that are designed to allow momentary differences in wheel speeds when the vehicle turns a corner or temporarily spins a tire. However, if the differentials or viscous couplings are forced to operate 100% of the time because of mismatched tires, they will experience excessive heat and unwarranted wear until they fail. This necessitates that four-wheel drive and all-wheel drive vehicles use tires that are very closely matched. This is because different diameter tires roll a different number of times each mile as a result of the variations in their circumferences. Tire diameter variations can be caused by accidentally using different sized tires, tires with different tread designs, tires made by different manufacturers, different inflation pressures or even tires worn to different tread depths. As an example of different tire diameters resulting from tires worn to different tread depths, we'll compare two 225/45R17-sized tires, a new tire with its original tread depth of 10/32-inch and a second tire worn to 8/32-inch of remaining tread depth. The new 225/45R17-sized tire has a calculated diameter of 24.97", a circumference of 78.44" and will roll 835 times each mile. The same tire worn to 8/32-inch of remaining tread depth is calculated to be 1/8" shorter with a diameter of 24.84", have a circumference of 78.04" and will roll 839 times per mile. While the difference of 1/8" in overall diameter doesn't seem excessive, the resulting 4 revolutions per mile difference can place a continuous strain on the tires and vehicle's driveline. Obviously, the greater the difference in the tires' circumferences, the greater the resulting strain. This makes maintaining the vehicle manufacturer's recommended tire inflation pressures and using "matched" tires on all wheel positions necessary procedures to reduce strain on the vehicle's driveline. Using "matched" tires means all four tires are the same brand, design and tread depth. Mixing tire brands, tread designs and tread depths may cause components in the vehicle's driveline to fail. Mismatched tires or using improper inflation pressures for all-wheel drive and four-wheel drive vehicles can also result in immediate drivability problems. Some Control Trac equipped vehicles in 4Auto mode may exhibit a shutter on acceleration and/or a noise from the front driveline and transfer case while driving. Some all-wheel drive and four-wheel drive vehicles may exhibit axle windup or binding while driving. Some four-wheel drive vehicles (manual or electronic shift) with a two-wheel drive mode may refuse to shift "on the fly" into 4x4 Auto or 4x4 High at highway speeds..." read more, esp. Matching Tires By Shaving Them to Maintain Equivalent Tire Tread Source: by tirerack.com

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A next Q back to you is what Make, brand and size tires do you have on front and on rear?I have a list of 32x11.50R15's in my site w/manufacturer's Listed OD's @ http://www.broncolinks.com/index.php?index=376

such as Dunlop RADIAL MUD ROVER 32X11.50R15LT; 31.5" Overall Diameter; 11.4" Section Width; $170.55 JAN 2011

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btw chuckles, Have you had time to do those hub checks yet?

Have to begin with that and tire pressures/diameters

after that is a list..

 

[nelbur]

He says that the shaking happens even in 2WD with the hubs locked. That rules out different tires front to back, and different gearing front to back. He also says it stops if he unlocks the hubs in 2WD. That says to me that it is a front drive shaft problem, or a problem with the front u joints.

Clean the drive shaft and go for a ride. I'll bet that will solve the problem. If not look at the front U joints. I have had the same problem when the snow comes and I have not used 4WD since summer. Dirt setting on one side of the drive shaft throws it way out of balance. I hate to start looking for complicated stuff until the simple stuff has been checked out.

 

[miesk5]

yo, Correct, he said that shaking occurs even in in 2WD with the hubs locked

in 2WD & when the front hubs are locked the front wheels ado Not turn independently of the rear wheels if he has a Xfer case issue

 

[chuckles1856]

Thanks so much for all the help with this! I think I may have confused everybody.

Here's what I tried:

1) Locked the front hubs, started the truck, drove around. Result: No Shake

2) With the front hubs locked, put in 4WD (push button on dash), drove around. -- Result: Shake

3) With the front hubs locked, took out of 4WD (push button on dash), drove around. -- Result: Shake only for a block then quits

Miesk5 -- I did the hub checks and everything appears to be functioning as specified.

I never paid much attention to tires before this so I had to go and check everything.

Back Tires: 265/75 R16

Front Tires: 245/75 R16

I'm sure everyone knows this but the first number e.g. 265 is the width. Second number is a percent of the first and is the radius/height of the tire. Of course the R16 is the size of the rim it fits.

I cheaped out buying tires last time cause the front tires were wearing on the inside. Guys at the tire shop said I needed ball joints so I didn't want to buy a set of new tires and destroy them. And Didn't want to buy a $300 pair of new tires. So the guy had some used BF KO's he sold me for $150 (which looked new) and put those on the back. So, now I'm in this stupid situation. While I had the front end up I tried to see if there was a lot of play in the front wheels to indicate worn out ball joints. All seems pretty tight, no jiggling around or loose feeling wheels?

Anyway, I'm going to start looking around for some 265/75's to at least get me through the winter.

 

[Krafty]

that little difference in the numbers can make for a substantial difference in size. for example a 275/60R15 is 1/4 of an inch taller than a 235/75R15 with 4 cm and 15% difference, now consider the 2cm difference with the same percentage.

lets say we do the math.

245 in inches is 9.6, and 75% of that is 7.2 for your side wall, side wall plus rim plus sidewall = 30.4 inches

265 in inches is 10.4, and 75% of that is 7.8 for your sidewall, same plus same, plus same = 31.6 inches

now we use our favorite desert Pie and we get

245/75R16 = 30.4 * 3.14 = 95.5" traveled in one rotation

265/75R16 = 31.6 * 3.14 = 99.2" traveled in one rotation

that is where your shake is coming from. your front tires are being pushed an extra 4 inches in every rotation by your back tires.