Front driveshaft play

[DT400]

I have a vibration in the truck that the dealership has yet to find.
One item I found is the front driveshaft is sloppy at the transfer-case. IMO any play in the drivetrain is unacceptable, so I had the dealer look into it, they checked it then put another '22 F-150 on the lift to compare...and it has about the same slop. this is extremely surprising that this is the design.
My question is does anyone else have front driveshaft slop at the transfer-case or did they just happen to find another bad one to compare mine to?
To be clear this isn't a slight bit of play but quite noticeable I know this is still subjective...

Darrell

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[HammaMan]

Sounds about right. The TC is chain driven and there's backlash in that configuration. Backlash doesn't = vibration though. They should have vibration analyzation tools to pinpoint the frequency and help them zero in on the cause. Has the drive shaft or propeller shaft ever been removed? Those are typically balanced as an entire unit requiring marking positions for proper reinstallation. That's very basic stuff when dealing with such items though -- not to say that it's not missed on reinstall.

 

[DT400]

Sounds about right. The TC is chain driven and there's backlash in that configuration. Backlash doesn't = vibration though. They should have vibration analyzation tools to pinpoint the frequency and help them zero in on the cause. Has the drive shaft or propeller shaft ever been removed? Those are typically balanced as an entire unit requiring marking positions for proper reinstallation. That's very basic stuff when dealing with such items though -- not to say that it's not missed on reinstall.

I know gear/chain all have some amount of backlash to allow for expansion and lubrication when hot.
I guess I wasn't clear.
This is more like a yoke nut is loose, a front or rear tc front output shaft bearing loose/worn, worn splines, or a bad U-joint or CV.
These shafts have a boot that covers the entire joint and connection to the TC so I can't tell exactly where the play is.

So far they've rebuilt the front diff, replaced the rear DS, replaced the torque converter then the TC and trans and run the vibration analyzers. Not to mention the other items they've had to replace because they damaged them while doing all this work.

They ran the vibration analyzers on it but only on the lift which is useless since I told them it doesn't really do it until you put good torque on the driveline and is almost nonexistent during a neutral torque condition and somewhat noticeable under decel.

Now their replacing the harmonic balancer for God only knows why...next will probably be the headlights......

Is this slop normal?

To me this has every sign of a worn pinion bearing..likely the inner.

If it is it's awfully strange, but new vehicles have some strange engineering compared to the trucks/cars equipment I've been wrenching on for the last 40+ yrs and I'm just not sure.

If one of my other trucks was this bad they would be pulled from service until the issue could be resolved.

Darrell

 

[HammaMan]

I mean there's backlash in the spider gears in the diff, the ring to pinion, the spider to axle point (shouldn't be much if any, but not impossible as it's not as tight as the axle/hub point), the CV joints (2 per axle), the shaft to axle hub should be tight. Lots of little points adding up to at least the TC chain resulting in several degrees of rotation to and fro.

I can't believe they went to town replacing items without first doing vibration analysis. Could have been something as dumb as a bent wheel / tire out of spec. Had they got the original frequency of the vibration it would have significantly lowered the number of possibilities due to the variance in speed between engine / trans / drive shafts / and axles.

 

[Murrk847]

Can you post a video of what you are talking about? Ill check mine.

If I had to guess, it has something to do to smooth the transition to 4wd.

 

[DT400]

I mean there's backlash in the spider gears in the diff, the ring to pinion, the spider to axle point (shouldn't be much if any, but not impossible as it's not as tight as the axle/hub point), the CV joints (2 per axle), the shaft to axle hub should be tight. Lots of little points adding up to at least the TC chain resulting in several degrees of rotation to and fro.

I can't believe they went to town replacing items without first doing vibration analysis. Could have been something as dumb as a bent wheel / tire out of spec. Had they got the original frequency of the vibration it would have significantly lowered the number of possibilities due to the variance in speed between engine / trans / drive shafts / and axles.

All the things you mention typically show up as rotation backlash in nature...sure in the right instance rotational can morph into lateral due to centerlines changing but not in this case and it's on the other end of the driveshaft
It isn't a tire or wheel as the frequency of the vibration is higher than a tire/wheel and variable based on torque load.

I think the problem these days is we don't have mechanics any longer...you know someone who can think through an issue and come up with logical probabilities. These days everyone just plugs in a computer and replaces the part and hopes that fixes it. But no one is able to troubleshoot beyond that.

Darrell

 

[SALEEN961]

Up and down play in the front driveshaft where it connects to the transfer case is normal. I didn't measure the play on mine, but it feels like roughly 0.030" of free play if you were to check with a dial indicator at the CV joint. My truck has no vibration all the way up to the speed limiter and it's perfectly smooth under heavy loads.

If you're up for the hassle of doing some vibration testing on your own, I'd be happy to give you some guidance on how I use my phone and the Spectroid app to identify the root cause of different noises and vibrations. It won't pinpoint a specific component, but it can help to significantly shorten the list of possible causes.

 

[fordtruckman2003]

Tons of posts on gas pedal vibration if that is what you are experiencing.

 

[WhiteLightningnshitshadow]

Hey Darrell, is it only between certain speeds? Is it only at throttle tip in? Or is it more pronounced under load? Does it sound like its coming from the back?

I, like many, have vibration issues. At least with my truck (2.7 ccsb fx4 3k miles), I have an oscillation around 50-60mph like clockwork when at tip in or accelerating lightly. My theory is this is originating with the rear pinion. The springs are tiny in this truck and I theorize this leads to more axle wrap than other trucks. My pinion offset is 2.5 ish degrees down compared to the trans. If I'm really on it or have a load, the vibration either disappears or seems to hard to notice possibly because I'm asking the motor to make more noise. More likely, the pinion is now "wrapped" into alignment with the transmission when under significant load. I *think* Ford gives us these trucks with pinion angles that compensate. Coupled with the inexcusably ridiculous rake, Ford must be thinking we use the shit out of these trucks.

 

[johnhbrandon]

I know gear/chain all have some amount of backlash to allow for expansion and lubrication when hot.
I guess I wasn't clear.
This is more like a yoke nut is loose, a front or rear tc front output shaft bearing loose/worn, worn splines, or a bad U-joint or CV.
These shafts have a boot that covers the entire joint and connection to the TC so I can't tell exactly where the play is.

So far they've rebuilt the front diff, replaced the rear DS, replaced the torque converter then the TC and trans and run the vibration analyzers. Not to mention the other items they've had to replace because they damaged them while doing all this work.

They ran the vibration analyzers on it but only on the lift which is useless since I told them it doesn't really do it until you put good torque on the driveline and is almost nonexistent during a neutral torque condition and somewhat noticeable under decel.

Now their replacing the harmonic balancer for God only knows why...next will probably be the headlights......

Is this slop normal?

To me this has every sign of a worn pinion bearing..likely the inner.

If it is it's awfully strange, but new vehicles have some strange engineering compared to the trucks/cars equipment I've been wrenching on for the last 40+ yrs and I'm just not sure.

If one of my other trucks was this bad they would be pulled from service until the issue could be resolved.

Darrell

Hey Darrel, I have an MY22 also and have not noticed any odd vibrations. Mine is a 3.5 Ecoboost 4 X 4. I did not see what engine yours has. Can you elaborate? Also, what wheels and type and brand tires are installed on your truck?

 

[3Ranger11]

I have a vibration in the truck that the dealership has yet to find.
One item I found is the front driveshaft is sloppy at the transfer-case. IMO any play in the drivetrain is unacceptable, so I had the dealer look into it, they checked it then put another '22 F-150 on the lift to compare...and it has about the same slop. this is extremely surprising that this is the design.
My question is does anyone else have front driveshaft slop at the transfer-case or did they just happen to find another bad one to compare mine to?
To be clear this isn't a slight bit of play but quite noticeable I know this is still subjective...

Darrell

How much play are you talking about? Keep in mind that when it is in 2WD, the front hubs are disconnected and the TC is not engaged, so it should be quite possible to have play in the front driveshaft. Put it in 4WD and see if there is play then.

 

[HammaMan]

How much play are you talking about? Keep in mind that when it is in 2WD, the front hubs are disconnected and the TC is not engaged, so it should be quite possible to have play in the front driveshaft. Put it in 4WD and see if there is play then.

22+ models w/ TOD transfer case have the front axles always engaged with no disconnect means. Lariat, Limited, and Platinum models from 22 and up are always spinning the prop shaft due to the always-connected approach now employed.

 

[scott011422]

I have a 22" 502A PB. I have an odd vibration under load with or without the ICE running. I have spent a fair amount of time up front looking at things. There is so so so much slop in the front drivetrain. jack up the front end and check the wheel slop. Its horrible!. I haven't had any luck on finding the source of the vibration. I've thermal imaged all the front bearings and such with no luck. Mine is a oscillating warbling noise not unlike the cabin noise of a bomber in a WWII movie. Driving uphill really gets it singing. You can also just hear it rolling down the road with the engine off sometimes. I definitely think its sounds like a bearing.

 

[3Ranger11]

22+ models w/ TOD transfer case have the front axles always engaged with no disconnect means. Lariat, Limited, and Platinum models from 22 and up are always spinning the prop shaft due to the always-connected approach now employed.

I had heard some of the guys saying that about their 2022s. I wonder if they ever went back to the EIWEs on the 23s since the chip shortage is over. Good point, though. I overlooked the fact that he said it was a 502a.

 

[DT400]

Up and down play in the front driveshaft where it connects to the transfer case is normal. I didn't measure the play on mine, but it feels like roughly 0.030" of free play if you were to check with a dial indicator at the CV joint. My truck has no vibration all the way up to the speed limiter and it's perfectly smooth under heavy loads.

If you're up for the hassle of doing some vibration testing on your own, I'd be happy to give you some guidance on how I use my phone and the Spectroid app to identify the root cause of different noises and vibrations. It won't pinpoint a specific component, but it can help to significantly shorten the list of possible causes.

OK so it seems the play is normal...odd but I guess it's engineered that way.
The play I have is similar....I haven't put a dial on mine either.
I know this isn't the cause of my vibration during acceleration but wanted another opinion, other than the dealers, as to it's legitimacy.
I'll have to look into the app...Seems the dealer can't do it so I will.

Darrell

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