Ford F150 Rear End Vibration When Turning? 6 Causes And Solutions To Fix It!

Ford F150 Rear End Clunk
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If you are having a Ford F150 truck, then you might have experienced the issue of Ford F150 rear end vibration when turning during driving.

Often this noise and vibration issue appears after the car sits for a longer time and is kept untouched but subsequently it goes away after a decent vehicle mileage.

But if you are experiencing the rear end vibration issue in a Ford F150 vehicle that is regularly taken for a drive, then you need to look for issues in vehicle components.

The Ford F150 rear end vibration when turning is typically due to dry running of the clutch packs and the gears of the LSD differential leading to chattering noise

Any lubrication-enhancing action like adding friction modifier to gear oil, ensuring the quality and quantity of differential gear oil, replacing the worn-out clutch packs and gears, and driving the vehicle in a figure of 8 patterns would help in eliminating this vibration issue.

If you are having the issue of rear end vibration in your Ford F150 when turning, then you are at the right place! Stay tuned for details!

Does Ford F150 Have Limited Slip Differential? How Does It Function?

Many of the Ford F150 truck has LSD (Limited Slip Differential) differential gears at the rear end.

Before we talk about the probable reasons for the rear end vibration issue, it is worthwhile to understand the working and function of LSD.

In the case of a regular open differential gearbox, the left and right-side gears and wheel rotate independently to cater to different wheel speeds while negotiating a right or left turn.

A typical differential gearbox has pinion gear, ring gear, spider gears, and side gears.

The pinion gear is the driving gear that drives the ring gear. Since the spider gears are connected to the ring gear it rotates along with it.

Typically, there are two spider gears used in any LSD. The spider gears in addition to rotation about the ring gear axis, it spins about its own axis when taking a right or left turn.

This spinning of the spider gears about its axis either increases the speed or peripheral velocity of the side gears on one side and reduces the same on the other side depending on whether the vehicle is negotiating a left or right turn, thus ensuring differential wheel speeds.

But consider the case in which one wheel is on high friction surface and the other one is on an oily or a low traction surface.

In that case, the wheel which is on a low traction surface will receive higher power and that side of the wheel will keep on slipping over the low traction surface and the wheel which is on high friction surface will receive less power, and hence the vehicle won’t move.

This is where the LSD comes into the picture, in addition to all the above parts, the LSD has a series of friction and steel plates with clutch pads.

The friction and steel plates together are called clutch packs which are mounted in between the side gear and differential casing.

The side gear has both internal and external splines. The friction plates have internal splines which engage with the external splines on side gear and move with it as a single unit.

The axle shaft with external splines passes through the internal splines of the side gear.

The steel plates with pads have external tabs which fit in the groove provided on the differential casing and hence move together.

When the vehicle runs on a road condition that has a friction surface on one side and an oily surface on the other, the LSD unit ensures that the vehicle takes off from the low friction surface.

During high torque transmission, the spider gears will exert heavy axial thrust force over the side gear whose wheel is on a friction surface.

This pushes the side gears outward and puts pressure on the clutch packs so that the friction and steel plates are locked tightly.

This allows complete engagement between the differential casing and the side gears or axle shafts.

Due to this, the high torque is transferred from the differential casing through the clutch packs to the side gear directly and then to the drive axle and the wheels.

Thus, the wheel which is on high friction surface gets maximum torque and power from the engine and the vehicle manages to move off from the low friction surface.

Since the low friction surface offers low resistance, less power will be transferred on that side.

But in case of negotiating a turn, the spider gear will not exert that much axial thrust force hence the clutch pads will slip over the friction plates which ensures differential speed between the right and left wheels while negotiating a turn.

F150 Rear End Vibration When Turning? Reasons And Solutions To Fix It!

The issue of Ford F150 rear end vibration especially when turning can be attributed to a problem with the rear differential.

Below are the probable reasons and solutions to fix it.

Use friction modifier

A friction modifier is an additive used along with the differential oil to ensure there is limited slip at the interface of the clutch packs with the friction discs while negotiating a turn.

It increases the lubrication between the clutch packs and steel plate and prevents any chattering noise and vibration.

Ford LSD in particular has clutch plate chatter which is why they came up with the friction modifier to enhance the slip slightly.

Make sure that you don’t add too much friction modifier, otherwise, there will be too much slippage between the clutch packs and the friction plates and you may face difficulty driving on low traction roads and surfaces.

Typically, you need to add 4 to 6 ounces of friction modifier to gear oil.

In some cases, the clutch disc swells over some period and it keeps limited-slip engaged and you may observe vibration on turning.

Hence it is essential to add a friction modifier to gear oil to improve slip to avoid rear end vibration when turning in your Ford F150 truck.

Insufficient or wrong Differential gear oil

When we talk about rear end vibration in Ford F150 when turning, it would also be typically due to either insufficient quantity or use of wrong gear oil.

If you have recently replaced the differential oil, then have you ensured the right grade of gear oil as recommended by the Ford?

If not, you need to refill gear oil with good quality and the right grade of gear oil to ensure the smooth performance of the differential gears.

If the differential is only partially filled with oil, the insufficient volume of the oil would cause dry running of the gears and clutch plates.

Hence the clutch packs would not slip as intended against the friction discs when taking turns resulting in vibrating noise in the rear end.

Hence inspect the differential gear oil and replenish it if required.

Worn-out clutch Packs

Often it is the clutch pack that is reported as the culprit for the issue of rear end vibration in your Ford F150 When turning.

 

While taking turns, the clutch plate pads are supposed to limitedly slip against the friction discs to ensure independent speeds of the right and left wheels when turning.

But in case of dry running of the clutch packs due to poor maintenance of the vehicle, the clutch packs would wear out and create chattering noise which is perceived as vibration while transmitting the torque to the drive axle when turning.

Hence it is essential to inspect the clutch packs and replace the clutch plates if found worn out. 

But before you proceed to replace the clutch pack, it is worthwhile to understand the differential clutch pack symptoms to avoid the correct parts getting replaced.

It is better if you know the clutch pack replacement procedure beforehand which involves a complex set of operations with special fixtures to assemble the spring-loaded clutch packs.

Worn-out differential gears teeth

If you are not regularly following the maintenance schedule of the rear differential gear arrangements or topping up oil, then there could be wear and tear of the ring and pinion gears.

This wear would cause too much free play between the ring and pinion gears and thus lead to vibration noise when turning.

If you are a DIY kind of guy, then it is generally easy to check out the condition of differential gear once you remove the differential carrier. So inspect and replace the gears if required.

Change the Driving pattern

Often due to a dry run of the clutch packs you experience rear end vibration in your Ford F150 while turning.

The problem arises when the lubricant oil between the clutch plates tries to escape out.

Without the lubrication, the clutch plates will chatter and cause a vibration when forced to slide against the friction plates.

The clutch packs rapidly stick and release creating this vibration

You can drive the truck in a figure of 8 pattern involving clockwise and anticlockwise movements for about 5 minutes and in the end drive forward for 200 m.

This is the technique that is followed by professional technicians to resolve the chattering or vibration problem in the Ford F150 differential.

This ensures that the clutch plates are forced to open apart and push entry of oil and friction modifier at the interface between the clutch packs and friction plates to ensure lubrication interface and avoid rear end differential vibration.

Carrier bearings adjustment issue

If you have already removed the differential carrier for some reason but while reassembling if the carrier bearings aren’t adjusted right, then when you take the vehicle turn, the outer axle would push a bit on the carrier and this would cause hitting of ring gear over the pinion gear.

This can be confirmed because this would happen only when negotiating a right turn.

This would damage the ring and pinion gear teeth. An oil leak at the pinion gear shaft seal would confirm this issue.

Many bearings are used inside the rear differential gearbox.

If the bearings go bad or it is not adjusted correctly, then you are bound to get the rear end vibration in your Ford F150 when turning.

You need to dismantle the differential housing assembly and properly locate the bearings and adjust or replace the bearings if found bad.

Conclusion

It is quite obvious that the vehicle starts giving out some problems especially after you clock certain mileage owing to the wear and tear involved in many moving components of the transmission.

The Ford F150 truck rear end vibration when turning is typically related to the dry run of the LSD differential gears and clutch packs.

Either adding the friction modifier to the gear oil or replacing the worn-out clutch packs fixes the problem in most cases.

Needless to say, people maintain a sufficient level of the differential gear oil but forget to ensure the correct grade of the gear oil as recommended by the Ford which enhances the differential performance considerably.

The trick of driving the vehicle clockwise and anticlockwise for a few minutes after replacing the gear oil and adding a friction modifier helps to maintain lubrication of the clutch plates to a greater extent and would ensure drastic reduction or elimination of the rear end vibration in your Ford F150 when turning

It’s also a good idea to check the temperature of the differential once or twice while driving if you are pulling a heavy load.

If you see smoke coming off the housing surface, then the components may be already ruined inside.

If it’s too hot to touch with bare hands, it’s got a serious problem inside.

We have tried to collate the root cause for the Ford F150 rear end vibration when turning.

With this information in hand, you may try your hands on your vehicle and save time and a few bucks instead of approaching the service center.

Nothing can be more exciting than analyzing the root cause of the problem and fixing your machine on your own. Isn’t it?

Happy Motoring!

 

References

https://www.f150forum.com/f4/bad-vibration-rear-end-when-turning-stop-286899/

https://www.f150online.com/forums/other-powertrain/367856-vibration-rear-end-while-turning.html

https://www.fordf150.net/forums/viewtopic.php?t=86685

https://cr4.globalspec.com/thread/65957/2010-Ford-F150-4X4-Rear-End-Noise-while-Turning

 

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