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Transmission Driveshaft Rebuild
 
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Pelican Technical Article:

Transmission Driveshaft Rebuild

Nick Czerula

Time:

3 hours3 hrs

Tab:

$10 to $50

Talent:

*****

Tools:

18mm wrench, mallet, puller, bearing separator, flat face snap ring pliers, cutting pliers

Applicable Models:

BMW Z4 Convertible (2003-06)
BMW Z4 Coupe (2006)

Parts Required:

Drive shaft grease, center support bearing

Hot Tip:

Mark position of the driveshaft before remove to reduce the chance of vibration

Performance Gain:

Knocking under acceleration/deceleration

Complementary Modification:

Giubo (flex-disc)

In BMW Z4 models with rear-wheel drive, the driveshaft connects the transmission output shaft at the rear of the transmission to the rear differential.

The job of the driveshaft is to transmit the torque from the transmission and apply it to the rear differential. Being the engine/transmission assembly and the rear differential are rubber mounted and BMW uses a floating differential there needs to be a little bit of flex in the driveshaft. BMW uses a two piece driveshaft with a center bearing supporting the middle of the shaft. This center bearing can wear out over time and you will feel a vibration and noise under severe acceleration and deceleration. Also the driveshaft uses a CV joint at the mounting point for the differential. CV joints can wear over time particularly with hard driving. You can extend the life of your driveshaft by repacking this CV joint with new special grease. In this tech article we will go over all of the steps to rebuild your driveshaft. A universal joint is also used in the driveshaft to allow the angle change at the rear differential. The U-joint bearings can dry out and cause a vibration when worn. If this is your issue, replace the rear section of the driveshaft.

The driveshaft needs to be removed in order to rebuild it although you can rebuild the rear CV joint while it is on the car. Review our tech article on driveshaft removal.

In this tech article, I will show you how to rebuild the driveshaft on BMW Z4M models, other Z4 models are similar.

Keep in mind that when your car was serviced before, parts may have been replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have, so be prepared with different size sockets and wrenches.

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Do not work on your vehicle if you feel the task is beyond your ability.

Vehicle models change and evolve as they grow older, so the vehicle shown in our illustrations may vary slightly from yours. If something seems different, let us know and share your info to help other users. Questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.

Raise and support the rear of the vehicle on jack stands. See our tech article on jacking up your vehicle.

Remove the underbody splash shields. See our tech article on engine splash shield removing.

Remove the driveshaft. See our tech article on driveshaft removing.

On both the front a rear driveshaft halves make a paint mark (inset) to align both halves for reassembly.
Figure 1

On both the front a rear driveshaft halves make a paint mark (inset) to align both halves for reassembly. BMW uses a two piece driveshaft with a center bearing (purple arrow) supporting the middle of the shaft. This center bearing can wear out over time and you will feel a vibration and noise under severe acceleration and deceleration. Also the driveshaft uses a CV joint (yellow arrow) at the mounting point for the differential. CV joints can wear over time particularly with hard driving. You can extend the life of your driveshaft by repacking this CV joint with new special grease. A universal joint (red arrow) is also used in the driveshaft to allow the angle change at the rear differential. The U-joint bearings can dry out and cause a vibration when worn. If this is your issue, replace the rear section of the driveshaft.

With a wrench loosen the 18mm bolt (red arrow) that holds the driveshaft halves together.
Figure 2

With a wrench loosen the 18mm bolt (red arrow) that holds the driveshaft halves together. Use a flathead screwdriver (purple arrow) to hold the driveshaft still while loosening.

As you loosen the bolt gradually pull apart the driveshaft otherwise you will not be able to back the bolt out all the way.
Figure 3

As you loosen the bolt gradually pull apart the driveshaft otherwise you will not be able to back the bolt out all the way. There is a thin metal shield (inset) between the halves. Remember the location for reassembly.

Use a bearing puller and puller to pull the center support bearing off of the front half of the driveshaft.
Figure 4

Use a bearing puller and puller to pull the center support bearing off of the front half of the driveshaft. If just replacing the support bearing, reverse steps to install the new one. I find it will slide on almost all the way by hand, then lightly tap using a soft-faced hammer or use a shop press to install.

With pliers or diagonal cutters remove the band clamp (red arrow) that secures the CV joint boot to the shaft.
Figure 5

With pliers or diagonal cutters remove the band clamp (red arrow) that secures the CV joint boot to the shaft.

Using a soft-faced hammer, tap out all of the mounting fasteners with a mallet in the direction of the blue arrow.
Figure 6

Using a soft-faced hammer, tap out all of the mounting fasteners with a mallet in the direction of the blue arrow.

With a flat edge chisel tap the CV joint boot cover off of the CV joint.
Figure 7

With a flat edge chisel tap the CV joint boot cover off of the CV joint.

Use a puller to pull the CV joint off of the shaft.
Figure 8

Use a puller to pull the CV joint off of the shaft. This three jaw puller pulls evenly on the CV joint to pull it straight out. If you only have a two joint puller you will need an adapter bracket on the driveshaft side of the CV joint and use your puller to pull on the bracket and slide off the CV joint shaft with it.

If you do not have the special tools to remove the CV joint from the shaft you can still replace driveshaft CV joint.
Figure 9

If you do not have the special tools to remove the CV joint from the shaft you can still replace driveshaft CV joint. Rotate the outer CV joint race (green arrow) until you expose the ball bearings and remove them. Be sure to replace the gasket (yellow arrow) when reassembling.

If you are replacing the driveshaft CV joint you can now use a two arm puller to remove the inner CV joint race.
Figure 10

If you are replacing the driveshaft CV joint you can now use a two arm puller to remove the inner CV joint race. You will not be able to remove the cage around the inner joint race until the inner race is pulled off the driveshaft.

If you do not a have puller you can still disassemble the CV joint and repack it while it is on the driveshaft.
Figure 11

If you do not a have puller you can still disassemble the CV joint and repack it while it is on the driveshaft. Pull back on the CV joint boot to expose the joint. We have cleaned the joint for photographic purposes. Before you disassemble the CV joint note the position of the notch (green arrow) in the joint so you know how to reassembly it.

Rotate the CV joint outer race to expose the first few ball bearings.
Figure 12

Rotate the CV joint outer race to expose the first few ball bearings.

Pull out the ball bearings and rotate the joint to expose and remove each ball bearing.
Figure 13

Pull out the ball bearings and rotate the joint to expose and remove each ball bearing.

After you pulled the joint off you will notice two gaskets on the outer CV joint race.
Figure 14

After you pulled the joint off you will notice two gaskets on the outer CV joint race. The larger gasket (green arrow) fits between the joint and the boot as is available commercially. The smaller gasket (yellow arrow) is mounted on the differential side of the CV joint and is not available commercially so be careful not to break it.

With the joint disassembled clean the bearing surfaces of the outer race (green arrow), inner race (yellow arrow) and the bearing cage (red arrow).
Figure 15

With the joint disassembled clean the bearing surfaces of the outer race (green arrow), inner race (yellow arrow) and the bearing cage (red arrow). Avoid using solvents because they can leave a residue that will break down the new CV joint grease you pack the joint with.

Make sure the gaskets are firmly attached to the CV joint.
Figure 16

Make sure the gaskets are firmly attached to the CV joint. You can use silicone or glue to hold them in place. Start the assembly by placing the outer race over the cage and installing the ball bearings.

Rotate the outer race over the ball bearings you have installed.
Figure 17

Rotate the outer race over the ball bearings you have installed. Here we have installed three but you can start off by installing one or two at a time.

Rotate the drive shaft and rotate the CV joint to expose the empty slots.
Figure 18

Rotate the drive shaft and rotate the CV joint to expose the empty slots. Continue to install all of the ball bearings.

Install the snap ring over the end of the shaft to hold the CV joint on.
Figure 19

Install the snap ring over the end of the shaft to hold the CV joint on. Installation is the reverse of the removal steps. Pack the CV joint with special CV joint grease. If you have removed the entire CV joint press it back on the shaft. Install the snap ring. Tap in the driveshaft mounting fasteners with their brackets. Install the thin spacer and join the two halves. Fit the mounting bolt and tighten. Install the drive shaft according to our tech article on driveshaft removal.

If you are able to remove the joint from the shaft, you can clean and rebuild it on the bench.
Figure 20

If you are able to remove the joint from the shaft, you can clean and rebuild it on the bench. Rotate the outer race over the ball bearings (green arrows) you have installed. Here we have installed three but you can start off by installing one or two at a time.

Note the position of the large gap in the joint (yellow arrow) and the small gap (red arrow).
Figure 21

Note the position of the large gap in the joint (yellow arrow) and the small gap (red arrow). Install the fourth ball near the small gap, then the two final balls (green arrow).Rotate the joint until it is flush with the cage.

Install the joint on toward the driveshaft in direction of the green arrow.
Figure 22

Install the joint on toward the driveshaft in direction of the green arrow. Install the snap ring over the end of the shaft to hold the CV joint on. Installation is the reverse of the removal steps. Pack the CV joint with special CV joint grease. If you have removed the entire CV joint press it back on the shaft. Install the snap ring. Tap in the driveshaft mounting fasteners with their brackets. Install the thin spacer and join the two halves Fit the mounting bolt and tighten. Install the drive shaft according to our tech article on driveshaft removal.

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Comments and Suggestions:
Patricia Anderson Comments: Thank you for sharing your information. I have been trying to repair my BMW and these steps might help me. Thank you!

September 7, 2016
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 

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Page last updated: Wed 12/7/2016 03:03:46 AM