BMW 428i Gran Coupe Trans Mount Replacement Cost

Know what price you should pay to get your vehicle fixed.

The average cost for a BMW 428i Gran Coupe trans mount replacement is between $98 and $117. Labor costs are estimated between $70 and $89 while parts are priced at $28. Estimate does not include taxes and fees.
Note about price: The cost of this service or repair can vary by location, your vehicle's make and model, and even your engine type. Related repairs may also be needed. Talk with a RepairPal Certified shop to learn which repairs might be right for you.

How does a Trans Mount work?

The transmission mounts outer casing provides a strong mounting point to the vehicle. This is made of metal because it will support the entire weight of the transmission, allow bolts to be tightened into it, and must be machined perfectly flat to avoid vibrations. Inside this metal housing, the rubberized damper is tightly fit to the outer casing and molded around the other metal portion which will be described momentarily. This prevents metal contact from the transmission side of the mount to the chassis side of the mount. Sometimes, for additional vibration prevention, the rubberized portion is filled with liquid as well. The metallic piece in the center of the rubberized insert is rigid and strong, and provides a way for the transmission to attach to the rubberized portion, which, again, is locked into the outer housing. When the transmission side metal bracket is bolted to the transmission and the chassis side is bolted to the chassis, the transmission is actually supported by the rubberized insert, and linked to it by the metal bracket and housing discussed.

What are the symptoms of a bad Trans Mount?

Since vibration prevention is the reason for the design of the transmission mount, you can guess that excessive vibration from the drivetrain is likely due to engine or transmission mount failure. Also, when the transmission mount is completely worn out, meaning the rubber insert has worn and failed, the transmission may begin to make clunking noises against the chassis. This is the noise of the metal bracket and housing contacting very harshly with very little padding. This would be noticed the most when the vehicle is being shifted into reverse or drive, when braking quick and hard, or when accelerating rapidly. In some cases, the transmissions movement may even cause the check engine light to illuminate or the engine to stall. This is due to excessive movement of the engine and transmission, which allows components to be damaged or loosened. Lastly, front wheel drive vehicles may have clicking upon turns due to the sagging transmission mount causing the CV axle to bind while turning and accelerating.

Can I drive with a bad Trans Mount?

Leaving a transmission mount to further decay is a bad idea. The vehicle can be driven, but the transmission mount, as discussed earlier, can cause many issues if left uncorrected. The CV axles and wheel bearings for front wheel drive vehicles may fail repeatedly, and these will render the vehicle useless until repaired. For rear wheel drive and four wheel drive issues, the transmission output shaft seal and bearing or bushing is likely to suffer from sporadic lateral pressure from the driveshaft slip yoke. This will lead to leaks, driveline noise, and likely an extension housing replacement if the issue continues. The best recourse is swift action to correct the issue before the problem gets larger.

How often do Trans Mounts need replacement?

Transmission mounts, like engine mounts, are after specified for inspection on factory scheduled maintenance after 50,000 or 60,000 miles. The expectation is not failure at these points, but enough failures occur that most manufacturers decide to inspect this early. In general a set of motor and transmission mounts on a normally driven vehicle should be expected to last around 100,000 miles or more.

How are Trans Mounts replaced?

The engine and transmission must be supported, and this may be done with a transmission jack or engine brace, depending on the location of the mount and the orientation of the drivetrain. Once weight is removed from the transmission mount, the bracket will be disconnected from the transmission, then the housing will be removed from the chassis. Note that some subframe components or chassis crossmembers may need to be removed. The new mount is placed into the vehicle, attached first to the chassis, then the transmission is positioned in line with the new mount before bolting the transmission to the metal bracket extending from the rubberized insert. In some cases it may be necessary to adjust the other mounts for proper fitment, as the failing transmission mount can cause small movements to occur for the other mounts.

RepairPal Recommendations for Trans Mount issues

We recommend having the motor mounts inspected at major services. This should already be on the maintenance schedule, so follow the owner's manual guidance concerning the inspection and repair intervals. In general, transmissions require fluid and filter changes at the same interval they require transmission mount inspections.

What to look out for when dealing with Trans Mount issues

Keep in mind that motor mounts and transmission mounts fail gradually under normal circumstances. With every blow they absorb from the drivetrain they become unnoticably weaker. This will cause a long term owner of a vehicle to gradually adapt to the feel of the vehicle with bad mounts, and leads to increased repairs of the CV axle and wheel bearing assemblies. Also, some motor and transmission mounts are required to be adjusted for exact positioning. This will eliminate the possibility of excessive vibration from the new mounts.

Can I replace the Trans Mount myself?

For most transmission mounts, the experienced DIYer can take on replacement with no problems. However, when precision alignment of the mount is required, even experienced technicians may have issues eliminating vibrations after installation. In theory, there should be no trial and error to adjusting the mount, but since aftermarket parts are likely to be used, the mount may not align as the factory mounts once were. If supporting the engine and transmission is not possible for the exchange, or excessive vibration is noticed after the repair, consult a professional.

Trans Mount Replacement Cost Estimates

The average cost for a Trans Mount Replacement is between $98 and $117 but can vary from car to car.