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Rear Engine Transmission Mount Replacement
 
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Pelican Technical Article:

Rear Engine Transmission Mount Replacement

Tom Morr

Time:

1 hour1 hr

Tab:

$25 to $60

Talent:

*

Tools:

Floor jack, torque wrench, 13mm, 16mm ratchet and sockets, 17mm wrench

Applicable Models:

Mercedes-Benz SLK230 (1998-04)

Parts Required:

Transmission mount

Hot Tip:

Support the transmission with a floor jack.

Performance Gain:

Corrects annoying vibrations in the cockpit.

Complementary Modification:

Inspect driveshaft flex discs, replace if necessary.

Rubber isn't forever. Oil, ozone, heat and vibration degrade it. The R170 SLK's transmission mount is a prime example of an important part that eventually suffers from rubber failure.

A bad transmission mount (sometimes referred to as the "rear engine mount") not only transfers drive train vibration into the cabin. It also causes driveshaft misalignment, accelerating component wear.

To begin you must raise and support the car. Please see our article on jacking up and supporting your vehicle.

An automatic transmission is shown here but steps for a manual transmission are similar. The process is reversed to install the new mount.

Once the car is raised and secured with jackstands, the transmission's weight must be supported.
Figure 1

Once the car is raised and secured with jackstands, the transmission's weight must be supported. A floor jack can be used to support the transmission, either under the bellhousing or combined with a piece of wood to distribute the load across the transmission pan. The jack's pad will deform the pan if wood isn't used. On the R170, the transmission cross member is secured to the car with three 17mm-head bolts on each side (green arrows and socket; left side shown).

Two 13mm-head bolts secure the transmission mount to the cross member; loosen these.
Figure 2

Two 13mm-head bolts secure the transmission mount to the cross member; loosen these.

The cross member can theoretically be lowered on its bolts, but we took it out to facilitate photos.
Figure 3

The cross member can theoretically be lowered on its bolts, but we took it out to facilitate photos. Lowering it on its mounting bolts normally creates enough space to access the transmission mount. However, removing the cross member improves visibility for inspecting the driveshaft's front flex disc. On the right side, an exhaust bracket impedes socket access to the center cross member bolt. A 17mm combination wrench can be used, allowing the exhaust bracket to remain in place. The mount mates to the transmission with a 16mm-head bolt on either side. The mount's ears are angled with their tops facing the car's rear. If the mount is flipped, its base won't sit flush on the cross member.

The transmission mount has a steel structure that's isolated by vibration-absorbing rubber.
Figure 4

The transmission mount has a steel structure that's isolated by vibration-absorbing rubber.

The SLK's cross member aligns with the mount's center holes (green arrows).
Figure 5

The SLK's cross member aligns with the mount's center holes (green arrows). The process is revered to install the new mount.

This mount is fine.
Figure 6

This mount is fine. However, its rubber will eventually crack and decay. The ensuing metal-to-metal contact transmits vibration to the interior and accelerates driveline wear.

Transmission mount replacement is an easy DIY job.
Figure 7

Transmission mount replacement is an easy DIY job. These tools plus a floor jack and torque wrench are all that's required.

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Comments and Suggestions:
Gar Comments: What is the transmission code number for a 2002 Mercedes Benz SLK with a 6 speed manual transmission?
September 24, 2016
  Followup from the Pelican Staff: To be sure, Give our parts specialists a call at 1-310-626-8765

I don’t have that info. - Nick at Pelican Parts
 

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Page last updated: Sat 2/25/2017 02:27:41 AM