Transmission and Engine Mount Questions (DIY)

[RRocket]

I just picked up a new to me 1999 911. When I let off the throttle, there is excessive drive line slop. In addition, at idle there is more vibration than should be expected. Therefore, I'd like to replace the engine mounts and the transmission mount.

As far as the required parts, can anyone point me in the right direction? As far as the install, is there a DIY?

I'll have the car on a hoist this week putting my my Fister Ds, so I intend to do the mounts at the same time.

Thanks! !

[xmac]

The engine mounts are one of the easiest DIYs. The 996 DIY section will show you how to remove the air intake box (air filter replacement) and there is a section on proper/approved engine support locations or do a search. You will also need to unbolt and remove the cold start emissions air pump ("secondary air injection pump") mounted to the left of the engine bay close to the left side motor mount.

There are two smaller M8 bolts on the top side of each mount and there is a larger M12 that is accessed from underneath. Replace one mount at a time and tighten the M8's to 18 lbs-ft, the large nut to 60 lbs-ft. I would start there before the tranny mount.

Nothing to do with the problem you are seeing but if you are going this far and just bought the car, I would replace the air filter and serpentine belt and check all of the belt pulleys for excessive play. You can also clean the throttle body butterfly. In addition, the vents on the bottom side of the air pump can be cleaned with a rag (it picks up a lot of lint, hair, and junk)

[RRocket]

Any idea if the tranny mount is a possible DIY? I'll be on a hoist..

[dgjks6]

Manual or tip?

For the tip I don't know. For the manual you have to drop the transmission and take it to a shop to have them press out the old mount and press in a new one.

However, there are alternatives.

http://forums.rennlist.com/rennforums/996-forum/782771-increase-996-chassis-stability-and-enhance-shifter-feel-and-accuracy.html

http://forums.rennlist.com/rennforums/996-forum/811134-transmission-mount-urethane-fill-diy.html

[RRocket]

Manual or tip?

For the tip I don't know. For the manual you have to drop the transmission and take it to a shop to have them press out the old mount and press in a new one.

However, there are alternatives.

http://forums.rennlist.com/rennforums/996-forum/782771-increase-996-chassis-stability-and-enhance-shifter-feel-and-accuracy.html

http://forums.rennlist.com/rennforums/996-forum/811134-transmission-mount-urethane-fill-diy.html

Ugh...You have to drop the tranny? That's a bit beyond what I was hoping. That tranny insert might be the way to go....

[RRocket]

Here's a DIY for the Boxster. Am I assuming correctly that the process for the 996 is very similar? Part even looks quite similar.

http://www.pedrosgarage.com/Site_3/Install_Front_Engine_Mount.html

[xmac]

It would have been that easy if they had made it a bracket attached to the tranny:

[RRocket]

So you literally have to drop the tranny? Or is there enough room to press it out while still installed?

Man...that looks like a PITA!!

[xmac]

Yes, you have to remove it and no there is not enough room. That is why I recommended that you do the easy engine mounts first (20% effort fixes 80% or more of the problem).

If you really want to replace the one on the transaxle, then you are in for at least $1000 clutch job and possibly the IMS bearing since you have already the tranny out of the car. One recommended thread to look through:

http://www.renntech.org/forums/topic/28781-diy-for-transmission-mount-rr/?p=180226#entry180226

Edited April 30, 2014 by xmac