Quick info. The car is a '95z A4. I replaced a transmission mount that was torn in half last night. It cured the sound I was having from the trans hitting the body under hard accelerattion, especcially downshifting under WOT. Well after ragging on her last night and some today just to make sure it solved it, the problem came back tonight. I'm 90% sure the new mount busted.

I'll get underneath her tomorrow, but what could cause this? The old one was pretty warm, should my trans and the mount itself be getting pretty hot? My speed sensor unit in the tail shaft right above it has a very small leak, could the ATF be eating the rubber? I'm kinda lost. Maybe my engine mounts are busted and all of it is being taken out on the trans mount under heavy load?

I'm kinda lost, I was just wondering if I could get any thoughts before I get underneath her tomorrow to just be dumbfounded.

 

Check all your motor mounts. If one is loose or broken it'll cause your transnmount to snap. Also check your rear suspension. Make sure everything is good aswell. I'd suspect a engine mount first tho. Especially since it's in such a short period of time.

 

Also buy the gm mounts. There better then the aftermarket ones or ones from the parts stores.

 

The trans mount takes alot of abuse in these cars. First off it holds the trans in the right spot, second it keeps the rear end in line. When you get on it hard the trans mount is twisted to the right from the engine torque and also lifted up from the torque arm from the diff. This is really hard on any mount, and more so if one of the other mounts are broken. Check the driver's side engine mount as well. Worn rear bushings can help tear a trans mount as well.

I have had good luck with Anchor engine mounts, but not matter what you use if you get on the throttle hard all the time, they will not last any longer than any other mount, and if you have another mount broken it will break even faster.

Massey

 

From your description of how you flogged the car, it sounds like you enjoy being ruff on the stuff. If you keep tearing through stock rubber style tranny mounts, you'll want to use a urethane mount instead. They are interlocked, and can't separate. Some guys may say you'll experience bad vibes if you use poly mounts, but I only noticed a slight increase on my 96 Z, which is to be expected. If you notice bad vibrations afterward, then that means you have other driveline wear issues. And I don't see a worn motor mount allowing the trans mount to tear. Your motor mounts are a clamshell style, so even a worn one will only let the engine rock a little bit, and certainly not lift the rear of the trans (that's what the torque arm is trying to do). Old style (non-clamshell) motor mounts could separate totally to where the drivers side of the engine would lift way up and bang the hood. I've had that happen, and even with that, didn't lose a trans mount.

 

I have the poly mount in my car and it has lasted so far. I used to rip rubber mounts to shreds in less than 2 days. I barely noticed the increase of vibrations in the car. One thing to remember though is to make sure you add some washers to make sure the mount sits the same height as the stock mount. If you don't, you'll have hell to pay. Believe me. I'm hunting for a new tranny now because if it. The poly mount will be lower profile than the original style mount. Add washers to the top and bottom of it to make sure it sits at the right height. Good luck.

 

Alright, time to compose a shopping list. I also have an edelbrock tubular torque arm, so I could imagine with less flex than stock it'd exert alot more force on the trans mount. I got the car in pretty rough condition, in most likely hood the rear bushings are toast also. I'll have to inspect the motor mounts. And can someone link me to exactly what rear bushings I need? That's be appreciated, I'm pretty ignorant when it comes parts like that.

Prothane Motion Control 7-1604 - Prothane Transmission Mounts - Overview - SummitRacing.com

 

Were you referring to the control arm when you said rear bushings?

Energy Suspension 3-3136R - Energy Suspension Control Arm Bushing Sets - Overview - SummitRacing.com

 

Yea, in some cases it may be cheaper to just get new arms when you factor in the cost of new bushings and machining (pressing the bushings into the arms)

Massey