Poly Transmission Mount - Tips and Impressions
08-12-2005, 08:19 AM
#1
Poly Transmission Mount - Tips and Impressions I was looking all over the forums for some good info on the poly mounts but only found bits and pieces, so I decided to create this post in the hopes that it will help some people.
First of all, I have a 99TA M6 and recently needed to replace the tranny mount. I decided to get a poly one, but was worried of the noise problems I've heard other people post about. I still have the rubber TA (torque arm) and rubber engine mounts. I'm going to be changing those soon and will report back if I feel it necessary.
Our cars use a standard GM tranny mount, nothing fancy or exotic. Your local parts store will try and tell you they don't stock the ones for our cars, but just ignore them and get the standard GM universal mount. I picked up an Energy Suspension unit from my local speed shop, part number 3.1108R for red and 3.1108G for black.
The basic installation is described here at the Install University.
I will fill you in on the specifics concerning the poly mounts. I can't speak specifically to the Prothane mounts as I haven't seen those. The Energy Suspension mounts will come with a metal bar called the preload spacer, 2 bolts and various washers. After looking at everything under the car I decided that the preload spacer bar is not needed, I also removed the 2 bumps that the spacer would have compressed. I just used a bench grinder to remove the raised bumps. It was quick and easy to do. All that I can see the bumps and preload spacer doing is compressing the polyurethane making it firmer and hence, more likely to transfer NVH (noise vibration harshness). The rubber mount had no preload on it and worked fine and the poly is so much more firmer and stronger that I see no reason to make it even more firmer. If anyone knows of a reason to use the preload spacer as is, let me know.
The other down side to using the preload spacer is that it will add height to the tranny mount. This will move the tranny higher and it could possibly come into contact with the floor board which will definetely create NVH. Even if the tranny doesn't touch the floorboard it does change the drivashaft angle slightly. Some people have said that the angle change can produce noise. I don't know, but it doesn't sound worth taking a chance on.
Now I believe the modded (no preload spacer, removed bumps) tranny mount is just about the same overall height as the factory mount which is good. If you find that your tranny is a little too high you can lower it by installing washers in between the trans crossmember and the car body. It's best to use large diameter, flat washers to help spread the load.
You can reuse the bolts that hold the mount to the tranny. For the mount to crossmember you can use one of the supplied bolts that come with the mount. You will use the center hole of course. I tightened everything up with red locktite just to make sure they don't vibrate loose.
Here are some pics to help describe what to grind off:
Once done, it will look like this:
______________________________________
Impressions:
Sound:
IF, IF I roll up the windows, turn off the radio, put AC fan on low I can hear a little more gear whine from inside the tranny. Under heavy acceleration I think there is more overall noise than with the rubber mount. I'm just guessing as I can't be sure. So basically there was almost no noise increase. Now if I roll the windows down, or turn on the radio, or open my exhaust cutout (exhaust was going through Magnaflow muffler during listening tests), or just turn the AC fan speed up I can't hear any increase in noise at all. So basically no noise increase in my case. Hip, hip, hooray!
Vibration:
Just cruising down the road I think I can feel a little more of the car. I can't say for sure. It's really a good feeling, nothing harsh. The car feels a little more solid.
Under heavy acceleration I can definately feel a little more vibration than before. Again, no big deal, it just feels more solid. It's so faint that I think I'm getting used to it already. So the vibration thing is practically a moot point. Hip, hip, hooray again!
Shifter Feel:
This was the big surprise (I have a Hurst Billet Pro). Previously I have been having a hard time getting nice smooth shifts all the time. Sometimes I'm in the zone and can be smooth, but other times I feel like I can't synch the engine to tranny worth a damn. I know I'm a good shifter, but I tend to shift quickly all the time. If I let the clutch out real slow the shifts get smooth, but who does that, right?
After the poly mount, my shifts have been smooth as glass. Both upshifting and heel/toe down shifting under braking. I mean the shifts feel so much better without all that slack that was in the driveline. This reason alone makes the swap worth it.
I'm so pissed that I didn't do this earlier. It wasn't me this whole time, it was the damn spongy mounts that were screwing up my shift feel. Sorry about the rant, but I have to vent.
Anyway, the shifter handle handle feels so much more solid in my hand and when shifting, it will only torque over a little and that's it. No more moving around. It feels solid and I have more confidence in my shifts. So hell yea, hip, hip hooray!
I couldn't be more pleased with this tranny mount change. I'm looking into swapping both the torque arm bushing and the motor mounts with poly as well.
If you have any questions, let me know.
Jason
First of all, I have a 99TA M6 and recently needed to replace the tranny mount. I decided to get a poly one, but was worried of the noise problems I've heard other people post about. I still have the rubber TA (torque arm) and rubber engine mounts. I'm going to be changing those soon and will report back if I feel it necessary.
Our cars use a standard GM tranny mount, nothing fancy or exotic. Your local parts store will try and tell you they don't stock the ones for our cars, but just ignore them and get the standard GM universal mount. I picked up an Energy Suspension unit from my local speed shop, part number 3.1108R for red and 3.1108G for black.
The basic installation is described here at the Install University.
I will fill you in on the specifics concerning the poly mounts. I can't speak specifically to the Prothane mounts as I haven't seen those. The Energy Suspension mounts will come with a metal bar called the preload spacer, 2 bolts and various washers. After looking at everything under the car I decided that the preload spacer bar is not needed, I also removed the 2 bumps that the spacer would have compressed. I just used a bench grinder to remove the raised bumps. It was quick and easy to do. All that I can see the bumps and preload spacer doing is compressing the polyurethane making it firmer and hence, more likely to transfer NVH (noise vibration harshness). The rubber mount had no preload on it and worked fine and the poly is so much more firmer and stronger that I see no reason to make it even more firmer. If anyone knows of a reason to use the preload spacer as is, let me know.
The other down side to using the preload spacer is that it will add height to the tranny mount. This will move the tranny higher and it could possibly come into contact with the floor board which will definetely create NVH. Even if the tranny doesn't touch the floorboard it does change the drivashaft angle slightly. Some people have said that the angle change can produce noise. I don't know, but it doesn't sound worth taking a chance on.
Now I believe the modded (no preload spacer, removed bumps) tranny mount is just about the same overall height as the factory mount which is good. If you find that your tranny is a little too high you can lower it by installing washers in between the trans crossmember and the car body. It's best to use large diameter, flat washers to help spread the load.
You can reuse the bolts that hold the mount to the tranny. For the mount to crossmember you can use one of the supplied bolts that come with the mount. You will use the center hole of course. I tightened everything up with red locktite just to make sure they don't vibrate loose.
Here are some pics to help describe what to grind off:
Once done, it will look like this:
______________________________________
Impressions:
Sound:
IF, IF I roll up the windows, turn off the radio, put AC fan on low I can hear a little more gear whine from inside the tranny. Under heavy acceleration I think there is more overall noise than with the rubber mount. I'm just guessing as I can't be sure. So basically there was almost no noise increase. Now if I roll the windows down, or turn on the radio, or open my exhaust cutout (exhaust was going through Magnaflow muffler during listening tests), or just turn the AC fan speed up I can't hear any increase in noise at all. So basically no noise increase in my case. Hip, hip, hooray!
Vibration:
Just cruising down the road I think I can feel a little more of the car. I can't say for sure. It's really a good feeling, nothing harsh. The car feels a little more solid.
Under heavy acceleration I can definately feel a little more vibration than before. Again, no big deal, it just feels more solid. It's so faint that I think I'm getting used to it already. So the vibration thing is practically a moot point. Hip, hip, hooray again!
Shifter Feel:
This was the big surprise (I have a Hurst Billet Pro). Previously I have been having a hard time getting nice smooth shifts all the time. Sometimes I'm in the zone and can be smooth, but other times I feel like I can't synch the engine to tranny worth a damn. I know I'm a good shifter, but I tend to shift quickly all the time. If I let the clutch out real slow the shifts get smooth, but who does that, right?
After the poly mount, my shifts have been smooth as glass. Both upshifting and heel/toe down shifting under braking. I mean the shifts feel so much better without all that slack that was in the driveline. This reason alone makes the swap worth it.
I'm so pissed that I didn't do this earlier. It wasn't me this whole time, it was the damn spongy mounts that were screwing up my shift feel. Sorry about the rant, but I have to vent.
Anyway, the shifter handle handle feels so much more solid in my hand and when shifting, it will only torque over a little and that's it. No more moving around. It feels solid and I have more confidence in my shifts. So hell yea, hip, hip hooray!
I couldn't be more pleased with this tranny mount change. I'm looking into swapping both the torque arm bushing and the motor mounts with poly as well.
If you have any questions, let me know.
Jason
Last edited by JasonWW; 08-12-2005 at 08:27 AM.
08-12-2005, 10:44 AM
#2
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I'm going to be doing this soon. Nice writeup, I will definitely come back to this thread when its time. My rubber one is busted AGAIN. When you take off the shifter comes UP and when you let off, it goes down. The clunk noise is impossible to not notice 
I also believe the torque arm bushing is bad too.
I also believe the torque arm bushing is bad too.
08-12-2005, 10:49 AM
#3
My factory trans mount had an external safety interlock that prevented the tranny from touching the tunnel. I never got a thump. I did notice that the shifter started to rise higher and higher under acceleration as it started to break.
I guess my trans mount is rare as I've yet to see another like it.
I guess my trans mount is rare as I've yet to see another like it.
08-12-2005, 10:53 AM
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When I got this car about a month and a half ago, it appeared to have the stock mount in it (over 100k car btw) and it was pretty busted. Looked terrible. Im sure this one looks as bad or worse, so I try not to get on it a whole lot. I just hear BANG a lot instead of the tires chirping.
Also, how much did you pay for the new mounts?
Also, how much did you pay for the new mounts?
08-12-2005, 03:08 PM
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i to have the prothane mount. i think that the vibration has pretty much went away with use. either that or i have gotten use to the additional vibration. its nice to look down and not see my pro5.0 dancing around under hard accelleration anymore.
justin
justin
08-12-2005, 06:14 PM
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I have the Prothane tranny mount. I noticed more rumble in the seat from the true duals the moment I first started the car. It has alot more rumble in the seat and car in general on heavy acceleration. I like it.
I also agree about the more positive feel of the rearend & suspension. It is move positive and whole over bumps and bridge spanners. I have a little bit of vibration at 80 mph in 6th gear only. I think this is directly linked to my howling pinion bearing in the rearend. The 315 BFG DR's have been the death of the stock 10 bolt.
I also installed the torque arm bushing. It makes the car hook up so much better. You feel like you are faster but are really just getting more of your power to the ground. Definately a must do after the tranny mount.
I have Prothane motor mounts to be installed. Hope to be in this week end but may not be until next week end. Great write-up, by the way.
Dave
I also agree about the more positive feel of the rearend & suspension. It is move positive and whole over bumps and bridge spanners. I have a little bit of vibration at 80 mph in 6th gear only. I think this is directly linked to my howling pinion bearing in the rearend. The 315 BFG DR's have been the death of the stock 10 bolt.
I also installed the torque arm bushing. It makes the car hook up so much better. You feel like you are faster but are really just getting more of your power to the ground. Definately a must do after the tranny mount.
I have Prothane motor mounts to be installed. Hope to be in this week end but may not be until next week end. Great write-up, by the way.
Dave
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08-12-2005, 06:36 PM
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I have the poly trans, torque arm, and driver's side engine mount installed and my car feels pretty solid compared to the stock rubber ones. No more banging Y-pipe and like you guys also noticed, my shifter doesn't move all over the place when going WOT. Glad to hear the install went well for you.
08-12-2005, 09:23 PM
#10
Originally Posted by MattIROC
Also, how much did you pay for the new mounts?
the ES TA mount is about $11 and
the ES motor mounts run around $25ea.
The Prothane versions seem to run a few dollars more.
Judging from the responses from you Prothane trans mount guys, it appears it does transfer a little more noise than the ES one. Polyurethane can be mixed to a wide variety of durometers (hardnesses) from soft foam you can compress in your fingers to rock hard. I'm going to guess that Prothane makes their trans mount from a slightly harder mix and that is why you guys are getting a little more NVH than I got.
08-18-2005, 06:15 PM
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Do you guys have a part number on the torque arm bushing thats polyurethane? Auto Zone had none in stock, and would take a while to get. Advance and O Reillys didnt have it. I called a local shop that carries a lot of stuff, and they said you have to take the bushing out and see what size wrench fits on it so they can get the proper one? I thought that was BS. Thanks guys, I just picked up the Energy Suspension polyurethane tranny mount and hopefully putting it in today.
08-18-2005, 06:37 PM
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Yeah, that is odd about the bolt - but it is a 15mm as I recall. Anyway, just go to ES's website to get a part #.
We just put an SE TQ Arm bushing and Tranny bushing in my buddy's A4 '98 TA and he says the car feels much better - especially since the stock Tranny bushing was torn up pretty bad. I have all that in my M6 plus the driver's side motormount in poly by Prothane like Krab above. Really happy with it, but I did get some noise out of the Hurst shifter - just put some foam insulation in there around it and no more issues.
Wish mine was that PURDY BLUE one in the picture though!
We just put an SE TQ Arm bushing and Tranny bushing in my buddy's A4 '98 TA and he says the car feels much better - especially since the stock Tranny bushing was torn up pretty bad. I have all that in my M6 plus the driver's side motormount in poly by Prothane like Krab above. Really happy with it, but I did get some noise out of the Hurst shifter - just put some foam insulation in there around it and no more issues.
Wish mine was that PURDY BLUE one in the picture though!
Last edited by 1999Daytona500PaceCar; 08-18-2005 at 06:42 PM.
08-18-2005, 08:53 PM
#16
There are 2 main torque arm bushings, one has the lip of the arm facing away from the driveshaft and the other has the lips facing towards it.
Go here for the part numbers:
http://www.energysuspension.com/pages/cam2.html
Most of the LS1 cars have the lips facing away and use the 3.1111, but check yours to make sure. You will also need to remove the whole thing so you can grind out the rivets, take the old rubber out of the clamshell, put the new piece in, trim the width so that the clamshell closes without squeezing the bushing too tight that the arm can't slide in it, lube it up and then bolt it into place.
I haven't done mine yet, but if there are any tricks or tips I'll let you know.
AZ isn't likely to carry it, check your local speed shop or get it online. Jegs, Summit, forum sponsors, etc...
Go here for the part numbers:
http://www.energysuspension.com/pages/cam2.html
Most of the LS1 cars have the lips facing away and use the 3.1111, but check yours to make sure. You will also need to remove the whole thing so you can grind out the rivets, take the old rubber out of the clamshell, put the new piece in, trim the width so that the clamshell closes without squeezing the bushing too tight that the arm can't slide in it, lube it up and then bolt it into place.
I haven't done mine yet, but if there are any tricks or tips I'll let you know.
AZ isn't likely to carry it, check your local speed shop or get it online. Jegs, Summit, forum sponsors, etc...
11-28-2005, 06:52 PM
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I just installed an ES tranny mount, so I thought I'd push this back to the top and post my impressions.
I followed the instructions above and torqued everything down to factory specs. I didn't use any washers as spacers.
There is a definite increase in noise and vibration...more so while accelerating. It's nothing that's too bothersome though. It's comperable to the same noise level as an aftermarket performance catback system. If I was running a Borla, I probably wouldn't notice it much, but since I'm stock it comes out.
Some folks report that there's a break-in period and it'll quiet down evenutally. Hope so, but won't be too disappointed if it doesn't. Maybe I'll experiment with lowering the tranny a bit with the washers.
Thanks for a good write-up!!!
I followed the instructions above and torqued everything down to factory specs. I didn't use any washers as spacers.
There is a definite increase in noise and vibration...more so while accelerating. It's nothing that's too bothersome though. It's comperable to the same noise level as an aftermarket performance catback system. If I was running a Borla, I probably wouldn't notice it much, but since I'm stock it comes out.
Some folks report that there's a break-in period and it'll quiet down evenutally. Hope so, but won't be too disappointed if it doesn't. Maybe I'll experiment with lowering the tranny a bit with the washers.
Thanks for a good write-up!!!
Last edited by Joe K. 99 Zeee!!; 11-28-2005 at 06:59 PM.
11-28-2005, 09:02 PM
#20
I need to update my situation as well. About 3 weeks after the trans mount I added the poly torque arm mount. Even though the rubber pieces showed signs of tears starting, I really couldn't feel much difference. The noise level stayed the same as well.
After about a month I have noticed a very big increase in noise. It is a kind of resonance that is not noticabe with the windows down and the cutout open which I am most of the time. Now that we've had some pretty cold weather I've had the windows up more and it is very noticable. It's a resonance related to acelleration or decelleration. Speed doesn't matter. I can push the clutch in and coast at any speed and the noise goes away.
This is staring to bug me so I may replace the torque arm mount with a rubber piece.
The best way I've found to remove the rivets is to use a air powered cutoff wheel. Slice off the head and then use a punch and hammer to pop the rest of the rivet out. There are 2 bolts and a long stud holding it in place. Here are some pics of the old and new torque arm mount. If you need some more that show all the bolt holes for the mount, let me know.
After about a month I have noticed a very big increase in noise. It is a kind of resonance that is not noticabe with the windows down and the cutout open which I am most of the time. Now that we've had some pretty cold weather I've had the windows up more and it is very noticable. It's a resonance related to acelleration or decelleration. Speed doesn't matter. I can push the clutch in and coast at any speed and the noise goes away.
This is staring to bug me so I may replace the torque arm mount with a rubber piece.
The best way I've found to remove the rivets is to use a air powered cutoff wheel. Slice off the head and then use a punch and hammer to pop the rest of the rivet out. There are 2 bolts and a long stud holding it in place. Here are some pics of the old and new torque arm mount. If you need some more that show all the bolt holes for the mount, let me know.
