Car vibrates after new Tranny mount

**third_shift|studios** · 09-01-2005, 07:00 PM

ok, this is weird....

i installed a new Prothane, polyurethane tranny mount from LM Performance. Anyway, the shifting is a lot smoother but the super-dense mount now dissapates all the tranny movement throughout the WHOLE CAR!!! i'm talkin' seat, steering wheel, floor-feels like i have 500 horses but i know i don't....it sucks man??!?! will this shit go away??

**third_shift|studios** · 09-01-2005, 08:12 PM

So to answer my own quesion, i went to LS1Tech.com and found the following:

Originally Posted by ls1tech

Prothane (Poly)- hardest - more Noise and Vibration - alot of guys can't take it and swap it out, die hard guys LOVE IT. Best performing, but very harsh, remember it is a performance car, not a Cadillac. Maybe not for a daily driver.

Energy Suspension (Poly) - Middle of the road - not as harsh as Prothane, but not as soft as stock. Firm enough to get rid of the banging and clunking, but not hard enough to transfer ALL of the Vibrations and noises in to the car.
Good for a daily driver.

Stock (rubber) - soft and mushy, quiet ride and no vibrations, great for NORMAL driving, but....Lots of banging and clunking on hard shifts and hard acceleration in lower gears. Lots of shifter movement. The rubber often tears, plan on replacing often. Even then you will still get some banging and clunking.

oh well...i wish this info was here, but i guess i'm the guinepig for it. Hopefully this will help someone in the future.

i really am thinking about swapping out my Prothane transmission mount for an Energy Suspension transmission mount

**02z28ls1** · 09-19-2005, 05:40 PM

OK-Does the harder tranny mount help keep the tranny from moving around when shifting? When I go to shift from 2nd to 3rd the tranny moves and then the shiftgate isn't where it should be-it's a moving target!At least that's what I think is going on-any ideas.I think the tranny mount being stiffer would help but does anybody make stiffer motor mounts also.It's a daily driver but I can live with a little vibration.Who carries the Energy Suspension stuff?

**02z28ls1** · 09-27-2005, 04:40 PM

I wanted to move this back up front to see if maybe someone could respond to my last post

-yeah-that one!

**third_shift|studios** · 10-06-2005, 10:16 AM

ha! this thread is sooo old...sorry i've not looked here for quite sometime....

yeah, i had major shift-gate problems that seemed to go away a bit with the install of the new mount. The one i got is rediculous stiff though, i'd suggest the "Energy Suspension" one as i've read it's the "middle ground" compared to mine and GM's stock mount.

I still have a few shift gate problems, and you mentioned motor mount-it might be worth putting a new one of those in too and i bet the whole drive train would link up perfectly.

**Joe K. 99 Zeee!!** · 11-22-2005, 03:35 PM

I just ordered an Energy Suspension mount from lmperformance.com. They seem to have better prices. I'm going to shave off the two "bumps" on top of the mount before I install it. Also there's a seperate plate (can't remember the name) that's included with the kit. I won't be installing this since I figure the bushing will be hard enough as it is. There's a post over at camaroz28.com concerning this.

**Joe K. 99 Zeee!!** · 11-29-2005, 09:48 AM

Posted my experience with it at the Mod Review Forum. There's a link to a helpful thread at camaroz28.com. To sum it up, yes there is more noise. No louder than an average aftermarket catback though. If you're experiencing a ton of vibration like in the first post than you may have more problems and the old mount may have just been masking them.

**hammertime** · 12-01-2005, 09:04 PM

I broke my stock mount during a dreaded 3-2 shift at WOT. I never had any banging or slapping before that, but I certainly did after. I could push the clutch in and coast, then let the clutch out abruptly and get it to slap one direction, then accelerate hard to get it to go back in the other. I got under the car and could lift the tranny and move it around.

I ordered an Energy Suspension mount from summit and have been very happy with it for over three years. Never a peep from it since.

**third_shift|studios** · 12-02-2005, 04:05 PM

wow! i dont' think my tranny mount was that bad! I know for a fact that i'd been driving on a bad one for a while though...i jsut figured it was another of those "it's just how they are things" anyway...the vibes are basically gone now, i can't really feel them, pretty much got used to them

**Joe K. 99 Zeee!!** · 12-05-2005, 07:36 AM

That's good to hear! It's funny though...I tried to read every post I could find on poly trans mounts before I got mine. The one thing I noticed was the wide variety of experiences. Some say hardly any noise increase, while other say it's crazy loud.

I'm considering getting an older 1LE mount I found and trying that. That part is discontinued now, but I think my mount may be getting little quieter. Maybe it's just me and I'm getting used to it. Others report the same experience though.

I wonder if the temperature makes a difference as well....summer vs. winter driving.

**oneBADDz** · 12-05-2005, 08:13 AM

Ahhhhhh hammertime. . .i feel for you and the 3-2 at WOT, my best friend did that three times and i don't think he has learned his lesson yet. I'm not putting any more pushrods in for him though. He did it racing a mach one right after they came out and all those stang guys were so cocky about those things and the guy STILL never passed him. 3-2 at WTO back to 3 then to 4, I wanted to cry for his '99 Z, I've never seen a tach jump so high so fast

**x10-wakerider** · 01-03-2006, 11:40 AM

I have a polyurethane tranny mount and i hate it!

**BIG D's SS** · 01-03-2006, 11:41 AM

I had the same problem bought a new stock mount and now it is smooth as a Cadillac. Polyurethane mounts suck ass.

**98tadriver** · 01-10-2006, 01:07 AM

ive got the energy suspension mount. you can still hear engine vibration and stuff, but it doesnt bother me. it sounds cool actually. almost sounds like i got a different exhaust on it. i snapped my old stock one after i installed spec stage 3

**hammertime** · 01-10-2006, 02:13 PM

Originally Posted by z_driver1

Ahhhhhh hammertime. . .i feel for you and the 3-2 at WOT, my best friend did that three times and i don't think he has learned his lesson yet. I'm not putting any more pushrods in for him though. He did it racing a mach one right after they came out and all those stang guys were so cocky about those things and the guy STILL never passed him. 3-2 at WTO back to 3 then to 4, I wanted to cry for his '99 Z, I've never seen a tach jump so high so fast

I got very lucky. It has happened to me twice, and both times I was able to get the clutch back in before I did any damage. That happened right after I got my car and I was racing my friends 70 Chevelle with .030" over 454 and Edelbrock heads. I still managed to pull him though!

rgvouter · 01-13-2006, 06:26 PM

Originally Posted by BIG D's SS

I had the same problem bought a new stock mount and now it is smooth as a Cadillac. Polyurethane mounts suck ass.

where can you buy a stock mount? been looking all over and cant find the stock rubber one?

**oneBADDz** · 01-13-2006, 06:36 PM

any parts store

**MdFormula350** · 01-15-2006, 08:34 PM

the strength of a prothane poly mount is well worth any noise / vibration increase. i plan to get on for my 4th gen, have one of my 3rd gen for 2+ years. i couldnt stand my auto tranny flopping around and hitting my tranny tunnel and making my console move around everytime i got on it. for the 3rd gens at least maybe the 4th gens as well, the prothane goes right in and doesnt have any extra pieces, the plate on the es one i think had caused issues with noise and such; not sure if they got rid of the plate or not but u cant go wrong with the prothane one.