View Full Version : Signs of Broken Motor Mounts?

12-31-2007, 05:50 AM
What are the signs of a broken motor mount?

I ask because I know something may be a bit wrong. **FYI I have installed a poly tranny mount last month - which is the only drivetrain/mount mod done to the car**

I have always had some movement in the stick shifter on my car, leading me to think the stock tranny mount was worn. I replaced it and it looked perfect (I dont beat on the car.) The poly unit was nice though, stiffened the movement a tad and it does its job.

However the shifter still moves to the right about an inch or so under hard acceleration... is this normal or is it supposed to be stiff as a hard-on with the poly tranny mount? lol.

I also have some bad wheelhop, and when this occurs the shifter pretty much gets thrown out of my hands (Im surprised the poly mount can warp like this).

MY MAIN CONCERN: Is that usually when shifting into 1st or sometimes 2nd and the shift isnt smooth (I'll purposely do it to test it out) the car will jerk forward (of course) but it seems like the engine/tranny/drivetrain rocks forward and back a few more times after the car jerks. Aka it "FEELS" like the engine and tranny are all loose, so when the car jerks to the right or left I can see the stick shift rock back and forth right and left 3-4 times a titch, and vise versa if its a bad shift forward and back.

This sure does sound like an engine mount issue, but when the hood is open and I tell my friend to give it some gas, the engine barely rocks. I dont have any banging with my long tubes either.

Enough with the info... what gives? What else you guys want me to answer to narrow this down? It's kind of annoying. I hope all that info helped.

I plan on driving my friends LS1 (have yet to drive another f body) to compare and see if its a normal-ish characteristic of the car.

12-31-2007, 07:53 AM
shocks, adj. LCA, relo brackets should stop wheel hop. your mounts are probably ok.

12-31-2007, 10:45 AM
it sounds like factory mounts, all my cars did that from the factory prolly not a problem

12-31-2007, 01:09 PM
IMO, if they are factory engine mounts, then they are probably broken or at least so stretched out that they aren't doing there job properly.

I have 125,000 miles on my 1999 Z-28 and I live in a moderate climate. I just replaced the mounts and was appalled at what the stockers looked like. My drivers side y-pipe was hitting the floorboard, which prompted me for the change.

12-31-2007, 06:10 PM
Thanks for the responses.

12-31-2007, 06:41 PM
I ripped apart two 1LE trans mounts before I figured out the left motor mount was gone.
It was so bad when we pulled the clamshells apart the rubber fell out on the floor.
I now have prothane motor mounts and an ES trans mount with no problems except the normal added vibration.