Ok the other day I let my buddy have it and when it shifted into 2nd it busted loose and "THUMP" right under the console. After inspection I saw I ripped my trans mount above the crossmember apart. I purchased a Energy suspension mount today and installed it and it seems to be of better quality. Now the car doesn't feel like it shifts as hard and kinda seems like there is a little vibration when driving. Is it possible the drive shaft is out of balance now? What do you guys think?....Thanks

 

If you have a stock drive shaft, i.e. not aluminum, try taking the drive shaft loose from the pinion, rotating it 180*, and re-installing it. This cured my vibration problems above 75mph after I had some rear-end work done. I am assuming you took out the drive shaft and didn't mark it for re-install.

 

Didn't take the driveshaft off. I just replaced the broken trans mount that attaches to the cross member. Does anyone think maybe I twisted the drive shaft (appears ok) or threw it out of balance somehow? I'm going to take it to the GM dealer to see what they think but I would like any opinions from you guys first. Thanks

 

It never hurts to get your driveshaft balanced. I used to do it every year in my GN. With a polyurethane trans mount you'll feel way more driveline vibration than with the stock rubber. Also there have been instances where the aftermarket mounts are a little taller than the stock, which moves the trans up a bit and may put the u-joints slightly out of phase....Just things to check, hope this helps...
--Alan

 

totally normal with a poly mount.

Quote:

Is it possible the drive shaft is out of balance now? What do you guys think?....Thanks

Is it worse at some speeds than others? if so, then yes it could be off balance. Some LT1 shafts had the yolk welded off-center causing an unfixable off-balance (the DS is actually skip-roping tight circles)... very common to see this around 75 to 100mph... then it smooths out to almost nothing around 120.

I've got a 3.5" Dynotech engineering shaft, newly rebulilt rearend, and I still find small vibes from the poly mount. And yes, now that the mount isn't squishing all over the place it WILL feel more stable/rigid and won't fell like it's shifting hard (less slack in the drivetrain to wiggle or "slam" between shifts). I noticed the same thing when installing my Prothane unit.

 

You guys are awsome .. I got to thinking about it and the design of this mount will not break away like stock and its alot stiffer so I was thinking it would transfer any vibration through the crossmember alot more than the stock one. I will have the shaft balanced just for precaution but I'm sure the mount is the cause of it. Thanks again

 

Did you use the spacer that comes with the ES mount? Mine vibrated substantially before I took it out.

Frank

 

Yes, It said you must use the spacer for preload... You took it off and had no probs?

 

I've been running without it for almost 3 years. Using the spacer throws your pinion angle off, which causes the vibration....

Frank

 

ok, i just bought a new es mount today and i am going to install it on wednesday. is there anything i need to know about installing it. it seems likes it is a no brainer but i don't want to do something now that could lead to damage down the road.

 

It's a no brainer . The only thing I have a problem with is the extra plate that comes with it (preload spacer). It says it must be used! And I have vibration now and as you can see in this thread some people had the same problem and removed it to resolve it. I will be taking mine out tomorrow and hopefully the vibration will be gone. Will let you know

 

When I broke the tranny mount last year, it bent my AL driveshaft on the driveshaft hoop. I have a very hard shifting AT with the Transgo kit. The driveshaft was only 3 months old After getting a ES poly mount and putting on DR's, I snapped 3 teeth off the ring gear on a 1-2 shift