engine mounts

[jlgp2007nc]

how do i know if its my upper or lower engine mounts that are bad? i have a really bad vibration at highway speeds. i jacked up the front end and put it in drive, tapped the gas and the whole car shook. should i just replace both uppers the lower and trans mount?

Lol...don't ever do that again. With the front wheels jacked up grab them and gently "wiggle" the wheel side to side then up and down. It should feel pretty tight up front. If it feels loose you may need to replace tie rods. If it's all nice and tight you may just need to get your wheels balanced. I recommend you have it checked out at a shop. Shouldn't cost much just to check things out. If it ends up being tie rods I recommend a shop again because you will need a wheel alignment afterwards. As far as mounts...pop the Hood....engage the parking brake VERY TIGHT!! have a friend put the car in reverse and drive while holding the brake firmly as well and see how much the engine rocks. If it jerks hard sideways or seems to twist....lower mounts. If it jerks hard forward or back then upper mounts. Other guys will chime in with more info and correct me If I made any mistakes.

[hadzmat]

i also just rotated the tires 2 wks ago when i did the brakes

[hadzmat]

im not getting hard shifts just a minor vibration and 40mph and a bad vibration at 70mph, also its seems to increase when the suspension drops after hitting a bump