polyurethane engine mounts

[Jonny-K5]

i've had a weird vibration ever since i replaced my tranny. it comes on at about 2500rpm and slightly increases with rpm. ive been thinking that maybe something was unbalanced like the torque converter or maybe a cracked flywheel.but i got performance rebuilt parts from bowtie so i kinda doubt that's the culprit. i just remember that i switched to polyurethane engine and tranny mounts(energy suspension)when i installed the new tranny. are they stiff enough to produce these vibes? anyone else have poly mounts with similar problem? before the truck was glass smooth from idle to 5k.

 

[Jonny-K5]

ttt

 

[sled_dog]

Poly mounts transmit a lot of vibes from the engine and drivetrain, you don't notice with rubber mounts. I've never run them(yet, have some for the S10) but thats what everyone tells me. Someone who runs them should know, TTT.

 

[Jonny-K5]

thanks for the reply. i think i might swap to new rubber mounts. even if it doesnt get rid of the vibes at least i'll know thats not the problem.

 

[rcamacho]

I've run solid mounts on all of my street rods. Any imbalance or driveline issues are magnified through the chassis. Probably making something like a loose bearing or bad DS angle more apparant.

 

[R72K5]

interesting

never thought of this one that way

hum
interesting,

rubber flexes the most so it all makes sense

 

[JDNobodi]

When you replaced your tranny, did you take apart your drivelines apart? I had to replace the ujoints in my rear driveshaft and notice the previous owner didn't have the driveshaft paused (u-joints inline) I swear the guy didn't have clue what he was doing. He must have done this whenever he had to pick a wrench. Another problem could be that you knocked off a balancing weight off the driveshaft.