I have a 700r4 modded by monster transmissions in Florida in my 88 iroc, it's vibrating at higher speeds and sometimes even lower speeds higher rpms will do it, it usually comes in an almost wavelike pattern except at higher speeds where it steady. Also sometimes it does weird stuff while I'm driving, like make a random noise. A small clunk or a little grind sometimes. I'm definitely not a transmission person. Anyone know what the culprit might be? And what I'm looking to spend to fix it? Or if I could fix it (I wouldn't hold my breath on that haha)?

 

How are you sure its the trans?
There have been a lot of vibration threads that ended up being a drive shaft or wheel/tire issue.

 

Was about to say the same thing. Also could be a broken tranny mount causing rattles. Check out the u joints first

 

What kind of tranny mount are you using? I used to have a polyurethane one and I had those same issues. I put in a stock rubber one and it was all gone. Acted like a different car......

 

"it usually comes in an almost wavelike pattern except at higher speeds where it steady. Also sometimes it does weird stuff while I'm driving,"

I have seen this as a tire issue a few times over the years. This could be a possible cause.

 

Alright I'll comb through them, thanks