87caprice318

iTrader: (1)

Hey guys, I'm stumped and getting super frustrated. My car is having a very bad vibration once I get to 2nd gear and even worse going to 3rd. (Higher RPMS) ONLY while RACING (track or street). Regular driving it's not there or barely noticeable if any.

Can't even make a full pass because of the vibration. I've had the driveshaft checked for balance, removed rubber Trans mounts to a energy suspension mount and it's still there. New ptc converter which does it's job, new Trans also. 4.10 gears installed correctly. Removed the 3.42 as the car did the same thing.

WHAT AM I MISSING? PINION ANGLE, ETC???

LQ4BU

Thats weird...I'll ask some guys I know and see if anyone has any ideas.

Doug G

I had an issue like that... found that the driveshaft yoke didn't go far enough into the trans.

Should go in all the way and only pull out 3/4" to make rear u-joint fit.

drecpt83

Converter bolts in there good? I had a similar issue with my car and it turned out to be the front pump on my tranny. Definitely irritating trying to track vibrations down.

ZONES89RS

iTrader: (25)

What does the pinion angle look like? What rear suspension?

BANDIDO79

I had high speed vibrations but it was because one of my front wheels was off balance..

87caprice318

iTrader: (1)

@LQ4BU, very weird but I may have it narrowed down some everything under it is new from Trans on back.

@DougG, thanks and I'm using 1330 joints on a custom shaft. I'm having about 3/4" or smaller just to get it in the rear end. The yoke goes in pretty far, the long 4l60 yoke is what I use.

@drecpt83, I've checked all that. I've been fighting this for about 3 months now and I've finally noticed the problem as my other Trans cracked at the bellhousing on drivers side.

@Zone, what's up bro.....haven't checked pinion angle but rear suspension consists of UMI uppers and Metco Motor sports lowers...I just started back driving the car as it's been in storage most of the year.

@Bandido, I had that checked out also prior to going to the track before and after I just cracked my last trans. New trans and converter in and still vibration only in high rpms....

87caprice318

iTrader: (1)

Well since I've replied to you all, I just wanted you all to know that I think I've found the culprit after spending too much money elsewhere.

Those dang rubber clamshell motor mounts were trashed...when I put the car in gear and stall it up, around 3500 rpm the whole engine seems like it wants to jump out of the engine bay. Looked down at the mounts and Jesus, the bolt has ripped through the rubber on the driver side.

Think since I never ran the car that hard I didn't notice until my last couple street races and at the track. But I order some of the poly inserts that'll be here tomorrow and hopefully that resolve the issue I've been chasing because I've checked and changed everything else.

I will let you guys know this weekend or early next week if that helped as I removed my new Aeromotive fuel pump yesterday because it was leaking around where the chrome meets the red anodized base. Called up Aeromotive and they said send it in as a seal was bad there. So I overnight it yesterday, hope to have it back this weekend #shrugs

velox65

iTrader: (9)

Had a similar issue recently, I took my converter loose, and spun it one bolt hole around and retried it. Fixed my vibration, was a new fti converter.

curtisrp

iTrader: (3)

Try checking the driveshaft and the rear end pinion angle. They could have too much angle.

curtisrp

iTrader: (3)

Sorry for the post I see that you fixed it.