Hey I'll take any help I can get. If that vibration is coming from the rearend, it's not one I'm willing to live with so I'll just have to take my tranny mount off if that's the case. My magnetic angle finder came in today so we will know once and for all if it's the pinion angle being thrown off. I didn't realize 3 degrees tolerance was so f'n small! I'll report back tonight or tomorrow on my findings.

 

OK, I removed the transmission crossmember and reinstalled my stock one. The vibration goes away. So, now the task is to figure out what the new mount is throwing off to cause this vibration....ugh!

 

What's your rear pinon angle?

 

Well, now it appears to be -2 degrees. But, I thought I had it set right before also. I've got me an angle finder now but can't get under the car without jacking up the rearend to measure the angle. I know the tranny and DS are at the same angle, best I can tell right now. Before, they were a couple degrees different. I'm thinking I'll either have to add something to shim the tranny up or down. Any thoughts on this? Surely I can't be the only person to ever have this problem by doing this one mod.

 

Well I am installing a 9", BMR Adj arm and the relocation bracket.
I measured some things before I took it appart. And also doing it on a lift so its easier to check things out.

When i initally installed the TA to the rearend mount I bolted it to the outside holes (puts arm closer to seat belt bolt). I didnt like that so I ground the mount to fit to the inside holes. Now i have the clearance I need, but now the TA is further away from the trans mount. Tonite Im going to cut the seat beltbolt and use the outside holes. I also noticed my header collector is closer to the floor. The new tranny mount moved the trans up almost 1/2 in. I have the prothane tranny mount and its got a shim between the mount and trans. Im going to remove the shim tonite to see if that helps. If that dont work im gonna modify the mount.

If the TA is teweeked to the side I think this will lead to harshness in ride quality and stress in the joints leading to fatigue. The tranny sitting higher will cause vibrations and make it dificult to adj. drive shaft and pinion angle.
I measured my stock TA height before I took it apart. If you hold a tape up to the side of the mount to the trans tunnel. I measured 6 1/2 in. to the bottom of the mount cup. Witch looks like the second row from top.

I just thought I'd pass this along.

These aftermarket parts just dont fit right and you gotta check everything twice.

 

Thanks for all the info. That does help my theory of the new mount moving the transmission up. I wish I would've measured the distance of both of them before reinstalling the stock one. I'm not real sure how to shim those outside bolts to fix the problem though. I guess I could have another layer of metal welded to the top of those two spots so it'd bring the mount down that much more, and go from there. I'm a little upset that I'd have to modify it any though... I guess that's part of it. I also tried using those 2 other holes on the tq arm but didn't want to grind the bracket. Once I took the car off the jackstands, when everything was settled it created more clearance, or what I felt was enough between the seatbelt and tq arm. Also, with it in the other 2 holes, it was way too close to hitting the tunnel.

 

I was checkin it out again and Im gonna remove the shim that the transmount came with. That seams to put closer to stock.
If you shim the mount down your gonna lose ground clearance.

 

Something to check... when I installed the Prothane mount in my car... it actually held the tranny solidly against the tunnel. I had to ride with it like that for a few days until I got an energy suspension mount for it. The Prothane mount was WAY too thick, and the energy suspension mount fit just right. Still a little more vibration than stock, but it mostly went away.

 

dont mean to Hijack but

#1 check your cross member

#2 I never set my pinion angle..

 

Maybe a little off topic but here's my setup with no vibrations at speed. Stock tranny crossmember, Energy Sus. Urethane Tranny mount, Stock driveshaft, UMI TA, and Motive gears.

Just got my UMI Chassis mount Adj. TA in yesterday. Adjusted the pinion angle to -2 and WHOA what a difference. It feels like a whole new car. A little vibration at idle and when taking off, and a little more rear end noise at some speeds. But damn, I don't care, it is well worth it. BUY THIS PRODUCT!!!!

 

What do you mean by it feels like a whole new car? Launchs better, drives better? Does it have a lot of noise created by that TA?

 

Definitely launches better... but it feels more powerful all the way through first gear. There is absolutely no slack in the rear end now, and as far as I know, it's had slack back there since day one. I dunno how to explain it... it just feels great. I'll admit, I was a little annoyed when I first started the car back up. A lot of vibration while I'm engaging the clutch in first or reverse. And it's noisy at about 50-60 mph going down the road, but not horribly so.

 

Any news on this? I had my driveshaft balanced and I put a stock rubber trans mount back in and I still have a horrible vibration over 60mph. Any help is appreciated, I'm getting discouraged at this point.

 

Do you have the stock tranny crossmember or an aftermarket one?

 

It's the UMI bracket

 

I have the yank crossmember and it added a lot of noise and vibration also. I put 1/4"
rubber belting between the chassis and the crossmember and it helped a little but did not completly solve the problem.I also rebalanced my new 31/2" pst aluminum driveshaft and set the pinion angle to -2 degrees. This is with a stock tranny mount.