Onebad99TA

iTrader: (1)

I have a 99 Trans Am and recently did some suspension work. Installed Eibach Pro-Kit, BMR bolt-on relocation brackets, BMR boxed LCA's, Energy Suspension tranny mount (broken stocker) and torque arm mount (figured I might as well since I was under there anyway) and replaced the front two struts after I broke one of the damper shafts.

Since the install, I've noticed a LOT more vibrations. It's pretty mild idling in gear (A4) at a stop, and disappears when I pedal out gently. If I hit WOT in first gear, I'm greeted by a rather catastrophic vibration that gets worse as the revs increase. Settling back down in second gear, the vibration settles down a ton, but third gear is absolutely HORRIBLE, no matter the engine speed or load. Once the tranny gets into OD the problem disappears a great deal (this may be because I haven't gotten it over 65 since the install). I still have the stock T/A installed, and since it's not adjustable, I'm not sure how I could've screwed up the pinion angle. When I put it on, I did torque down the front 3 bolts (at the tailshaft mount) before putting in the back two bolts at the rearend. I just raised the rear with a jack until I could get the bolts in. Was this bad? Think I could fix this by just loosening all the T/A and LCA bolts and re-tightening them? Any other ideas? I realize that with urethane bushings, the mount won't absorb as much vibration, but this is kinda ridiculous! Any info would be greatly appreciated.



Thanks in advance guys,
Jason

DARK AGE 53

If it's doing it at idle I would take a close look tranny mount and T/A mount, I can only suggest you check to make sure everything is installed correctly and retorque all the bolts/nuts.

Al

trackbird

iTrader: (4)

Make sure the tranny mount didn't raise the transmission up until it is hitting the floor pan. I've not tried it, but I didn't think those fit the LS1 cars without using spacers (washers) to lower the transmission cross member to get the trans down away from the tunnel. Anybody know for sure?

DARK AGE 53

Haven't installed one on a A4 but we've done two M6's with no problems ( no washers used to lower the crossmember ).

Al

2002BlueWS6

Hey man my old Z28 did the same thing after I installed the Energy Suspension Tranny mount. Do yourself a favor and return it and buy a stock one from autozone. that's what I did and it totally eliminated all my vibration. Get that thing outta there and put the stock one back!

jimmyblue

iTrader: (11)

The mount, the drop, the T/A all have the
possible effect of really whacking out your
pinion angle (which is the likely source of
the vibration) and the new tail mount is a
much harder piece, coupling it nicely to the
body. Even if you replace it w/ stock you really
ought to get pinion angle checked / adjusted
properly, with all the stuff you've done.

Onebad99TA

iTrader: (1)

Thanks for all the info guys, I think I'm going to try just retorquing the bolts first, hopefully that will work, but I doubt it...If not, I'll take it somewhere and have the pinion angle checked/adjusted, and if that doesn't work I'll get a stock trans mount...Thanks a bunch.

-Jason

DARK AGE 53

You can have it check but it's a fixed T/A so there's no adjusting it, like I said if you have vibration while it's just idling take a look at the tranny mount or just replace with a stock unit.

Tom L. Busby

The poly trans mount is allegedly designed for the LT1, and it is a couple of mm's too tall. The top of the trans rubs against the tunnel and transmits a huge amount of noise at 2200 rpm and up.

A fix is to put one fender washer, with a 3/8ths inch hole I think, between the floor and the crossmember, at each of the 4 bolts that hold the trans brace to the floor. This will lower the trans back to stock height and the noise is basically gone.

A slight vibration is normal, but noise like a helicopter going by is not. The poly mount makes a little vibration you can feel through your feet rather than noise, to me, the way mine is set up, and the "rest of the story" is that I used 4 delrin fender washers.
Delrin is brand name for a harder and more durable type of nylon. It compresses very little and is a little harder than most polyurathanes.