PewterScreaminMach

iTrader: (7)

I've had my car in the air since July when I decided to rebuild the transmission. Before putting the car up, there was no vibration. Yesterday I put it all back together (yeah, I was lazy on the rebuild hahaha) and there is now a vibration, especially noticeable at highway speeds. You can hear it, as well, almost like you can hear the whine from the 12-bolt, only it vibrates (if that makes sense...).

The only thing I can think of that MIGHT have changed between when I put it in the air and now is that I can't remember if I installed the torque arm bolted to the 4th hole from the bottom of the crossmember (BMR adjustable torque arm and BMR relocation crossmember) or the 3rd hole because they both looked drilled out a bit. I installed it this time in the 4th hole from the bottom. Could this instant center adjustment, if it actually is different, cause this vibration?

Obviously I'm gonna go back and recheck to make sure nothing is obvious with the driveshaft, but that's a pretty straight forward install with no room for adjustment. Any thoughts would be appreciated.

mook99ta

iTrader: (3)

Check your torque arm and your pinion angle too, and make sure you check to see if you threw a weight from your DS. That happend to mine and I had alot of vibration at highway speeds. Got it rebalanced and was good to go after that.

UMI Sales

iTrader: (1)

Hello
Just a few suggestions for you! Just make sure all of the hardware is tight. And check the pinion angle as well. And also if you are using a poly trans mount you will get a little vibration and road noise due to the firmer material. If you have any other questions feel free to ask and I will be more than glad to help.
Thanks
Brad

PewterScreaminMach

iTrader: (7)

Thanks for the advice, guys! I got under there yesterday but only had time to bleed the clutch and adjust the driveshaft safety loop (I had what sounded like a slight metal to metal rubbing sound, especially on the gas, and I think that might have been it). If I have tonight off, the car is still in the air so I'll get under there and double check all of the hardware, then hopefully have time to check the pinion angle. I do have a poly trans mount I installed in the Spring and I did notice more road noise with it, but I don't recall having this vibration when I pulled the transmission back in July, so I'll keep looking for possible culprits. If none of the above works, I'll try adjusting the instant center down one notch with the torque arm on the crossmember. If that doesn't work, I'll probably pull the driveshaft and maybe take it somewhere to check the balance.

Like I said, the vibration isn't bad enough to make the car undriveable, just annoying at certain speeds.

BMR Tech2

iTrader: (5)

Your pinion angle is off. Once you get the front of the torque arm where you want it then you have to set your pinion angle. I will post you a link to a video on our sight that explains the proper way to set your pinion angle. If you have any questions or still have the issues please give me a call and i can help you get it corrected.

http://www.bmrtvonline.com/video_detail.php?mId=3788

UMI Sales

iTrader: (1)

Hello
No Problem! Glad that I could Help. If you have any other questions or problems feel free to ask and I will be more than glad to help.
Thanks
Brad

PewterScreaminMach

iTrader: (7)

I'll definitely be checking the pinion angle, but I do have a question. You said, "Once you get the front of the torque arm where you want it..." How do I know where I want the front of the torque arm? I'm still not exactly sure how to check where I want the instant center and what the symptoms would be if I didn't have it set correctly. Once I can do that, I'll check the pinion angle.

By the way, could hard shifting have something to do with the pinion angle/instant center not being set properly? If drivetrain parts are off center while spinning at those speeds, couldn't this put pressure on internal transmission parts causing harder than normal shifting? Just curious as I've had issues with shifting before even though all hydraulics and clutch-related parts were setup properly on a freshly rebuilt trans. Talking about this made me realize the possible drivetrain angle connection.

PewterScreaminMach

iTrader: (7)

Update: I adjusted the pinion angle last night. Turns out it was about positive 1, so I changed it to negative 2.5 or so (BMR directions recommend between negative 2 and negative 3 for a manual car). I also kept the front of the torque arm mounted on the fourth hole from the bottom. It was raining so I couldn't test out any launches, but I did get it up to about 70mph just cruising and the ride seems pretty smooth. I've got a ridiculous amount of whine from the rear and transmission, as I always have, but at least the vibration appears to be gone. Hopefully tomorrow night the weather will be nicer and I can test it out thoroughly.

UMI Sales

iTrader: (1)

Sounds Good Man! I am sure you should not have any other problems. Keep us updated.
Thanks
Brad