Driveshaft issues.

So I know there's many threads on vibration issues with stock and aftermarket driveshafts. I had an issue with a vibration around 50-55 and when I installed the BMR differential lockout kit, it's gone.

I think I had a faint vibration above 70mph with the stock driveshaft (hard to tell with slightly worn front tires) and now I'm back with my 1 piece and it's very evident. Rear view mirror is vibrating its ass off. I dropped the driveshaft off with a local drivetrain shop and they said it was definitely out of balance and they added a weight to it. I want to say it's slightly better, but I don't know. The shop came highly recommended by all the local racers. It was a lot cheaper than shipping it back to Shaftmasters (bought it from a forum member).

So in another thread, I read where one of our members lowered his transmission using shims and corrected the lower speed vibration. Would this be applicable to the higher speed vibration? Has anyone found a fix for it yet? I know there's a number of us with the high speed vibrations on a 1 piece from different brands. I've indexed the driveshaft and there's zero difference. Checked all the the surfaces and they're clean.

I posted when shimming the transmission cross-member down eliminated my vibration about 80-90% . I had NO vibration with stock DS and only started vibrating with 1pc aluminum. My vibration was at it's worst around 70MPH..

This may not work for others but it helped me.

SmokedSS said:

I posted when shimming the transmission cross-member down eliminated my vibration about 80-90% . I had NO vibration with stock DS and only started vibrating with 1pc aluminum. My vibration was at it's worst around 70MPH..

This may not work for others but it helped me.

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Thank you for your reply, I was looking for that other post to link it. I couldn't remember if you shimmed it down for the low speed vibrations or high. If can get relatively vibration free between 70-80, I'll be more than happy. I'm going to try this sometime this week.

I shimmed mine down 1/8", BMR said I could go 1/4" if needed.

SmokedSS said:

I shimmed mine down 1/8", BMR said I could go 1/4" if needed.

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I figured that's where I'll start too. Hopefully today is normal day and I can get home at a decent hour and try this out.

SmokedSS said:

I shimmed mine down 1/8", BMR said I could go 1/4" if needed.

Click to expand...

Do you have a pic of where/how you "shimmed" the crossmember?

Thanks

tevaburns said:

Do you have a pic of where/how you "shimmed" the crossmember?

Thanks

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yes, this x2!!

No. Its obvious when you look under the car there are 2 bolts on ea side. I had some special shims laying around. All you need are 4 washers same thicknesses with same support surface area as transmission pads to cross member. I would guess 3/4" or 7/8" flat washers would work fine. I will try and take pictures this weekend.

Finally tested this on my car today. Shimming down 1/4" helps, but not enough. Really disappointing. Now I gotta spend a ridiculous amount of money to ship this shit to shaftmasters...