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Aisin AR5 Swap Vibration

5K views 30 replies 10 participants last post by  _zaclemore 
#1 ·
Hello everyone, my car is running an AR5 right now. I am having a vibration issue over approx. 55mph, that gets progressively worse as the car speeds up. Definitely a drivetrain vibration. I'm being told that it could be my 1 piece u- joint driveshaft, and that many other AR5 cars suffer from the same problem. The solutions are a) Get a new driveshaft from Xcessive (they aren't making them and won't be for a few more months due to COVID) b) Take my driveshaft to a shop, and have them fit cv joints in place of the u-joints (I'm not very well versed in this swap, and am unaware of the details of this procedure) and c) Find a stock 2-piece driveshaft and fit the DM adapter to it. (I am assuming the adapter is what allows the driveshaft to fit to the back of the trans) I am just curious what my best bet, and fiscally viable option is. I know this is a lot, but you have all helped me in the past. Thank you guys!

Hayden.
 
#6 ·
switch to a 2 piece driveshaft. the ar5 has vibrations with single piece drive shafts,
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I had a one piece aluminum driftmotion driveshaft with my R154. It didn't vibrate.

Now I have a one piece aluminum Driveshaft shop unit with my T56 magnum. It doesn't vibrate.

I don't think it's fair to simply say it's a "one piece driveshaft" problem. Aluminum shafts definitely damp vibrations better than steel, but the most likely culprit is poor U-joint angles.

U joints do not have constant angular velocity (Constant Velocity joints do) - so a pair of U joints must work in tandem with equal/opposite angles to cancel out the vibrations created. Double Cardan U joint arrangements address this issue inherently.

If your forward U joint is pointed downwards at 3º but your rear joint is pointed upwards at 5º, you'll get vibrations.

First thing first - ensure the joints are in good shape with no play. Ensure the slipyoke of your shaft fits the bushing in the trans with minimal play. If that all looks good, investigate your U joint angles. Shim the trans mount and diff mount to achieve equal U joint angles.
glad someone with more knowledge chimed in. theoretically the two piece drive shaft will change the angle of the ujoint but I didn't even think of shimming the trans (theoretically does the same thing but 90 percent cheaper)
 
#4 ·
I had a one piece aluminum driftmotion driveshaft with my R154. It didn't vibrate.

Now I have a one piece aluminum Driveshaft shop unit with my T56 magnum. It doesn't vibrate.

I don't think it's fair to simply say it's a "one piece driveshaft" problem. Aluminum shafts definitely damp vibrations better than steel, but the most likely culprit is poor U-joint angles.

U joints do not have constant angular velocity (Constant Velocity joints do) - so a pair of U joints must work in tandem with equal/opposite angles to cancel out the vibrations created. Double Cardan U joint arrangements address this issue inherently.

If your forward U joint is pointed downwards at 3º but your rear joint is pointed upwards at 5º, you'll get vibrations.

First thing first - ensure the joints are in good shape with no play. Ensure the slipyoke of your shaft fits the bushing in the trans with minimal play. If that all looks good, investigate your U joint angles. Shim the trans mount and diff mount to achieve equal U joint angles.
 
#7 ·
Shim the trans mount and diff mount to achieve equal U joint angles.
This is what one of the Aussie Altezza boys ended up doing when he went to big boost and R154 (or maybe it was another trans? AR5 arent a common tranny down under), he was getting a lot of vibrations when drag racing his car after the swap, shimming the trans and diff seemed to eliminate most of it till he decided to get a better driveshaft made.
 
#5 ·
Another thought, from back in my Mustang days:

Ford installed a weight, mounted to the differential housing via rubber bushings, to help eliminate driveline vibrations because they couldn't achieve proper U joint angles. Here's a pic; it's the chunk of steel hanging below the housing, just rearward of the pinion flange:



We called them "moose balls". The common logic at the time was you could eliminate your mooseballs and save some weight if you upgraded to an aluminum driveshaft. I did this, and never noticed vibrations.
 
#10 ·
I also read up on the AR5 threads about this vibration, if it is a driveshaft angle problem, which it seems to be, a lot of stress has been relieved from me. Also, to keep on topic, how long is your guys' AR5 driveshafts? I read on the AR5 swap thread that it should be 51', but my engine's being build so I can't measure.
 
#13 ·
I just finished the swap. My measurement was 50.75 from the 6 bolt output flange with no adapter to the diff. The driveshaft DM sent has a telescoping front piece I'm not sure if they've always come that way but I'm sure the telescoping helps for variances in length and angle. So far I haven't noticed any vibrations but I haven't put that many miles on the car since the swap.
 
#22 ·
I'd tell you if I was able. I ordered a driveshaft from Xcessive and they sent me the wrong size. They're going to fix it, just annoying after confirming the length. One thing that did help me though, was tightening the bolt on the transmission in the middle of where the CV adapter goes. Big staked bolt, just put it in reverse and hit it with the impact for a sec. Mine was loose, as many are, and the car feels a lot smoother up to 65, but not perfect yet. I suppose the CV shaft will fix it fully. I also have poly diff bushings and subframe supplement bushings.
 
#23 ·
That's good to know, mine developed the vibration at certain speeds its the worst from 60-70 and 90-100. I was thinking about ordering one from xcessive. I'll have to have them triple check the length if I do. Were they pretty quick making it or did it take them a while?

Also when you say put it in reverse do you mean the bolt is a reverse thread? or to put the transmission in reverse before tightening the bolt?
 
#30 ·
Finally went to the only driveline shop in my area to see if they'd try to balance my DM shaft, didn't really get the vibe that they gave a shit so that's gonna be a no go. Decided to pull the trigger on the xcessive driveshaft, hoping for some good results. The vibration is getting pretty unbearable especially at higher speeds. I'm hoping the xcessive one holds up ok, the CV joint seems a little thin @_zaclemore how much power is your car making?
 
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