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Satin Pearl White '04 Lexus IS300
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Discussion Starter · #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.
 

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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.
 

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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.
 

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2005 Lexus IS300
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switch to a 2 piece driveshaft. the ar5 has vibrations with single piece drive shafts,
[/QUOT
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)
 

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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.
 

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2001 AR5 Swap, Built NA-T, Standalone
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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.
 

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Satin Pearl White '04 Lexus IS300
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Discussion Starter · #11 ·
I’ve had my AR5 for 5 years and am using it with a one piece slip splined driveshaft. I also have the DM cv to u joint billet adapter. I’ve never had any kind of vibration with my set up.

What transmission cross member are you using? I’m inclined that it’s more of a driveline angle problem like @Hodgdon Extreme.
I am running a Curran Billet Aluminum trans mount. Do you have a link for that DM CV to Ujoint billet adapter? If that is what will solve my issue then that is what I'm gonna go for. Would much perfer keeping a 1 piece instead of swapping to a 2-piece.
 

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I am running a Curran Billet Aluminum trans mount
Good, that’s the best x-member you can get for our cars. Still on the stock rearend and bushings? Can’t figure how it could be an angle problem using the Curran x-member, but let’s cover the bases.

Do you have a link for that DM CV to Ujoint billet adapter?
Right here. Mine is a DriveShaftShop R154 shaft. I had it modded locally to fit the GM 1350 u joint ends. I’ve never had vibration issues in the 5 years I’ve had the car AR5 swapped.
 

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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.
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.
 

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2001 AR5 Swap, Built NA-T, Standalone
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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.
Amazing answer, thank you so much. The telescoping action is to account for the off measurements, but you'd think since they offer all OEM parts, they'd know this measurement already? Also glad to hear you don't have any vibrations. Since my motor's away I can get the final pieces in my hands and start driving sooner than later.
 

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Amazing answer, thank you so much. The telescoping action is to account for the off measurements, but you'd think since they offer all OEM parts, they'd know this measurement already? Also glad to hear you don't have any vibrations. Since my motor's away I can get the final pieces in my hands and start driving sooner than later.
I will say I did have any issue some others have had where the DM adapter rubs on the jzx shifter housing. Had to grind some off of the shifter housing so that it would clear but it seems to still make contact sometimes. Hoping it'll just self clearance over time cause I don't wanna have to pull the trans again.
 

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Satin Pearl White '04 Lexus IS300
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Discussion Starter · #17 ·
Good, that’s the best x-member you can get for our cars. Still on the stock rearend and bushings? Can’t figure how it could be an angle problem using the Curran x-member, but let’s cover the bases.



Right here. Mine is a DriveShaftShop R154 shaft. I had it modded locally to fit the GM 1350 u joint ends. I’ve never had vibration issues in the 5 years I’ve had the car AR5 swapped.
No, it has a full supplemental bushing set from FIGS along with a Mega Rear Kit.
 

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No, it has a full supplemental bushing set from FIGS along with a Mega Rear Kit.
Hmm, those should be perfect aligned, then. It’s a head scratcher for sure.

I'm really not sure, like I said, I bought the car with the swap done.
The rubber isolator should look like this pic. I took the pic from Currans thread.

Automotive tire Automotive lighting Hood Tire Motor vehicle


If your isolator is incorrect, I could see it throwing off the driveline angle.
 
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