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Installed SYE, now vibes (??)

Porch951

Porch951

NAXJA Forum User
Location
Albuquerque, NM
I installed a SYE hack-n-tap kit from Iron Rock Offroad (basically a yoke + "refurbished" front driveshaft). I didn't really have many vibes before, but i knew i'd need it down the line, so i figured what the heck...

Now, at speeds around 60 i start getting some pretty nasty vibrations.

I tried contacting IRO to see if they had any suggestions, but so far (2+ weeks) they haven't returned my email, so, here i am!

I currently have a 3" lift. The IRO kit tells you to remove your transfer case drop, but i'm running a manual crossmember with an auto trans (so i have about a 3/4" drop, and i can't remove it). I have a D44 rear. When i measured 33.xx inches from the diff yoke, i would have ended up with 1/4" of splines--so i added 3/4" which they say is okay to do in the instructions. Eventually i plan to go to 4.5" lift so it'll probably even out anyways.

The install went really smoothly, i ran the engine with the trans in reverse to cut and drill the output shaft--it was a perfect cut and the hole is perfectly centered.

Any ideas? Is it possible i got a driveshaft that's out of balance, or is there some kind of minimum angle needed for a double-cardan driveshaft, or something like that?



TL;DR: I did the install correctly, i have a 3/4" transfer case drop and 3" lift, and i'm getting awful vibes at 60.

Few pictures:
P7311205.jpg


P7311206.jpg
 
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any play in the driveshaft? theres a reason they say 'refurbished' and not 'rebuilt'... i have no idea how they sleep at night selling junkyard driveshafts.

i was under the impression that the differance between an automatic and manual crossmember was where it mounted, front to rear... i didnt know they droped it too... is that an oem crossmember?
 
whats wrong with a junkyard driveshaft? I am running a junkyard shaft in the rear of my XJ, just replaced u-joints and off to the races.

your driveshaft could be unbalanced... but that is unlikely.

looks like your pinion angle is a little bit to low. try a set of 3* shims and see where that gets you.
 
What are the drive line angles ? Did you shim the axle ? How much ?

It is possible that the drive shaft balance needs to be checked.
 
xcm said:
any play in the driveshaft? theres a reason they say 'refurbished' and not 'rebuilt'... i have no idea how they sleep at night selling junkyard driveshafts.

i was under the impression that the differance between an automatic and manual crossmember was where it mounted, front to rear... i didnt know they droped it too... is that an oem crossmember?
Click to expand...
No play that i could find. I greased everything too. The manual crossmember does drop the transfer case down about 3/4" but otherwise it bolts straight up.

rockclimber said:
whats wrong with a junkyard driveshaft? I am running a junkyard shaft in the rear of my XJ, just replaced u-joints and off to the races.

your driveshaft could be unbalanced... but that is unlikely.

looks like your pinion angle is a little bit to low. try a set of 3* shims and see where that gets you.
Click to expand...
Not a bad idea, thanks!

Tim_MN said:
What are the drive line angles ? Did you shim the axle ? How much ?

It is possible that the drive shaft balance needs to be checked.
Click to expand...
I don't have an angle checker, i suppose that's the next step. No shims on the axle currently.

Is there a way to calculate pinion angle without an angle checker? Or should i order one?
 
You can get an angle checker for about $6 @ home depot.
Set it on the yoke face and measure.
The measures angle is the same as the pinion angle.
Draw it out on paper, it'll make sense.
 
Since you have the late style t-case,it could just be be the H-n-T kit itself.I couldn't ever get mine to work so I ended up going with the HD kit,been perfect for 10yrs now!
 
Drive shaft could be unbalanced, double cardan joint worn, or the slip section worn. I fought vibrations after I did my SYE for a while. Turns out the 3 shafts they sent me were all unbalanced.
 
I had the same problems with the IRO Hack n' Tap Kit. The Yoke itself had just a little play on the output shaft. I nearly got crazy, finding the reason for my vibes, because the yoke doesn't move at all when you test for any play by pulling on it. After I set my pinion angle perfectly right, changed my driveshaft into a brand new one (400 $ :cry:) and got the rear axle checked by my garage, i realized it HAS to be the yoke itself. So i took the driveshaft off and loosened the bolt that fixates the yoke to the output shaft. Then i tried to pull the yoke up an down by hand again...and, not very surprising, it had a little play. Unfortunatly, that "little play" is more than enough to cause horrible vibes beggining at 90 km/h (is that about 60 miles? :)) and is just getting more terrifying, the faster you get. By the way, the driveshaft-guy, i asked about the problem, told me that if the driveshaft would be out of balance you would just have vibrations in certain speed ranges. I solved the problem by installing a "real" SYE. I think it was the Advanced Adapters HD SYE. Install was easy and everything runs perfectly smooth and silent now.

Maybe that helps with your problem. lol just recognized: first time i write something after just reading in the NAXJA-forum for over two years now

BTW: Sorry, if my english is not perfect...im from Germany, and the last time i could travel to the US is 9 years ago! :bawl::patriot:
 
KingIce said:
I had the same problems with the IRO Hack n' Tap Kit. The Yoke itself had just a little play on the output shaft. I nearly got crazy, finding the reason for my vibes, because the yoke doesn't move at all when you test for any play by pulling on it. After I set my pinion angle perfectly right, changed my driveshaft into a brand new one (400 $ :cry:) and got the rear axle checked by my garage, i realized it HAS to be the yoke itself. So i took the driveshaft off and loosened the bolt that fixates the yoke to the output shaft. Then i tried to pull the yoke up an down by hand again...and, not very surprising, it had a little play. Unfortunatly, that "little play" is more than enough to cause horrible vibes beggining at 90 km/h (is that about 60 miles? :)) and is just getting more terrifying, the faster you get. By the way, the driveshaft-guy, i asked about the problem, told me that if the driveshaft would be out of balance you would just have vibrations in certain speed ranges. I solved the problem by installing a "real" SYE. I think it was the Advanced Adapters HD SYE. Install was easy and everything runs perfectly smooth and silent now.

Maybe that helps with your problem. lol just recognized: first time i write something after just reading in the NAXJA-forum for over two years now

BTW: Sorry, if my english is not perfect...im from Germany, and the last time i could travel to the US is 9 years ago! :bawl::patriot:
Click to expand...

Your english is very good, and thank you for the response.

To be honest that's what i was afraid of. In looking at the system, i don't see how 1" of splines and that bolt can hold the yoke stable. It's also interesting because i noticed that the vibes are never quite the same. Sometimes there are none, sometimes they're terrible, and other times they are manageable. At any rate it is undriveable at speeds beyond 60mph like this. Something is going to break or wear out!

Has anyone run the IRO (or other) SYE kit with no vibrations??

I wonder if welding the adapter to the output shaft would help? However i think it would be difficult to weld it without the weld pulling the yoke off to one side as it cools.

I'm not giving up on the shims yet either, but it is bothersome to me that i didn't have anything this bad with the stock driveshaft.
 
Did you shim the rear axle ?

Did you put the T-case in 4hi and remove one drive shaft and drive on the other one ?

Did you swap the front and rear drive shaft ?

Did you have the "new" drive shaft balance checked?

Good troubleshooting involves inspecting, measuring, and testing to rule in, or rule out, potential causes. Anything is possible, but you have to eliminate something from your list of suspects.

Many people have H&T SYE's and have no issues.
 
Tim_MN said:
Did you shim the rear axle ?

Did you put the T-case in 4hi and remove one drive shaft and drive on the other one ?

Did you swap the front and rear drive shaft ?

Did you have the "new" drive shaft balance checked?

Good troubleshooting involves inspecting, measuring, and testing to rule in, or rule out, potential causes. Anything is possible, but you have to eliminate something from your list of suspects.

Many people have H&T SYE's and have no issues.
Click to expand...
could be the front shaft and I'm willing to bet you should shim the rear axle.
 
Tim_MN said:
Did you shim the rear axle ?

Did you put the T-case in 4hi and remove one drive shaft and drive on the other one ?

Did you swap the front and rear drive shaft ?

Did you have the "new" drive shaft balance checked?

Good troubleshooting involves inspecting, measuring, and testing to rule in, or rule out, potential causes. Anything is possible, but you have to eliminate something from your list of suspects.

Many people have H&T SYE's and have no issues.
Click to expand...
I called IRO this morning and he suggested shimming the axle too. You're right, i'll start with that and go from there.

Unfortunately i'm many miles away from any place that can check/balance a driveshaft. Swapping driveshafts may be another good place to start.
 
Porch951 said:
Your english is very good, and thank you for the response.

To be honest that's what i was afraid of. In looking at the system, i don't see how 1" of splines and that bolt can hold the yoke stable. It's also interesting because i noticed that the vibes are never quite the same. Sometimes there are none, sometimes they're terrible, and other times they are manageable. At any rate it is undriveable at speeds beyond 60mph like this. Something is going to break or wear out!

Has anyone run the IRO (or other) SYE kit with no vibrations??

I wonder if welding the adapter to the output shaft would help? However i think it would be difficult to weld it without the weld pulling the yoke off to one side as it cools.

I'm not giving up on the shims yet either, but it is bothersome to me that i didn't have anything this bad with the stock driveshaft.
Click to expand...

The problem is that kit uses "slip" yoke like your factory driveshaft,and it was built to have a loose fit vs a HD kit where the yoke is almost a press fit.
 
I've been running the dirtbound SYE with a junkyard front shaft for a few weeks. I have no vibes from it. My cut wasn't straight, and neither was the hole I drilled, didn't make a difference. There is a small amount of play in the yoke, but no more than what was there with the factory yoke.
 
XJLI said:
x2 on whoever said front shaft. pull that out completely and drive, i bet all the vibes go away.
Click to expand...

Why? It never vibrated before. I've been driving it for years with very minimal vibrations--then i swapped to a SYE and the vibrations got horrible.
 
Porch951 said:
Why? It never vibrated before. I've been driving it for years with very minimal vibrations--then i swapped to a SYE and the vibrations got horrible.
Click to expand...

Dude. Shim your rear axle and get your pinion angle correct. Double cardan systems work than the stock single u-joint system. you need to line up the pinion angle or you ate gonna have vibes. Stop arguing with people online and get to wrenching.
 
rockclimber said:
Dude. Shim your rear axle and get your pinion angle correct. Double cardan systems work than the stock single u-joint system. you need to line up the pinion angle or you ate gonna have vibes. Stop arguing with people online and get to wrenching.
Click to expand...

I can't work on my Jeep while i'm at my day job. :moon: I was wondering why i got two votes for the front drive shaft when nothing changed but the back one?

I checked the angles. The driveshaft shows 14* while the pinion (or at least the flat part below the pinion) measures 13*. The guy at IRO said 3* but i guess i wasn't clear whether that was to raise or lower the pinion angle. Do i need 2* or 4* of shims?
 
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