beerdriver1

I just got done installing a IRO H-N-t and hAve vibrations all over the place now?? I cut the output shaft and left 1 and 1/4" of spline and then had to cut the yoke another 3/4" off so it would not bottom out without touching the washer in the yoke. After I put everything back together I have about an inch of slip in the driveshaft. Took it out for a ride and from 30 mph on it has a pretty decent and constant vibe?? Has anyone had this issue before? I took out a inch transfer spacer with the original driveshaft and still have the rear pinion at a 3 degree angle. Before I did the H N T I had a small vibe around 30-40 but went away after 40. Now its worse and all over the place. Cant say I am too impressed at the moment!! ANy help or input would be great

93XJLI

Did you adjust your pinion angle? The yoke should point to the tcase..

dogger15

What are the conditions of the drive shaft

kidrock666

going to keep an eye on this as I have just ordered an IRO HnT for myself, hope you get it sorted!!

TheNerd

Compared to what? The pinion should really be 1-2 degrees below "optimal", as defined by this link.
http://www.4xshaft.com/driveline101.html
My guess is you need to properly shim your rear end....

BotakBeng

Where did you get the driveshaft from?

If i have to guess (assuming you have no issue before that), it would be
1)DS not balance
2)Worn out u joints

Try replacing the driveshaft with YOUR front driveshaft, that way you can narrow down the cause.

beerdriver1

OK, First I did the IRO H N T kit with a refurb shaft. 2nd I have the pinion angle real nice in my opinion slightly pointed at the transfer. I even checked the slop in the front shaft and seems to be pretty tight. In my opinion and if I could do it over again I would not have bought the IRO I do not care for the washer setup in the center as it seems it could eventually come unglued.

95and97XJinWI

I just did a Rustys 6.5 inch lift and a IRO hnt 6 degree shim in the rear and a stock front driveshaft. I have no vibes at all. Im roling on 33's stock gears plenty of power

TheNerd

Looks can be deceiving. Did you measure your angles with an actual angle finder (or some other tool), or are you just eyeballin' it? 1-2 degrees is certianly not something that I can eyeball, and I don't think geometry really takes opinions into account...

beerdriver1

Well lets put it this way, when I first did the lift I installed 6* shims!! It actually put the pinion higher than the parellel drivshaft but I ran it anyway for a few weeks till I had time to install smaller ones. Once I installed smaller ones(3*) it hardly changed anything at all for vibes if anything worse!! So I have now decided that pinion angles make alittle difference but not too much. When I first installed the HNT I didnt cut the pinion and it was resting on the coller of the shaft. I drove it and wow serious vibes. I brought it back to the shop and then cut down the pinion so it was nice and flush on the shaft and away from the collar. I drove it again and much better but small vibes just in all speeds under throttle only! If I let off they go away.....

helmut

You should really take your front driveshaft and put it on the rear. Maybe your dshaft is not balanced. Its the easiest thing to rule out and take it from there. For all its worth I also have the IRO HNT and no vibes at all, very satisfied. Its on a 4.5 with 4degree shims and relocators but to have the perfect angle I would have to swap to 2degree. Either way still no vibes so x2 on the pinion angle. With an hnt sye I dont think a few degrees would give you vibes. But then again, who knows. I know that I have no vibes with or without the shims.

grizbomb

Dumb question what's iro?

Scott0821

Iron rock offroad

lgnut123

I did the IRO hack n tap on my 4.5" and it solved all my vibes.

Just make a checklist

U-Joints
Angle of rear yoke
Make sure the bolt into the output shaft is loc-tighted on nice n good as well as everything else
Although the driveshaft is a refurb it could have balance issues... unlikely
Wheels balanced?

If everything LOOKS good then try out your front drive shaft back there. See what happens.

Stupid question but is the hole you drilled dead center and straight? Someones gotta ask...

pickles

Just ordered an IRO hack n tap today. Got my invoice and they made a mistake on the parts I asked for

So hopefully when it gets sorted out and I do receive it that I have no vibration problems