Driveline Vibes - searched!

[pierceME311]

Just found this for sale part. It's an AA HD sye for $150, new and never installed. That's a deal and a half. and not much more than a RE hack-n-tap.

http://www.naxja.org/forum/showthread.php?t=932712

 

[selarep]

Just found this for sale part. It's an AA HD sye for $150, new and never installed. That's a deal and a half. and not much more than a RE hack-n-tap.

http://www.naxja.org/forum/showthread.php?t=932712

if you read that whole post, you would have seen it was sold already.

 

[yossarian19]

Guess I shoulda been more clear - SYE ain't happening if I can avoid it. I know its the best, but then, there ain't money for it...
EDIT: I think I've got all the info I need now - just had to find one more piece and the whole puzzle cleared up. Thanks for all your help, folks, and I'll let you know how it turns out!

 

[billy heal]

aright well ill tell ya what i have but i may have just got lucky..lol ive got 5 inches of lift on my xj with a 1.5 inch tc drop and no viberations.. i did replace both motormounts the right side actually broke all the studs off in the block.. it was about time for them to go tho 13000 miles stuff will start wearing..lol

 

[WholeLottaXJ]

I have all the pieces to a Hack n Tap minus a front driveshaft that I could let go for cheap. I have the flange and also Spicer part #211229x. Let me know.

 

[Rod Knee]

Get one, then measure the angle of the pinion and then the t/c output shaft. The output shaft and pinion shaft should be within 2*-3* of each other.

I recently did a 2 inch "budget" lift. After the lift I noticed some very mild vibes that correspond with a low pitched growl at 35-45 mph. My mechanic says I just have tire noise. The fact that I have these effects on pavement but not on loose gravel seems to corroborate his opinion. On the other hand, I did not have these effects at all before the lift. So the jury is still out on this issue.

Last night I measured my OP shaft and pinion shaft as being within 2 degrees of each other, within your tolerance limit. So would shimming 2 degrees to get the pinion a bit down be a waste of time, or would it potentially be of benefit? I don't want to lengthen the distance, however slightly, between TC OP shaft and pinion if there's no benefit in doing so.

 

[Rod Knee]

So would shimming 2 degrees to get the pinion a bit down be a waste of time, or would it potentially be of benefit? I don't want to lengthen the distance, however slightly, between TC OP shaft and pinion if there's no benefit in doing so.

That Q. is open to comment from anyone btw.

 

[yossarian19]

From what I've gathered, in this post thread and others, you want your pinion to be 3* lower than parallel to your tcase.
SO: If your tcase is at 2* up, parallel would be 2* down at the pinion, ideal would be 5* down.
This 3* down bit is because under acceleration the drive torque makes the pinion angle rise about 3* - or close enough. If you angle it parallel (which is where a double u-joint shaft wants to be) then the torque twists your pinion angle UP, causing vibes.
I've also heard "just put the joints in parallel, works well for me" and "1* is plenty"

A starting place is to make your tcase and axle pinion angles equal but opposite. 1* up at tcase, 1* down at pinion. Drive it, check it out. If it works, leave it alone. If it buzzs, angle pinion down.

 

[Rod Knee]

From what I've gathered, in this post thread and others, you want your pinion to be 3* lower than parallel to your tcase.
SO: If your tcase is at 2* up, parallel would be 2* down at the pinion, ideal would be 5* down.
This 3* down bit is because under acceleration the drive torque makes the pinion angle rise about 3* - or close enough. If you angle it parallel (which is where a double u-joint shaft wants to be) then the torque twists your pinion angle UP, causing vibes.
I've also heard "just put the joints in parallel, works well for me" and "1* is plenty"

A starting place is to make your tcase and axle pinion angles equal but opposite. 1* up at tcase, 1* down at pinion. Drive it, check it out. If it works, leave it alone. If it buzzs, angle pinion down.

I should clarify that I do NOT have a double cardan, I'm not sure if you are talking about double or single cardan. To be parallel, both pinion and tcase output shaft should give the same reading, unless I'm missing something. Not sure where your 3 degrees down bit comes from, I haven't gotten that out of anything I've read.

On my inclined driveway my pinion is oriented 9 degrees from horizontal and my TC OP shaft is at 7 degrees in the same direction. So my pinion is "sticking up" 2 degrees off parallel with my TC OP shaft. I need to shim it down 2 degrees, unless I'm missing something or not understanding these angles corrrectly, if simply being within the stated tolerance limit of 2 to 3 degrees is unsatisfactory.

 

[TNT]

From what I've gathered, in this post thread and others, you want your pinion to be 3* lower than parallel to your tcase.
SO: If your tcase is at 2* up, parallel would be 2* down at the pinion, ideal would be 5* down.
This 3* down bit is because under acceleration the drive torque makes the pinion angle rise about 3* - or close enough. If you angle it parallel (which is where a double u-joint shaft wants to be) then the torque twists your pinion angle UP, causing vibes.
I've also heard "just put the joints in parallel, works well for me" and "1* is plenty"

A starting place is to make your tcase and axle pinion angles equal but opposite. 1* up at tcase, 1* down at pinion. Drive it, check it out. If it works, leave it alone. If it buzzs, angle pinion down.

The below info applies to rear driveshafts only.

With a stock type shaft this is how I do it
I set my pinion angle 1-1.5 degree lower then the transfer case angle.
Example transfer case angles 5 degrees down the pinion wout be set at 3.5 to 4 degrees up. I try to keep a 1 degree difference.
I keep the angle this close because at higher lifts a 2 degree difference will cause vibrations when cruising.
Set at a 1 degree angle difference I have put 40,000 miles on a shaft that has a 15 degree operating angle on level ground. The u-joints are still tight and good to go.
I also use sealed Spicer u-joints that I regrease with good grease.

With a SYE I set the pinion 1-2 degrees less then the driveshaft angle.
Example - driveshaft angle is 12 degrees down the pinion would angle up 10-10.5 degrees up. I try for a 1.5 - 2 degree difference.

These setups work great for me. I always use a synthetic extreme pressure grease. I clean all of the grease off of the new Spicer u-joints and regrease them with the good stuff.

I use this grease for everything that get greased on my rig.

 

[TNT]

On my inclined driveway my pinion is oriented 9 degrees from horizontal and my TC OP shaft is at 7 degrees in the same direction. So my pinion is "sticking up" 2 degrees off parallel with my TC OP shaft. I need to shim it down 2 degrees, unless I'm missing something or not understanding these angles corrrectly, if simply being within the stated tolerance limit of 2 to 3 degrees is unsatisfactory.

Shim it 3 degrees down, that would be my plan.

 

[Rod Knee]

Shim it 3 degrees down, that would be my plan.

Thanx for that input. As it turns out, 3 degrees is the lowest angle shim I can find in steel anyway.

 

[XJ AV8R]

You can find smaller ones...

 

[yossarian19]

Av8er - you a Ft. Louis guy? I used to live in Olympia, just down Capital blvd from Tumwater. Heck of an area, might go back there when I get my EMT

 

[XJ AV8R]

Cool! I live in Tumwater near Briggs Nursery at Yelm Hwy and Henderson...at least it used to be Briggs Nursery. I'm not a Ft. Lewis guy but I currently fly for Alaska Airlines out of Sea-Tac. I love the northwest too. I just got back from Capitol Forest 10 minutes ago. I took the Jeep but had mountain bikes on the back of it this time. No wheelin'...didn't want to rip off the bikes! We got snowed on at the top of Capitol Peak. There was probably 2 inches on the ground at the deepest part, so not much, but it's coming. All of this, and only 35 minutes away...gotta love it! Where are you now and how long have you been gone?

 

[yossarian19]

Cool! I live in Tumwater near Briggs Nursery at Yelm Hwy and Henderson...at least it used to be Briggs Nursery. I'm not a Ft. Lewis guy but I currently fly for Alaska Airlines out of Sea-Tac. I love the northwest too. I just got back from Capitol Forest 10 minutes ago. I took the Jeep but had mountain bikes on the back of it this time. No wheelin'...didn't want to rip off the bikes! We got snowed on at the top of Capitol Peak. There was probably 2 inches on the ground at the deepest part, so not much, but it's coming. All of this, and only 35 minutes away...gotta love it! Where are you now and how long have you been gone?

Capital forest is a gorgeous spot. Only been there once or twice - avoided the place after we lost an Evergreen student back there.
The NW though is amazing and Olympia area in particular. Mt Rainier, Seattle, Portland, the San Juans, Olympic national park.... Dang, I miss that place.
I went to Evergreen for a couple of years and lived all over Olympia. Stayed for a while after graduating but when student loan money ran out I had to go get a job, and the outfit I wanted to work for happened to be in UT. So here I am in SLC *ugh* but if the world is a perfect place I'll get my EMT and move back in the next 6 months.