Drive line vibrations

[Mudderoy]

I've had drive line vibrations off and on ever since I lifted the 98 Cherokee. Recently I installed a Tom Woods SYE and I wouldn't say the vibrations were the worst I've had but I did expect it to be smoother.

I may have found out the issue and even may have remembered(?) something that Rough Country had in one of their install manuals(?)

The RC 4.5" Leaf springs come with shims attached. From my guestimation they look to be 6 degree shims. Well I'm thinking that this is fine for a stock drive line lift installation, but perhaps the shim is meant to be removed for a SYE drive line.

Here is where my pinion was pointing, now keep in mind this is the RC 4.5" leaves, the RC 6.5" shackles (total lift, not 6.5" long). And I recently added the Ironman4x4fab.com Shackle Relocation Brackets. Now I think the lift is where a new RC 6.5" lift would be but I just have my guesses on this, since my 4.5" lift is about 5 years old. I'll say this though. The 5 year old leaves and shackles were not producing a NEW RC 6.5" lift. (I guess that shouldn't be expected).

2604

Removing the RC shims wouldn't have been too bad if the u-bolts weren't too long to get a socket on it and the nuts, with the plastic inserts weren't so stubborn. Lots of 3/4" combo wrench work...

2607

2605

2608

2609

And based on something Matt noticed I happened to think of checking mine. This is the C8.25 yoke and as you can see the u-joint has quite a bit of room to the stop.

2606

[4.3LXJ]

Tony can I see a pic of the pinion with the driveline installed?

[Mudderoy]

Tony can I see a pic of the pinion with the driveline installed?

Yeah damn Internet went down while I was doing this post, I'm going to edit and finish it up now.

[Mudderoy]

See updated original post!

It was weird. As soon as I backed out of the driveway and started down the street everything felt really really smooth! Could this just be my imagination? Wishful thinking? It reminded me of the feeling when I first drove out of Discount Tires with my new set of KM2s.

As I got out to the main road and sped up to 40 mph, still smooth. I recently adjusted my steering box back (had tightened it because of the drift on the road I was having) so steering was easy and the ride was notably smoother.

After a while I was able to get to a stretch of road where I was able to get to 60 mph. Around 50 mph I "heard" a slight rattle from my a-pillar gauge mount. A typical thing I hear at this speed range. However it wasn't very loud. So there are still vibrations, but no where it used to be.

After a solid week of radiator and coolant temp level testing, it may be time for a highway test. It will be interesting to see what coolant temps and vibrations are at 70 to 80 mph.

[XJ Wheeler]

Tony, off topic and i don't mean to call ya out or anything. But, is that jackstand meant to support the vehicle or just hold the spring?

2610

[Mudderoy]

Tony, off topic and i don't mean to call ya out or anything. But, is that jackstand meant to support the vehicle or just hold the spring?

2610

Without the jack stand the leaf spring would drop down. This way it helps hold the leaves together and keeps the spring in one place as I drop the axle to remove the centering bolt. Short answer; No

There was a high lift on the slider, a jack stand just in front of that leaf and of course the hydraulic jack under the rear diff. Also, there were wheel chocks on the front wheels, one in front of one wheel, and one in back of the second. Transmission was in neutral as was the transfer case so I could remove the driveshaft.

[Mudderoy]

Just ordered one of these from http://ironrockoffroad.com/ to address the gap between the u-joint and the factory original yoke.

http://www.ironrockoffroad.com/Merchant2/C825uboltyoke1.jpg

:link: (http://www.ironrockoffroad.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=IROR&Product_Code=IR-XC825Y&Category_Code=)

[XJ Wheeler]

Without the jack stand the leaf spring would drop down. This way it helps hold the leaves together and keeps the spring in one place as I drop the axle to remove the centering bolt. Short answer; No

There was a high lift on the slider, a jack stand just in front of that leaf and of course the hydraulic jack under the rear diff. Also, there were wheel chocks on the front wheels, one in front of one wheel, and one in back of the second. Transmission was in neutral as was the transfer case so I could remove the driveshaft.

Just looking out for ya safety. ;) Good job.

And just so everyone knows, jacking or supporting the vehicle by the spring is a NO-NO.

[Mudderoy]

Even if it doesn't improve drive line vibrations, it will improve my piece of mind that the drive shaft will stay attached to the yoke!

2685

:link: (http://www.ironrockoffroad.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=IROR&Product_Code=IR-XC825Y&Category_Code=)

This one is for the Chrysler 8.25, Dana 30 will be next sometime in the future. :D

[Carves]

Even if it doesn't improve drive line vibrations, it will improve my piece of mind that the drive shaft will stay attached to the yoke!


ohhhh ... get away .. :poke: ... You just wanted the decal .. :p

:D


Do they sell the U-Bolts separate as replacement parts/spares ??

[Dredwolf]

Even if it doesn't improve drive line vibrations, it will improve my piece of mind that the drive shaft will stay attached to the yoke!

2685

:link: (http://www.ironrockoffroad.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=IROR&Product_Code=IR-XC825Y&Category_Code=)

This one is for the Chrysler 8.25, Dana 30 will be next sometime in the future. :D

Keep us posted, I have looked at this several times...

[Mudderoy]

Okay I've been a little nervous (never done it before) in replacing the yoke on the Chrysler 8.25. I was fine with what msmoorenburg told me but I had to mess that up and go off searching on Google. I read a bunch of stuff having to do with crushing the crush sleeve too much and messing up the ring and pinion. Not re-using the pinion nut, oh and ALWAYS replace the seal.

I had to ask Matt about these things, and he bitch slapped me and told me to stop my whining and go change the damn yoke already! Actually he answered all my questions and quelled my fears, but I could tell he wanted to do the bitch slap thing! :smiley-laughing021:

2969

2970

2971

2972

2973

2974

2975

2976

Those U-BOLTS looks so much more secure than those crappy straps. Also I didn't know until recently you're not supposed to reuse the straps. :sad0147:

[Mudderoy]

I remember years ago when I worked in the Westchase area I would drive the beltway to and from work. Now Beltway 8 is called the Houston autobahn. If you're doing 80 mph you better be in the slow lane. My stock red Jeep was plenty fast enough to be the local group leader on the Beltway. I remember winding up that 4.0 like no body's business.

One thing I noticed was during heavy acceleration usually in excess of 70 mph the rear view mirror would vibrate. Nothing Linda Blair possession shacking just a nice cool effect, of course I couldn't just sit there and enjoy the view, at that speed.

After many of the modifications slowly, I suspect, that mirror vibration became and all the time thing. This is my first Cherokee to modify so as far as I know this is part of what you have to endure, pay to play so to speak.

It wasn't until Matt start building up his 97 and complaining about the vibrations that I learned different. On Matt's recommendation I have replaced the yoke (post above). Well today was my first day to drive my 98 with the new yoke installed. As I told Matt on Google+ chat, it's so smooth I fell asleep twice on the way to work!

The days of the constant mirror vibration, well above 35 mph, seem to be gone.

If you are putting up with vibrations, you can do something about it.

Now I want to understand why the factory yoke developed a gap between the tabs that should have been flush against the u-joint. As I thought of this driving into work, between naps, I wondered if drive line vibrations may have caused a hammering of those tabs from the u-joint and slowly over time making a gap wider and wider.

Don't know, just thinking as to how it could have happened.

[reddragon72]

before I replaced my yoke with a dealer yoke that is 3/4 inch's longer I had the same play. The stock yokes seem to wear over the years. After my change I noticed all rear vibs were gone.

To this day no vibs from the drivetrain just that incisive front wobble. Need to get a balance and then adjust the lowers to bring in the pinion up a tad and hope that helps the wonders and wobble.

But so far I have been lucky on the vibs, especially after putting in the longer rear yoke.

[NW99XJ]

I for a long time have thought that vibes are just a part of this whole thing we call Jeep Building, and just like Tony said, it's "part of what we have to endure" when lifting, going with bigger more aggressive tires, etc. After I completed stage-1 of my own lift (3") I noticed driveline vibrations.... first freeway speed test I remember them coming on and thinking to myself... "OH! ...that must be what they call driveline vibes"...... A T-Case drop came very soon after as my leaf packs were already shimmed. Now after I put in a SYE, all that went away.,.....for the most part. Now its been a little bit since I've driven the Jeep, but this whole thread has me thinking that I'll be paying WAAAY more attention to the what/where from/and how much vibrations that I have probably "just gotten used to" over the years are doing.....
I'm a firm believer of the strength of the U-Bolts vs. Straps to begin with, but I've wheeled pretty hard, and the straps have never failed me yet (knock on wood) ....putting this mod off has been more of a want vs. need sort of thing.

[Mudderoy]

Some gratuitous pictures of D30 drive line angles...

3035

3036

3037

[98FloridaXJ]

I was looking for this episode on the podcast and have been searching the forum. Just did a 4.5-5 lift and I'm getting vibes. Just received my rugged ridge sye and was planning on picking up a front driveshaft at the jy this week. Two questions: do I remove my TC drop when I do my sye and will I need shims? Loving my xj on 33's and have other things on the to do list but this is my priority right now.

[4.3LXJ]

Yes to both. I have a thread here in the tech section entitled how to set driveline pinion angles

Sent from my DROIDX using Tapatalk 2

[NW99XJ]

Yes to both. I have a thread here in the tech section entitled how to set driveline pinion angles
Said thread can be seen here: http://www.xjtalk.com/showthread.php?t=7299&highlight=pinion+angle