INSTALLED ROVERTYM 2" LIFT.....VIBRATION CONCERNS!

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Top of pagePrevious messageNext messageBottom of pageLink to this message   By ERIK on Tuesday, April 24, 2001 - 09:33 pm: Edit

INSTALLED LIFT SUNDAY, NOW HAVE VIBRATIONS UPON ACCELERATION AND AT DEACCERATION FOR ONLY A SECOND AS GEARMESH LOAD AND UNLOAD, LIKE I SAID ONLY FOR SECOND, DOESN'T FEEL OR SOUND GOOD,AT SPEEDS 60 AND ABOVE, NO VIBRATION AT SPEED.

LOOKING FOR INPUT
THANKS ERIK

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Kyle Van Tassel (Kyle) on Tuesday, April 24, 2001 - 09:45 pm: Edit

That vib seems to be the thing here lately. I have heard of different attempts to fix without any luck. Try a Front driveshaft for starters.

Kyle

Top of pagePrevious messageNext messageBottom of pageLink to this message   By MarkII on Tuesday, April 24, 2001 - 10:25 pm: Edit

Just posted this for the message above. I had just about given up hope but in the end it shows you just gotta try everything once. I do have the "CV" jointed front drive shaft but I don't have a nice bumper/winch hanging off the front either so my lift works out to be a little taller than 2" since John designed it with that in mind. Good luck.

I just added a lift and noticed loads of vibes between 40-50 and 60-70. Yanked on everything under the truck to find out if anything was loose - nothing. Tonight I decided to pull the rear shaft just to test - bingo! The nuts on the tranny side were just over finger tight. Tightened them up - no more vibe. Check it out. Just yanking on the shaft might not be enough (as in my case). Try a wrench on it to see if you can tighten any of the 16 bolts on the 2 drive shafts. You also might just want to pull them 1 at a time like I did. Found a U-joint on the front that was giving up the ghost as well.

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Ron on Wednesday, April 25, 2001 - 09:02 am: Edit

Pull shafts to isolate which one it is. ie pull front, drive with dif locked see if there is a vibe. Then put front back on and pull rear. That gets you to front or rear causing vib. Then check tightness in bolts, play in U-joints, and finally play in output shafts on T-box. Let us know how it goes.

Ron

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Kyle Van Tassel (Kyle) on Wednesday, April 25, 2001 - 10:13 am: Edit

Thats not completely accurate Ron as there are all kinds of strange loads that go on when both shafts are in. That can give you a false diagnosis.

Kyle

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Ron on Wednesday, April 25, 2001 - 10:29 am: Edit

From what I have gathered lift related vibs have come from:

1). Bad u-joints/wear in U joints/bad rotoflex
2). Loose bolts
3). Play in T-box
4). Excessive drive shaft angle

If the vibe is new with the lift I would say in 99% of cases 1-4 cover it. with 2in of lift he should no yet be into #4, so he should look for the obvious before spending real money on the problem. A cv front drive shaft will mask worn T box output shafts and eliminate the vibe, but it will not "solve the problem." Since it reduces the load on the t-box shaft it will probably extend life there but if it is already worn (and leaking or soon to be leaking) then maybe the solution is to fix it and do the cv shaft.

Ron

PS what "strange loads" are you referring to? I would say in most cases (unless it is multiple problems like Mark had) the pull each one will wind the problem.

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Kyle Van Tassel (Kyle) on Wednesday, April 25, 2001 - 10:50 am: Edit

Man , its a strange area. If you pull the rear or front shaft and lock the box to drive it. You have changed the conditions of the test. Most of the time you will find you can pull either shaft and the vib gos away. (Referring to these annoying little ones that are cropping up lately). The reason I recomend the front shaft is not really because of the joints but more about the slip yoke. Its slightly extended now and is more then likely causing some vibbing. HE can check it by pushing the shaft up and down at the joint. I am sure he will find some play.

Kyle

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Ron on Wednesday, April 25, 2001 - 10:53 am: Edit

Worn bearing or whatever it is on the front of the T-box right? Thats why I say the cv shaft won't "fix" the problem and that maybe the correct thing to do is to fix the box and install a cv shaft. Personally I would just live with it unless it gets bad enough that you think it is going to throw the shaft through the floorboard.

Ron

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Ron on Wednesday, April 25, 2001 - 10:54 am: Edit

what I don't get Kyle is why my method would not detect the problem, are you saying pulling the rear shaft would cause a vib caused by the front shaft to go away? Still trying to learn as much as I can.

Ron

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Kyle Van Tassel (Kyle) on Wednesday, April 25, 2001 - 11:45 am: Edit

I am not saying it wont give you any data. It just might not give you good data and might lead you in a bad direction. You have to keep in mind the crap thats between those drive shafts and how the load changes on them when there is just one installed V.S two. There is a whole set of spiders and bearins and all kinds of crap that would just love to vibrate. The vibrations this guy is reffering to are gone under load. I am hearing it more and mroe these days and actually have tangled with it myself.

Kyle

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Milan on Wednesday, April 25, 2001 - 11:51 am: Edit

Ron,
I think that's the possibility Kyle is refering to, though I'll let him speak to that. Taking the working load off one end and/or adding it to the other can lead to the problem getting worse or actually disappearing.

I had an identical problem on my Jeep. When I'd take the rear shaft out, the problem would still be there seemingly coming from the front. When I put it back in, it felt like coming from the rear. This would point to the T-case rather than driveshafts, but the t-case checked out OK (plus it's fairly new Atlas II - so I'd expect the driveshafts to go before the output bearings ever give up). Rebuilding the rear driveshaft (CV on the t-case end) did not seem to help either. Diff pinion bearings are tights, so, now I'm looking into the angles.

I still think that removing the shafts is a good way to start in all the cases because it will isolate obvious problems like stated above. Just in those wierd cases you will then end up having to search elsewhere.

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Kyle Van Tassel (Kyle) on Wednesday, April 25, 2001 - 12:09 pm: Edit

Yes Milan , and the vibration this guy is talking about I am sure is going to be one of those cases. I get mail pretty often on the very same thing.


Kyle

Top of pagePrevious messageNext messageBottom of pageLink to this message   By JEEPETR on Wednesday, April 25, 2001 - 12:14 pm: Edit

Sometimes I really hate this new message Board. I Just posted a long reply with help for you ERIK, but its gone, said it posted, but not here...
and its not the first time!

Anyway, check out this, I have a feeling this is what you are experiencing...

www.whiterover.com/resources/D90RearArms.html

Scott T.
'95 D-90 (JEEPETR)
'96 Discovery (New addition to the Addiction!)

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Ron on Wednesday, April 25, 2001 - 12:15 pm: Edit

What do you think it is? I have always heard that the bearings and sometimes spline on the output shafts of the tbox wear and cause this. Diagnosed by play at the output shaft and even leaks there. I don't know if it can be fixed in situ or the box has to come out.

Vibes smhibes is my feeling.

Cheers
Ron

Figure I better learn how to rebuild all these things sooner or later

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Ron on Wednesday, April 25, 2001 - 12:22 pm: Edit

Keith so you are saying it is the driveshaft angle at the dif pinion or at the t-box? The former does not make too much sense. The latter I can see an would say it is wear related and the shortened arms just reduced stress on it eliminating the vibe.

Ron

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Kyle Van Tassel (Kyle) on Wednesday, April 25, 2001 - 12:25 pm: Edit

What scott just posted there is a good start. I have hear of success with that as well. I think the problem is there are so many different issues under there its hard to tell when you have eliminated one. You do something and yes , maybe it did take care of one issue , but you still have a vibe , so you second guess yourself or the part that you modified and then the paradox begins... :)

Kyle

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Tom on Wednesday, April 25, 2001 - 01:17 pm: Edit

Odd that the solution over on the d-90 board is to shorten the rear links. I have the 3" kit from RT and have spacers installed to lengthen the links, and I have some vibes. I thought it was because of my rear DS being screwed up because there were no vibes when I tested with it off. I guess the next test is to remove some spacers, one by one, and see if the vibes go away?

Thanks for the insight.

Tom

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Ron on Wednesday, April 25, 2001 - 01:27 pm: Edit

Be carefull if you shorten the rear links it will pull the axle and tires forward and you don't want to trim the door. If this really is the solution I will be suprised.

Top of pagePrevious messageNext messageBottom of pageLink to this message   By JEEPETR on Wednesday, April 25, 2001 - 01:48 pm: Edit

Hey Tom,

I'd try taking a spacer out If I were you. I know the design of the RoverTym arms, but I was always suspect of whether you were suppose to add spacers for lift, or delete them for a lift. You might wana call John at Rover Tym and ask...

Ron,

Shortening the trailing arms won't move the axle forward (no more than the lift already did), because it is located in the center by the upper a-arm and ball joint. It will in effect rotate the axle housing clockwise (if viewed from the drivers side), moving the pinion upward. Yes, the wheel moves forward when the axle drops, and it is due to the effective shortening of the trailing arm, but when it articulates, the arm on one side effectively shortens, and the arm on the other effectively lengthens. This creates a pivot point around the center A-Arm ball joint, and the wheel actually moves forward or backward (depending upon side) in this instance. When the trailing arms are shortened, but the position of the Upper a-arm stays the same, the axle rotates. Lifting the truck will actually move the axle forward, as not only does the effective length of the trailing arms change, so does the effective length of the upper A-Arm.... Geez, I hope everyone can understand my babbling...

~Scott T.
'95 D-90 (JEEPETR)
'96 Discovery (New addition to the Addiction!)

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Kyle Van Tassel (Kyle) on Wednesday, April 25, 2001 - 01:55 pm: Edit

Wrong Scott , if you remove those spacers its HELLO DOORS!! If you are running some decent sized tires. Ron , this method has had an affect on the vibs in several trucks already , along with the one that Scott posted the link to.

Kyle

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Ron on Wednesday, April 25, 2001 - 02:36 pm: Edit

Scott,
I understand what is there but I thought (within a given range) that the wheelbase (ie the front to back position of the axle) was most controlled by the length of the arms and not the a frame.

Kyle,

I can see how it would help with dif pinion related problems and I guess kinda sorta how it would do the same thing as a lengthened drive shaft would with the dif angle.

All who are reading,
I would say try to find out where the problem is before you go buying shit or cutting crap or anything like that. I am of the opinion that unless you have wear or play a rover should be able to take 2in ith no vibes BUT at that level you are going to eat u joints and put extra stress and wear on the output shafts of the t-box. Personally, there are NO vibes in the 88 rangie with OME HD and no extra weight, why you ask? I bet it is because the T-box is new and the u-joints are fresh. The disco has some vibes but I belive it is tire related, besides that thing is so heavy that the lift is not that great.

Cheers and best regards to all,
Ron

Vibes smchibes

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Tom on Wednesday, April 25, 2001 - 02:49 pm: Edit

I am going to try dropping a spacer and see the effect this weekend. Luckily I have access to a forklift and can see the impact on the doors. I'll keep everyone posted.

Top of pagePrevious messageNext messageBottom of pageLink to this message   By John on Wednesday, April 25, 2001 - 04:11 pm: Edit

Understanding rear trailing arm spacers......
Lift your suspension, the diff rolls up....because the a arm is fixed....and the rear links are fixed to the frame....lift the frame, the diff(pinion angle) rolls up. So you have disturbed the therotical 3 degree std. pinion angle and moved the tire closer to the door as well. Adding a combination of spacers until you achieve the theretical 3 degree pinion angle to match the TC case angle will put your drive shaft back to its original position to take away the drive line(u joint) oblong rotation that creates the vibs. Tire to door clearance is improved but thats a tire size issue to consider as drive line is most important in the pecking order. Hope this helps.

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Tom on Wednesday, April 25, 2001 - 04:47 pm: Edit

John -

Since my effective lift is actually a bit greater than 3" due to my lack of bumpers/sliders, is it possible that i may need additional spacers, rather than less?

Hopefully i didn't totally miss your point.

Tom

Top of pagePrevious messageNext messageBottom of pageLink to this message   By John on Wednesday, April 25, 2001 - 05:06 pm: Edit

With a magnetic protractor, measure your diff angle off the bottom of the flat on the diff bottom..it should show about a 3 degree up angle.
Work from that....the other option is without sliders, winch...etc the angle may be too sharp at the TC case. After checking the 3 degree angle...throw 3/4 hundred pounds of weight in the rear, adding weight(lowering truck) and see what that says.

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Tom on Wednesday, April 25, 2001 - 08:40 pm: Edit

Thanks, John...I have my homework assignment for the weekend!

Tom

Top of pagePrevious messageNext messageBottom of pageLink to this message   By JEEPETR on Thursday, April 26, 2001 - 10:32 am: Edit

Hey All,

At this point I should probably keep my mouth shut, but go ahead and correct me again if you folks feel I'm wrong. John, I have questions about "Restoring" the pinion angle. Yes, lifting does already rotate the pinion upward, but it does not seem that it rotates it enough to keep the driveshaft to pinion angle within tolerance, hence the "Garunking" noise and vibrations. Rotating the pinion back down to a factory "3 degrees" would simply increase the angle between the driveshaft and pinion, taking it even further out of tolerance, increasing (I would think) the likelihood of vibrations. You know what, never mind, I am done with this discussion, you guys fight it out, I'm just sharing what I've learned in my years of Modifying these Beasts (mostly D-90's I admit)....

Humbly yours Everyone,

Scott T.
'95 D-90 (JEEPETR)
'96 Discovery (New addition to the Addiction!)

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Kyle Van Tassel (Kyle) on Thursday, April 26, 2001 - 11:02 am: Edit

Scott , man , speak up , it dont matter. And what you are saying does make sense yes. But , both should be at the same angle , if the transfer case is sticking down at a 3 then the pinion should be a 3 as well (Actually anthing between 3 and 4 should be ok)
Now , anyone that has spent enough time working on cars understands that this can go out the window at any given moment , its just a good starting point.
Its sort of like a setting up gears , pinions are supposed to be set at a certain depth that is predetermined , that rarely ends up being the case all said and done. Yous et the things up so they work and the same thing gos with anything else.

Top of pagePrevious messageNext messageBottom of pageLink to this message   By John on Thursday, April 26, 2001 - 11:46 am: Edit

Both should be at the same angle until you reach the point of too severe a u joint angle....at that time its the opposite direction for the CV driveshaft set up.Basically on this thread we are speaking in the confines of 2/3" lifts which normally are in working limits on the longer rear shaft.Good debate/conversation makes for good answers I feel.

Top of pagePrevious messageNext messageBottom of pageLink to this message   By IHC Scout on Friday, April 27, 2001 - 10:14 am: Edit

I agree with John, Both angles on the rear shaft must be the same or within a degree or two. This is for a standard 2 ujoint shaft. If you have a CV, the pinion must be rotated up so that it is nearly the same angle as the shaft (not exactly though, it needs some angle (1-3 degrees)).

Adding spacers to the rear links effectively turns the pinion downward. This is done to keep the pinion angle nearly the same as the tcase angle. This is done assuming you have a standard 2 ujoint shaft.

Top of pagePrevious messageNext messageBottom of pageLink to this message   By Ron on Monday, April 30, 2001 - 01:44 pm: Edit

So now that we hav confused the heck out of the poor chap asking this question I go back to my original point which is that he should NOT have vibes with a 2in lift on a stock set up that is within spec. So check the u joints and check for play at the difs and at the T-box, then pull the shafts and see where it takes you. If you are still lost after you do all that, then try all the other stuff out there. But I am willing to bet dollars to donuts that you will find something is wrong that will eliminate the vibes you are having when fixed. I am also will to place money on wear at the T box being the culprit.

Ron


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