prior to my issues I was running a set of 219 lb/in springs and 1 3/4" spacers with everything else stock and a set of old RS5000's ... no issues what so ever hit any hole at speed, 120kph+ without issue.
Do the WJ swap, replaced wheel Ball Joints, Unit Bearings, all new TRE's and DRE's (1-tons) the axle was rebuilt with the regear in September, literally the front end is new disk to disk. the only real change besides the whole WJ knuckle thing ... was the swap to the RE springs with the 164 lb/in rate. Been doing my homework on spring rates and dampening.
I can drive at any speed over normal roadways, but when i get into the really chopped up cracked roads (and I mean like 3" deep potholes, and whole dropped sections of pavement and the like) is when I have my "issues". If I just did normal city driving I'd never even know I had issues. It's only because i happen to work down one of the crappiest 148km sections of highway BC has to offer that I even found out I had the issue.
a major indication of improper dampening is ongoing wheel hop, usually associated with multiple bump hits at speed. I already have the stiffer springs so it's a route I'm going to try ... really what do I have to lose. Or I can likely go buy the shocks valved for these springs,
the problem is my springs aren't fighting anything, my shocks are valved for a stiffer spring rate. Matching them up may solve the issue if the the issue is wheel hop.
To be clear this isn't a vibration, isn't a shake, or a simple shimmy ...
this is a bump above a certain speed, that set off a chain reaction ... with the initial hit I get a shake in the front end, then just as you would expect a normal suspension to dampen the hit, mine goes into overdrive and it's is literally like it shifts a gear and goes apeshit. with everything I've done so far I've gone from standing on the brakes holding on for dear life while listening to my wheels squeal as my front end bounces off the road (yes, I hear it do so, chirp, chirp, chirp as I come to a stop) to now I just need to hold the brakes and whiles it's still bouncing there is no more side to side movement and the vehicle even tracs staright while bouncing. Even before there was very little side to side movement even in the steering wheel. From what I felt, the only side to side movement was due to the trac bar doing what it is supposed to and as it is a fixed length, going up will push the wheel one way and going back down will push it the other, simple as that. It was never the wobbling wheel of death type wobble but the pogo stick dance from hell more so.
There was far more movement in the wheel and axle when the tracbar was it's original 9" shorter than the drag link. But, now that it's completely parallel to, and only 3" shorter than the drag link, there is almost nothing felt as far as sidie to side turning movements. What I do feel is more just a vibration of the steering column associated to being attached to a front end gone cracktasticly insane.
If I were to remove the shocks, the spring will bounce uncontrollably until I stop, at ~70kph I get a series of bumps from a deep pothole quite similar to blown shocks. 4-6 bounces as it were. When going over a simple speed bump my front end is marshmellow soft and I a soft plush bump in the front and the typical jeep ride in the rear.
Before the WJ swap, with the stock steering stretched to it's limit, and all arms exactly the same as they are now but with slightly stiffer springs ... I got a bump pretty close to stock on the highway over potholes, and the 6 speedbumps in my Cul-de-sac (and that works out to one every 150' FYI). This is with the same Rancho shocks I first used after the WJ swap with the softer springs and initially with no SS mind you (it was added after my first trip to work when, after driving for 4 days without issue I finally hit the 'right' stretch of road).
I'll stop there ... It's just so frigging frustrating really ... even trying to research Death Wobble is misleading as a lot of out of balance tires, and worn u-joints, and driveshaft vibration get called DW when anyone who has actually experienced true DW knows it isn't. Hell I can deal with vibrations that's easy and simple by comparison to this. I mean I can drive 110kph down the highway trouble free for miles, and then there is that one special bump, or series of bumps and Blammo it all goes to hell. And then once I stop it's all cream pies and buttercups again until I hit that one magic bump or series of bumps ... and BLAMMO ... "holy hell I need new undies, dear god I forgot to tell the wife I love her, please don't let me die!" until I stop and then it's all roses and cupcakes until I hit ... you get the idea. Problem is there are no stretches of hellishness within 150kms of me to find out if I've fixed things. So, each shift home I make it drive better (I mean this XJ handles a gazillion times better than my wife's 2008 JKU ... tracs straighter, wanders less, is smoother, plusher ... just better ... period ... until I go to work ... and hit that one magic bump or series bumps blah, blah, blah).
but each time I make headway I'll put it here, until it's cured. I did come across one other guy who wrote about similar issues, his fix was adjustable Rancho's (it's not the shock that mattered but the ability to tune it on the go that matters) once he had the damping tuned to the spring rate the DW was gone. He noted the same progression of the wobble I did as well.
Sorry for this retardedly long winded one, but it's really and experience in skidmarks I suffer from here.